This document provides an introduction to GIS and QGIS. It discusses:
- Who the instructor is and their background in GIS.
- An overview of what GIS is, including its ability to store, manipulate and display geographic data, and how it can be used to analyze spatial relationships and patterns.
- A brief demonstration of QGIS and its capabilities. QGIS is an open source GIS software that can perform many of the same functions as ArcGIS desktop.
Dave Murray presented on QGIS, an open source desktop GIS. He discussed why users should consider QGIS, its benefits, and limitations compared to commercial GIS software. Training materials and resources for learning QGIS were provided, including online courses, tutorials, and documentation. While QGIS is limited in some areas like advanced editing and cartography, it was positioned as a valuable free tool worth learning to expand one's GIS skills and have an alternative to expensive commercial software.
This is most benificial for the First year Engineering students.This presentation consists of videos and many applications of GIS. The processes and the other parts of GIS is also nicely explained.
GIS involves capturing, storing, managing, and analyzing spatial and attribute data related to locations on Earth. It allows users to visualize patterns and relationships in the data. A GIS links locational/spatial data to descriptive attribute data, enabling analysis of how features are related across space. It consists of hardware, software, data, people, methods, and various subsystems for inputting, storing, manipulating, and displaying geographic data and information. Common data formats in GIS include raster (grid cells) and vector (points, lines, polygons) representations. Maps are a key form of visualization and interface within GIS.
The document provides an introduction to Geographic Information Systems (GIS) and the open-source GIS software QGIS. It discusses John Snow's 1854 map of a cholera outbreak in London and how it helped establish epidemiology. It then defines GIS and describes common components like data input/output, data models, and editing tools. The document also demonstrates how to perform tasks in QGIS like adding vector and raster layers, importing GPX files, editing shapefiles, creating new layers, merging shapefiles, and filtering/separating data.
This document provides an outline for a presentation on geospatial technologies including remote sensing, GPS, mapping, surveying, and GIS. It begins with an introduction to the geomatic umbrella and defines key geospatial concepts. It then discusses remote sensing platforms and sensors, and provides examples of agricultural and forestry applications. It also summarizes GPS systems and applications. The document defines mapping and surveying and provides examples. It concludes with an overview of GIS hardware, software, data, and functions and discusses example applications in emergency management, petroleum management, and utilities.
Developing Efficient Web-based GIS ApplicationsSwetha A
The document discusses technologies for developing efficient web-based GIS applications. It describes mapping technologies like static map renderers, slippy maps, and Flash mapping. It also covers database technologies like Oracle, SQL Server, and normalization. Development standards discussed include web wireframing, languages like ASP and PHP, protocols like SOAP, and a three-tier architecture. The conclusion recommends Flash mapping or slippy maps, Oracle database, wireframing, SOAP protocol, and a three-tier architecture for developing efficient web-based GIS applications.
The document presents a presentation on Geographic Information Systems (GIS). It includes sections on what GIS is, its capabilities and components. GIS is a computer system for capturing, storing, analyzing and managing geographic information and spatial data. The key components of a GIS include hardware, software, data and people. GIS has many applications and uses spatial data and analysis to solve problems across many different domains.
What is Geography Information Systems (GIS)John Lanser
GIS is a computer-based information system used to capture, manage, update, analyze, display, and output spatial data and information to be used in a decision making context. It integrates hardware, software, data, people, and allows for the visualization and analysis of data with a geographic component. Some key applications of GIS include emergency response, transportation planning, site selection, and natural resource management.
Dave Murray presented on QGIS, an open source desktop GIS. He discussed why users should consider QGIS, its benefits, and limitations compared to commercial GIS software. Training materials and resources for learning QGIS were provided, including online courses, tutorials, and documentation. While QGIS is limited in some areas like advanced editing and cartography, it was positioned as a valuable free tool worth learning to expand one's GIS skills and have an alternative to expensive commercial software.
This is most benificial for the First year Engineering students.This presentation consists of videos and many applications of GIS. The processes and the other parts of GIS is also nicely explained.
GIS involves capturing, storing, managing, and analyzing spatial and attribute data related to locations on Earth. It allows users to visualize patterns and relationships in the data. A GIS links locational/spatial data to descriptive attribute data, enabling analysis of how features are related across space. It consists of hardware, software, data, people, methods, and various subsystems for inputting, storing, manipulating, and displaying geographic data and information. Common data formats in GIS include raster (grid cells) and vector (points, lines, polygons) representations. Maps are a key form of visualization and interface within GIS.
The document provides an introduction to Geographic Information Systems (GIS) and the open-source GIS software QGIS. It discusses John Snow's 1854 map of a cholera outbreak in London and how it helped establish epidemiology. It then defines GIS and describes common components like data input/output, data models, and editing tools. The document also demonstrates how to perform tasks in QGIS like adding vector and raster layers, importing GPX files, editing shapefiles, creating new layers, merging shapefiles, and filtering/separating data.
This document provides an outline for a presentation on geospatial technologies including remote sensing, GPS, mapping, surveying, and GIS. It begins with an introduction to the geomatic umbrella and defines key geospatial concepts. It then discusses remote sensing platforms and sensors, and provides examples of agricultural and forestry applications. It also summarizes GPS systems and applications. The document defines mapping and surveying and provides examples. It concludes with an overview of GIS hardware, software, data, and functions and discusses example applications in emergency management, petroleum management, and utilities.
Developing Efficient Web-based GIS ApplicationsSwetha A
The document discusses technologies for developing efficient web-based GIS applications. It describes mapping technologies like static map renderers, slippy maps, and Flash mapping. It also covers database technologies like Oracle, SQL Server, and normalization. Development standards discussed include web wireframing, languages like ASP and PHP, protocols like SOAP, and a three-tier architecture. The conclusion recommends Flash mapping or slippy maps, Oracle database, wireframing, SOAP protocol, and a three-tier architecture for developing efficient web-based GIS applications.
The document presents a presentation on Geographic Information Systems (GIS). It includes sections on what GIS is, its capabilities and components. GIS is a computer system for capturing, storing, analyzing and managing geographic information and spatial data. The key components of a GIS include hardware, software, data and people. GIS has many applications and uses spatial data and analysis to solve problems across many different domains.
What is Geography Information Systems (GIS)John Lanser
GIS is a computer-based information system used to capture, manage, update, analyze, display, and output spatial data and information to be used in a decision making context. It integrates hardware, software, data, people, and allows for the visualization and analysis of data with a geographic component. Some key applications of GIS include emergency response, transportation planning, site selection, and natural resource management.
This document provides an overview of using QGIS open source GIS software to load, manipulate, and classify geospatial data. It discusses loading data formats like shapefiles and geodatabases, exploring the QGIS interface, performing digitization and attribute editing, running topology rules to check for errors, and labeling layers to provide more information about mapped features. Exercises are demonstrated step-by-step to help users understand how to apply GIS theory and create basic maps in QGIS.
GIS is a system for managing and analyzing geographic data. It uses two main data models: vector, representing points, lines and polygons; and raster, representing data as a grid of cells. Common file formats include shapefiles for vector data and GeoTIFF and MrSID for raster. GIS data is referenced using coordinate systems like WGS84 for global latitude/longitude or HK80Grid for Hong Kong. ESRI's ArcGIS software allows viewing, editing, and publishing this geospatial data for mapping and analysis.
This document provides an introduction to geographic information systems (GIS). It defines GIS as a computer system for capturing, storing, analyzing and displaying spatially-referenced data. A GIS integrates database operations with maps in digital form and allows users to create interactive queries, analyze spatial information, edit maps and present results. The document outlines key components of a GIS including data, databases, processing capabilities, hardware and communications. It also discusses the importance of location in problem-solving and decision making as well as the history and business applications of GIS technology.
Raster data is commonly obtained by scanning maps or collecting aerial photographs and satellite images. Scanned map datasets don't normally contain spatial reference information (either embedded in the file or as a separate file). With aerial photography and satellite imagery, sometimes the location information delivered with them is inadequate, and the data does not align properly with other data one has. Thus, to use some raster datasets in conjunction with other spatial data, we need to align or georeference them to a map coordinate system. A map coordinate system is defined using a map projection (a method by which the curved surface of the earth is portrayed on a flat surface). Georeferencing a raster data defines its location using map coordinates and assigns the coordinate system of the data frame. Georeferencing raster data allows it to be viewed, queried, and analyzed with other geographic data.
Generally, we georeference raster data using existing spatial data (target data)—such as georeferenced rasters or a vector feature class—that resides in the desired map coordinate system. The process involves identifying a series of ground control points—known x,y coordinates—that link locations on the raster dataset with locations in the spatially referenced data (target data). Control points are locations that can be accurately identified on the raster dataset and in real-world coordinates. Many different types of features can be used as identifiable locations, such as road or stream intersections, the mouth of a stream, rock outcrops, the end of a jetty of land, the corner of an established field, street corners, or the intersection of two hedgerows. The control points are used to build a polynomial transformation that will shift the raster dataset from its existing location to the spatially correct location. The connection between one control point on the raster dataset (the from point) and the corresponding control point on the aligned target data (the to point) is a link.
Finally, the georeferenced raster file can be exported for further usage.
THIS PRESENTATION IS TO HELP YOU PERFORM THE TASK STEP BY STEP.
This document provides an overview of geographic information systems (GIS). It discusses that GIS combines maps with layered information about geographic features. The key components of GIS are computer systems, GIS software, procedures, data, and end users. GIS has various applications in technical areas like water resource management, environment, agriculture, as well as commercial, social, and administrative uses. GIS offers benefits over traditional paper maps and other software by allowing more efficient analysis of spatial and attribute data to support improved decision making.
A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data. The acronym GIS is sometimes used for geographical information science or geospatial information studies to refer to the academic discipline or career of working with geographic information systems and is a large domain within the broader academic discipline of Geoinformatics. In the simplest terms, GIS is the merging of cartography, statistical analysis, and computer science technology.
Talk about what relation between web and mapping. Also the process to create and collaborate on-line map using free source like mapserver, geoserver, postgis, openlayer.
This document provides information about the Global Positioning System (GPS). It discusses the history and development of GPS, including its three segments - space, control, and user. The space segment consists of GPS satellites that transmit signals. The control segment operates the satellites from ground stations. The user segment includes GPS receivers that can determine location from the satellite signals. The document outlines how GPS works by using triangulation of signals from multiple satellites. It also discusses sources of GPS errors, applications such as navigation and tracking, and advantages like accuracy and flexibility and disadvantages like indoor limitations.
The basic intention of this presentation is to help the beginners in GIS to understand what GIS is? It is a simple presentation about GIS, i mean an introductory one. Hope anyone finds it useful.
This document provides an overview of geographic information systems (GIS) and introduces key concepts related to GIS. It outlines the objectives of GIS as handling geographical data through spatial analysis and modeling. The document then covers various GIS topics like representing real world data, software, data modeling, databases, and applications. It emphasizes that GIS is a system for capturing, storing, analyzing and managing spatial or geographic data and associated attributes.
This document discusses spatial analysis and modeling in a geographical information system. It defines spatial analysis as gaining an understanding of patterns and processes underlying geographic features in order to make better decisions and understand phenomena. The document outlines four types of spatial analysis: spatial data manipulation, spatial data analysis, spatial statistical analysis, and spatial modeling. It also describes different vector and raster spatial analysis techniques, such as clipping, overlaying, buffering, and slope/aspect calculations. Spatial modeling is defined as using models to predict spatial outcomes and enable "what if" analyses.
This document discusses the benefits of implementing a web-based GIS pilot project for Exploration. It would provide a centralized location for all relevant exploration data, with customized access for different user groups. A web-based system could more easily share and expose information across the organization. The goals are to make maps and data more intuitive, up-to-date, and tailored for decision-making. Key challenges include integrating complex workflows and data from different sources and applications. The document recommends management commitment, an Exploration GIS vision and strategy, and establishing a data model to ensure successful implementation.
DEFINITION :
GIS is a powerful set of tools for collecting, storing , retrieving at will, transforming and displaying spatial data from the real world for a particular set of purposes
APPLICATION AREAS OF GIS
Agriculture
Business
Electric/Gas utilities
Environment
Forestry
Geology
Hydrology
Land-use planning
Local government
Mapping
11. Military
12. Risk management
13. Site planning
14. Transportation
15. Water / Waste water industry
COMPONENTS OF GIS
DATA INPUT
SPATIAL DATA MODEL
Data Model:
It describes in an abstract way how the data is represented in an information system or in DBMS
Spatial Data Model :
The models or abstractions of reality that are intended to have some similarity with selected aspects of the real world
Creation of analogue and digital spatial data sets involves seven levels of model development and abstraction
SPATIAL DATA MODEL
Conceptual model : A view of reality
Analog model : Human conceptualization leads to analogue abstraction
Spatial data models : Formalization of analogue abstractions without any conventions
Database model : How the data are recorded in the computer
Physical computational model : Particular representation of the data structures in computer memory
Data manipulation model : Accepted axioms and rules for handling the data
SPATIAL DATA MODEL
SPATIAL DATA MODEL
Objects on the earth surface are shown as continuous and discrete objects in spatial data models
Types of data models
Raster data model
vector data models
RASTER DATA MODEL
Basic Elements :
Extent
Rows
Columns
Origin
Orientation
Resolution: pixel = grain = grid cell
Ex: Bit Map Image (BMP),Joint Photographic Expert Group (JPEG), Portable Network Graphics(PNG) etc
RASTER DATA MODEL
VECTOR DATA MODEL
Basic Elements:
Location (x,y) or (x,y,z)
Explicit, i.e. pegged to a coordinate system
Different coordinate system (and precision) require different values
o e.g. UTM as integer (but large)
o Lat, long as two floating point numbers +/-
Points are used to build more complex features
Ex: Auto CAD Drawing File(DWG), Data Interchange(exchange) File(DXF), Vector Product Format (VPF) etc
VECTOR DATA MODEL
RASTER vs VECTORRaster is faster but Vector is corrector
TESSELLATIONS OF CONTINUOUS FIELDS
Triangular Irregular Network: (TIN)
TIN is a vector data structure for representing geographical information that is continuous
Digital elevation model
TIN is generally used to create Digital Elevation Model (DEM)
DIGITAL ELEVATION MODEL
DATA STRUCTURES
Data structure tells about how the data is stored
Data organization in raster data structures
Each cell is referenced directly
Each overlay Is referenced directly
Each mapping unit is referenced directly
Each overlay is separate file with general header
TYBSC IT PGIS Unit I Chapter I- Introduction to Geographic Information SystemsArti Parab Academics
A Gentle Introduction to GIS The nature of GIS: Some fundamental observations, Defining GIS, GISystems, GIScience and GIApplications, Spatial data and Geoinformation. The real world and representations of it: Models and modelling, Maps, Databases, Spatial databases and spatial analysis
This document discusses Web GIS and Web mapping. It defines Web GIS as a type of distributed information system comprising a GIS server and a client, typically accessed through a web browser. The main components of Web GIS are identified as the client (web browser), internet connection, web server, map server, and metadata. Various functions and advantages of Web GIS are outlined, including visualization, querying geospatial data, collecting/editing information, disseminating information, and analysis. Different types of web maps are also described such as analytical, animated, real-time, collaborative, and static web maps. In conclusion, the document emphasizes that successful Web GIS development requires considering the implementation as a process rather than a single
The document provides an introduction to ArcGIS. It outlines that it will discuss what GIS is, how geographic data is represented in GIS, how data is stored in ArcGIS, GIS maps, GIS analysis processes, what ArcGIS is, and planning a GIS project. It then proceeds to define GIS, explain how geographic data is modeled in vector and raster formats, describe how data is organized and stored in an ArcGIS geodatabase, discuss GIS mapping and visualization, and overview spatial analysis tools in ArcGIS.
This document provides a history of GIS from 1975 to 2011, focusing on key developments, technologies, contributors and events. It covers the commercialization of GIS starting in the late 1970s, the development of early GIS software and technologies by Esri and others, as well as significant advances in related fields like computer processing and the internet that influenced GIS. The document is intended as an informal timeline and overview, rather than an authoritative historical account.
Geographic Information Systems (GIS) is a system that uses computer hardware, software, and personnel to analyze and present spatial information tied to locations. Key components of a GIS include geographic data about locations, information on attributes of those locations, software to store and process the data, hardware, and users. GIS brings together cartography, remote sensing, geography, and database technology to capture, store, analyze and display spatially-referenced data for the purposes of understanding relationships and patterns in that data. Common uses of GIS include applications in emergency services, environmental monitoring, business, government, education, and any field where the analysis of spatial data is important.
The document discusses what geospatial data is, noting that practically all data has some spatial attribute or context since everything happens somewhere. It explains that geospatial data can come from existing datasets or be created by geocoding or geo-tagging data to assign it spatial coordinates or locations. The document also outlines different ways geospatial data can be mapped, analyzed, shared, and referenced for use in geographic information systems.
This document provides an overview of using QGIS open source GIS software to load, manipulate, and classify geospatial data. It discusses loading data formats like shapefiles and geodatabases, exploring the QGIS interface, performing digitization and attribute editing, running topology rules to check for errors, and labeling layers to provide more information about mapped features. Exercises are demonstrated step-by-step to help users understand how to apply GIS theory and create basic maps in QGIS.
GIS is a system for managing and analyzing geographic data. It uses two main data models: vector, representing points, lines and polygons; and raster, representing data as a grid of cells. Common file formats include shapefiles for vector data and GeoTIFF and MrSID for raster. GIS data is referenced using coordinate systems like WGS84 for global latitude/longitude or HK80Grid for Hong Kong. ESRI's ArcGIS software allows viewing, editing, and publishing this geospatial data for mapping and analysis.
This document provides an introduction to geographic information systems (GIS). It defines GIS as a computer system for capturing, storing, analyzing and displaying spatially-referenced data. A GIS integrates database operations with maps in digital form and allows users to create interactive queries, analyze spatial information, edit maps and present results. The document outlines key components of a GIS including data, databases, processing capabilities, hardware and communications. It also discusses the importance of location in problem-solving and decision making as well as the history and business applications of GIS technology.
Raster data is commonly obtained by scanning maps or collecting aerial photographs and satellite images. Scanned map datasets don't normally contain spatial reference information (either embedded in the file or as a separate file). With aerial photography and satellite imagery, sometimes the location information delivered with them is inadequate, and the data does not align properly with other data one has. Thus, to use some raster datasets in conjunction with other spatial data, we need to align or georeference them to a map coordinate system. A map coordinate system is defined using a map projection (a method by which the curved surface of the earth is portrayed on a flat surface). Georeferencing a raster data defines its location using map coordinates and assigns the coordinate system of the data frame. Georeferencing raster data allows it to be viewed, queried, and analyzed with other geographic data.
Generally, we georeference raster data using existing spatial data (target data)—such as georeferenced rasters or a vector feature class—that resides in the desired map coordinate system. The process involves identifying a series of ground control points—known x,y coordinates—that link locations on the raster dataset with locations in the spatially referenced data (target data). Control points are locations that can be accurately identified on the raster dataset and in real-world coordinates. Many different types of features can be used as identifiable locations, such as road or stream intersections, the mouth of a stream, rock outcrops, the end of a jetty of land, the corner of an established field, street corners, or the intersection of two hedgerows. The control points are used to build a polynomial transformation that will shift the raster dataset from its existing location to the spatially correct location. The connection between one control point on the raster dataset (the from point) and the corresponding control point on the aligned target data (the to point) is a link.
Finally, the georeferenced raster file can be exported for further usage.
THIS PRESENTATION IS TO HELP YOU PERFORM THE TASK STEP BY STEP.
This document provides an overview of geographic information systems (GIS). It discusses that GIS combines maps with layered information about geographic features. The key components of GIS are computer systems, GIS software, procedures, data, and end users. GIS has various applications in technical areas like water resource management, environment, agriculture, as well as commercial, social, and administrative uses. GIS offers benefits over traditional paper maps and other software by allowing more efficient analysis of spatial and attribute data to support improved decision making.
A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data. The acronym GIS is sometimes used for geographical information science or geospatial information studies to refer to the academic discipline or career of working with geographic information systems and is a large domain within the broader academic discipline of Geoinformatics. In the simplest terms, GIS is the merging of cartography, statistical analysis, and computer science technology.
Talk about what relation between web and mapping. Also the process to create and collaborate on-line map using free source like mapserver, geoserver, postgis, openlayer.
This document provides information about the Global Positioning System (GPS). It discusses the history and development of GPS, including its three segments - space, control, and user. The space segment consists of GPS satellites that transmit signals. The control segment operates the satellites from ground stations. The user segment includes GPS receivers that can determine location from the satellite signals. The document outlines how GPS works by using triangulation of signals from multiple satellites. It also discusses sources of GPS errors, applications such as navigation and tracking, and advantages like accuracy and flexibility and disadvantages like indoor limitations.
The basic intention of this presentation is to help the beginners in GIS to understand what GIS is? It is a simple presentation about GIS, i mean an introductory one. Hope anyone finds it useful.
This document provides an overview of geographic information systems (GIS) and introduces key concepts related to GIS. It outlines the objectives of GIS as handling geographical data through spatial analysis and modeling. The document then covers various GIS topics like representing real world data, software, data modeling, databases, and applications. It emphasizes that GIS is a system for capturing, storing, analyzing and managing spatial or geographic data and associated attributes.
This document discusses spatial analysis and modeling in a geographical information system. It defines spatial analysis as gaining an understanding of patterns and processes underlying geographic features in order to make better decisions and understand phenomena. The document outlines four types of spatial analysis: spatial data manipulation, spatial data analysis, spatial statistical analysis, and spatial modeling. It also describes different vector and raster spatial analysis techniques, such as clipping, overlaying, buffering, and slope/aspect calculations. Spatial modeling is defined as using models to predict spatial outcomes and enable "what if" analyses.
This document discusses the benefits of implementing a web-based GIS pilot project for Exploration. It would provide a centralized location for all relevant exploration data, with customized access for different user groups. A web-based system could more easily share and expose information across the organization. The goals are to make maps and data more intuitive, up-to-date, and tailored for decision-making. Key challenges include integrating complex workflows and data from different sources and applications. The document recommends management commitment, an Exploration GIS vision and strategy, and establishing a data model to ensure successful implementation.
DEFINITION :
GIS is a powerful set of tools for collecting, storing , retrieving at will, transforming and displaying spatial data from the real world for a particular set of purposes
APPLICATION AREAS OF GIS
Agriculture
Business
Electric/Gas utilities
Environment
Forestry
Geology
Hydrology
Land-use planning
Local government
Mapping
11. Military
12. Risk management
13. Site planning
14. Transportation
15. Water / Waste water industry
COMPONENTS OF GIS
DATA INPUT
SPATIAL DATA MODEL
Data Model:
It describes in an abstract way how the data is represented in an information system or in DBMS
Spatial Data Model :
The models or abstractions of reality that are intended to have some similarity with selected aspects of the real world
Creation of analogue and digital spatial data sets involves seven levels of model development and abstraction
SPATIAL DATA MODEL
Conceptual model : A view of reality
Analog model : Human conceptualization leads to analogue abstraction
Spatial data models : Formalization of analogue abstractions without any conventions
Database model : How the data are recorded in the computer
Physical computational model : Particular representation of the data structures in computer memory
Data manipulation model : Accepted axioms and rules for handling the data
SPATIAL DATA MODEL
SPATIAL DATA MODEL
Objects on the earth surface are shown as continuous and discrete objects in spatial data models
Types of data models
Raster data model
vector data models
RASTER DATA MODEL
Basic Elements :
Extent
Rows
Columns
Origin
Orientation
Resolution: pixel = grain = grid cell
Ex: Bit Map Image (BMP),Joint Photographic Expert Group (JPEG), Portable Network Graphics(PNG) etc
RASTER DATA MODEL
VECTOR DATA MODEL
Basic Elements:
Location (x,y) or (x,y,z)
Explicit, i.e. pegged to a coordinate system
Different coordinate system (and precision) require different values
o e.g. UTM as integer (but large)
o Lat, long as two floating point numbers +/-
Points are used to build more complex features
Ex: Auto CAD Drawing File(DWG), Data Interchange(exchange) File(DXF), Vector Product Format (VPF) etc
VECTOR DATA MODEL
RASTER vs VECTORRaster is faster but Vector is corrector
TESSELLATIONS OF CONTINUOUS FIELDS
Triangular Irregular Network: (TIN)
TIN is a vector data structure for representing geographical information that is continuous
Digital elevation model
TIN is generally used to create Digital Elevation Model (DEM)
DIGITAL ELEVATION MODEL
DATA STRUCTURES
Data structure tells about how the data is stored
Data organization in raster data structures
Each cell is referenced directly
Each overlay Is referenced directly
Each mapping unit is referenced directly
Each overlay is separate file with general header
TYBSC IT PGIS Unit I Chapter I- Introduction to Geographic Information SystemsArti Parab Academics
A Gentle Introduction to GIS The nature of GIS: Some fundamental observations, Defining GIS, GISystems, GIScience and GIApplications, Spatial data and Geoinformation. The real world and representations of it: Models and modelling, Maps, Databases, Spatial databases and spatial analysis
This document discusses Web GIS and Web mapping. It defines Web GIS as a type of distributed information system comprising a GIS server and a client, typically accessed through a web browser. The main components of Web GIS are identified as the client (web browser), internet connection, web server, map server, and metadata. Various functions and advantages of Web GIS are outlined, including visualization, querying geospatial data, collecting/editing information, disseminating information, and analysis. Different types of web maps are also described such as analytical, animated, real-time, collaborative, and static web maps. In conclusion, the document emphasizes that successful Web GIS development requires considering the implementation as a process rather than a single
The document provides an introduction to ArcGIS. It outlines that it will discuss what GIS is, how geographic data is represented in GIS, how data is stored in ArcGIS, GIS maps, GIS analysis processes, what ArcGIS is, and planning a GIS project. It then proceeds to define GIS, explain how geographic data is modeled in vector and raster formats, describe how data is organized and stored in an ArcGIS geodatabase, discuss GIS mapping and visualization, and overview spatial analysis tools in ArcGIS.
This document provides a history of GIS from 1975 to 2011, focusing on key developments, technologies, contributors and events. It covers the commercialization of GIS starting in the late 1970s, the development of early GIS software and technologies by Esri and others, as well as significant advances in related fields like computer processing and the internet that influenced GIS. The document is intended as an informal timeline and overview, rather than an authoritative historical account.
Geographic Information Systems (GIS) is a system that uses computer hardware, software, and personnel to analyze and present spatial information tied to locations. Key components of a GIS include geographic data about locations, information on attributes of those locations, software to store and process the data, hardware, and users. GIS brings together cartography, remote sensing, geography, and database technology to capture, store, analyze and display spatially-referenced data for the purposes of understanding relationships and patterns in that data. Common uses of GIS include applications in emergency services, environmental monitoring, business, government, education, and any field where the analysis of spatial data is important.
The document discusses what geospatial data is, noting that practically all data has some spatial attribute or context since everything happens somewhere. It explains that geospatial data can come from existing datasets or be created by geocoding or geo-tagging data to assign it spatial coordinates or locations. The document also outlines different ways geospatial data can be mapped, analyzed, shared, and referenced for use in geographic information systems.
The document outlines three options for a GEO 565 course: 1) an annotated bibliography uploaded online, 2) a term paper, or 3) an original mapping mashup and report uploaded online. It provides requirements and deadlines for each option. It also contains additional information about concepts in GIS like data models, data types, analysis tools, and conferences. Students must choose an option by January 18th, with options 1 and 2 due by March 11th and option 3 due by March 16th.
The document provides definitions and examples of what a Geographic Information System (GIS) is. It discusses how GIS involves tools to collect, manage, use, share and interpret spatial data to understand relationships and patterns. A GIS allows users to visualize, analyze and draw conclusions from geographical data. While GIS often involves computer software and hardware, it does not necessarily require technology, as paper maps and mental maps can also serve as GIS.
This document provides an introduction to geographic information systems (GIS) and remote sensing. It defines different types of data used in GIS, including spatial data tied to locations and aspatial data not tied to locations. It describes the three main components of GIS as data management, analysis, and visualization. GIS uses layers to store and manipulate different types of geographic data and relationships. Remote sensing involves collecting geographic data from aircraft or satellites using different parts of the electromagnetic spectrum.
Leslie Pelch, Outreach Director for Vermont Center for Geographic Information, outlines the benefits and tools for data visualization at 7th Annual Media Maven Luncheon hosted by CCTV and Common Good VT.
This document discusses geovisualization and maps. It begins by defining key concepts like cartography, geographic data, and how maps represent reality through models. Maps are described as useful because they make invisible patterns and relationships visible. The document then discusses different types of maps, like paper maps, on-screen maps, and web maps, and how they disseminate geographic data. It explores trends in maps, like neogeography and user-generated content. Finally, it discusses using maps to both present and explore data, as well as areas of future research like user studies.
The document discusses Quantum GIS, an open source geographic information system (GIS) software. It provides an overview of GIS concepts like vector and raster data representation and different data formats. The presentation then demonstrates how to use Quantum GIS to view, analyze, convert and manipulate geospatial data. It recommends Quantum GIS for tasks involving geodata and provides information on learning more about open source GIS tools and data.
The document discusses Quantum GIS, an open source geographic information system (GIS) software. It provides an overview of GIS concepts like vector and raster data representation and different data formats. The presentation then demonstrates how to use Quantum GIS to view, analyze, convert and manipulate geospatial data. It recommends Quantum GIS for tasks involving geodata and provides information on learning more about open source GIS tools and data.
This document provides an overview of geographic information systems (GIS). It discusses key concepts in GIS including representing geographic features using vector and raster data models, different data types like points, lines and polygons, scale and resolution, coordinate systems and map projections. The document also touches on accuracy, editing errors in GIS data, and using GIS to answer questions about location, conditions, trends, patterns and modeling.
My special talk on 'GIS & Remote Sensing-Introduction to the Primer’ is a part of the 'Learn from the Leaders- 2' webinar series organized by IEEE SIGHT, Bombay section on May 25th, 2021
Geographic Information Systems (GIS) is a system of computer software, hardware, and data that helps users manipulate, analyze, and present spatial information. GIS turns data into information by allowing users to visualize, analyze, and interact with spatial data linked to locations. Common uses of GIS include emergency services, environmental monitoring, business site selection, transportation planning, and more. GIS combines data from various sources and allows users to ask questions of and get insights from the interactive maps and databases.
This document provides a whirlwind tour of GIS concepts in 25 slides. It defines GIS as geographical information science and discusses data capture methods like surveys and remote sensing. It explores analysis and visualization techniques, different GIS platforms, common spatial phenomena modeled in GIS, and modeling approaches. The document also covers GIS history, software, data types, attributes, overlay operations, coordinate reference systems, common file formats, data storage, open source GIS, web GIS, and potential future directions for GIS including location-based services and cloud computing.
This document provides a whirlwind tour of GIS concepts in 25 slides. It defines GIS as geographical information science and discusses data capture techniques including remote sensing and sensor networks. It explores analysis and visualization of spatial data in 2D and 3D maps and how visualization can enable further analysis. The document also briefly outlines the history of GIS software and formats, as well as concepts like spatial data types, attributes, modeling frameworks, coordinate reference systems, and industry standard and open source GIS tools. It concludes with discussions of future directions for GIS including location-based services, sensors, cloud computing, and social implications.
This document provides a whirlwind tour of GIS concepts in 25 slides. It defines GIS as geographical information science and discusses data capture methods like remote sensing and GPS. It explains how spatial data can be analyzed and visualized in 2D and 3D maps. Common data types in GIS like vector and raster data are introduced along with concepts like attributes, overlay operations, and coordinate reference systems. Popular GIS software like ArcGIS and open source options are overviewed. The document concludes by discussing emerging areas in GIS like web mapping, mobile apps, sensor networks, and cloud computing.
This document provides a whirlwind tour of GIS concepts in 25 slides. It defines GIS as geographical information science and discusses data capture methods like surveys and remote sensing. It explains how GIS allows for analysis and visualization of spatial data in 2D and 3D maps. Key aspects of GIS covered include its history, common data types of vector and raster, attributes, modeling frameworks, data storage, open source options, and future directions such as location-based services and cloud computing. The document aims to quickly introduce fundamental GIS concepts.
The document discusses Esri's tools and roadmap for working with multi-dimensional (MD) scientific data in ArcGIS. It outlines Esri's efforts to directly read HDF, GRIB, and netCDF files as raster layers or feature/table views in ArcGIS. MD mosaic datasets allow users to manage variables and dimensions across multiple files and perform on-the-fly computations and visualization of MD data. New functions have been added to improve MD data analysis and visualization, including a vector field renderer to depict raster data as vectors. Esri is also working to better support OPeNDAP data sources.
GIS and Remote Sensing Training at Pitney Bowes SoftwareNishant Sinha
This presentation was made for internal training in Pitney Bowes. The content has many references across and has not been compiled. A simple ppt will help a lot.
Fundamentals of Geographical Information System.pptbimalp7
This document provides information about a GIS fundamentals course taught by Dr. Ronald Briggs at the University of Texas at Dallas, including details about the instructor, texts, evaluation, and an overview of key GIS concepts. It describes GIS as a system of integrated computer tools for processing geographic data using location on Earth's surface. It also outlines the GIS data model involving layers of spatial and attribute information and representations through raster and vector formats.
Come with an idea - go home with a web map: Tools for sharing maps and vector...Stefan Keller
When speaking of web maps, Google set the pace and was the one who made these geospatial technologies mainstream. This workshop presents free alternatives. Often they are perhaps less streamlined but more professional and specific to a certain use case. The use case that will be treated here is statistical data which serves as input for a ‚story map‘. This story map tells a story, meaning an idea (provided by the participants) to be visualized by a thematic web map (syn. geovisualization, infographic).
Erich Purpur is a science and engineering librarian who supports the UVA community in all aspects of the research process through research data services. He uses Geographic Information Systems (GIS) and the programming language Python to help analyze, visualize, and manipulate spatial data for research projects. As examples, he used GIS and Python to calculate the total distance an eagle flew from GPS data points and to visualize monthly patient data from a UVA oncology department on interactive maps. Purpur finds that these tools allow researchers to see and interact with their data in useful ways and help automate repetitive tasks, fitting with his goal of supporting all phases of the research process.
- The document summarizes a class on applying GIS methods in public policy decisions that was taught using the open-source software QGIS instead of ESRI's ArcGIS.
- The instructor has a GIS background and helps people with all aspects of the research process. The class was offered through the Frank Batten School of Leadership and Public Policy at the University of Virginia.
- Using QGIS allowed the class to be taught for free on the university's Mac computers since the IT department no longer widely supports desktop software. However, installing QGIS on 17 student systems led to various technical issues to solve.
Erich Purpur is a science and engineering librarian who supports researchers at UVA. He discusses how Geographic Information Systems (GIS) and the programming language Python can be used to analyze, visualize, and manipulate spatial data. As an example, he describes how an undergraduate used GIS and Python to convert latitude and longitude coordinates for over 6,000 data points collected from an eagle's flight into distances and calculate that the eagle flew around 79 miles in 3 hours. Purpur notes that researchers across disciplines at UVA utilize these tools to see and work with their data.
This document provides an overview of how to conduct a literature review using the tool Publish or Perish. It defines a literature review as a survey of published research in an area that combines summary and synthesis. Conducting a literature review establishes existing knowledge, identifies gaps, and situates an argument in context. Publish or Perish allows users to find seminal articles, trace the development of a field, and identify important journals. When reading sources, researchers should evaluate the authority and relevance of information. Organization is key, and citation management tools like Zotero, Mendeley, and EndNote can help track the large number of sources involved in a literature review.
iCERi 2016 - 9th Annual International Conference of Education, Research, and ...epurpur
The DeLaMare Science & Engineering Library at the University of Nevada, Reno underwent a transformation from 2012 onward to become a vibrant makerspace. The library now offers resources like 3D printing, laser cutting, and a technology lending program to support over 6,000 students in hands-on, active learning. A variety of courses across different subject areas utilize the makerspace for projects, from engineering students 3D printing design pieces to geosciences students creating maps to art students learning new techniques. Going forward, the library aims to further integrate the makerspace into academic programs and develop additional outreach.
iCERi 2016 - 9th Annual International Conference of Education, Research, and ...epurpur
This document discusses incorporating spatial analysis and GIS into social work curriculum. It describes a class project where students surveyed the homeless population in Reno, Nevada and mapped the data using GIS tools. Students gathered data on zones in the city and analyzed trends like veteran homelessness. The project showed social work students how GIS can be used as a data visualization and analysis tool to inform social work practice and showcase work to stakeholders.
International Association for Social Science Information Services & Technolog...epurpur
The document summarizes the GIS services provided by the libraries at the University of Nevada, Reno, which began in 2014 with technical support and data services for over 21,000 students across various departments, despite limited staff and resources. Key aspects included partnering with student tutoring services on a trial basis, assessing needs, and plans to expand support through additional student hours and potential new staff with assistance from university agencies.
American Association for the Advancement of Science Pacific Division (AAAS-PD...epurpur
Erich Purpur and Amber Sherman presentation at the American Association for the Advancement of Science - Pacific Division at San Francisco State University. June 6th, 2015. Digital Preservation of 3D Objects in Academic Libraries
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
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How to Fix the Import Error in the Odoo 17Celine George
An import error occurs when a program fails to import a module or library, disrupting its execution. In languages like Python, this issue arises when the specified module cannot be found or accessed, hindering the program's functionality. Resolving import errors is crucial for maintaining smooth software operation and uninterrupted development processes.
How to Build a Module in Odoo 17 Using the Scaffold MethodCeline George
Odoo provides an option for creating a module by using a single line command. By using this command the user can make a whole structure of a module. It is very easy for a beginner to make a module. There is no need to make each file manually. This slide will show how to create a module using the scaffold method.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
2. Who am I?
Erich Purpur
Research Librarian for Science & Engineering
Brown Science & Engineering Library
-Serve as Liaison to various engineering departments at UVA
-Help people with research
-information discovery
-python programming
-GIS projects
-Teaching
-For-credit classes and workshops
-both GIS and python
3. GIS Experience
-BS in Geography w/ GIS concentration
-Worked on wetlands ecology protection projects
-started offering GIS services (similar to Scholar’s Lab) at previous job
-Now:
-teach GIS related classes and workshops
-sometimes help people with research projects
-GIS consulting on the side
-All QGIS all the time
-and other open source tools (python, PostgreSQL)
4. What will you learn today?
-Familiarity with GIS concepts
-Talk about project workflow
-Self Help
6. What is QGIS?
-Free and Open Source GIS Software
-An OSGeo project
-packaged with a bunch of other open source libraries and tools
-An alternative to ESRI/ArcGIS
7. Why use QGIS?
-Because it is free
-Linux and Mac compatible
-Because you are a fan of open source / are a developer
-Maybe you are an ESRI hater?
8. What can you do with it?
-Pretty much everything you can do with ArcMap, ArcGIS Pro,
or ArcGIS online
-different functionality available as well, because people build
their own
-same file types as ArcGIS, import between them
10. What is GIS?
-A computer system capable of assembling, storing, manipulating, analyzing, and
displaying geographically referenced information.
What does this mean?
-GIS is a data visualization tool and is useful for looking at spatial relationships and
patterns between objects. You can discover and communicate meaningful patterns
in your data
-GIS is not scary and is not only for geographers. A GIS is a tool which applies to
nearly every field including the sciences, humanities, social sciences.
-The output is a map but the power lies in the data behind the image
-GIS skills are a literacy
12. What can you do with GIS?
-Show where things are
-Show change over time/track changing data
-See and communicate meaningful patterns in your data
13. Properties of Real World Geographic Information
-Location
-Attributes
-Spatial Relationships
14. Geographic Reality
-Geographic features are recreated on the computer using Data Models
Vector Data
-Point, Line, Area (polygon)
-Values can be assigned to each point, line, or area
Raster Data
-breaks the earth down into a grid
-each cell represents an area in real life
-Spatial resolution
-values are assigned to each grid cell, much like
values are assigned to each vector point
-common examples:
-Satellite images
16. Location of Objects
-the absolute location of objects is determined by coordinate systems
Geographic Coordinate System
-a network of intersecting lines
-latitude (North/South)
-longitude (East/West)
-starting point at the intersection of equator
and prime meridian
17. Map Projections
-Because the earth is round,
displaying it on a flat surface is
problematic
-The image will be somewhat
skewed
-Different projections focus on
different areas of the earth and
attempt to eliminate skew
-Getting data to display in the
same map projection is
sometimes easier said than done.
20. GIS Projects…
Gathering Data
-often times the hardest part!
-Data can be found…
-online data repositories (add more info and images)
-City of Charlottesville has a data portal
-remote sensing
-taken by satellites in space
-Digitizing/Scanning paper objects
-gather it yourself
-with a GPS unit
-sometimes it appears via some form of luck and magic
Data Storage
-occasionally massive amounts of data are used and storage can be an issue
21. Self Help!
-There are a lot of resources and a huge user community online
-Your question is not unique
-QGIS Documentation
- https://www.qgis.org/en/docs/index.html
-ArcGIS Documentation
- https://doc.arcgis.com/en/
-Stack Exchange – An entire GIS and QGIS arm
- https://gis.stackexchange.com/
-GeoNet – ESRI’s Online Community
- https://community.esri.com/
22. How to learn more QGIS
-Follow up with my workbook
-Learning QGIS 3rd Edition – Anita Graser
https://search.lib.virginia.edu/catalog/u7237739
-available through UVA library!
-Ask for more help
-me or Scholar’s lab
Editor's Notes
Hi Everyone, my name is Erich Purpur. I am a librarian in the DeLaMare Science & Engineering Library. The DeLaMare library exists on campus for everyone, but specifically we serve the needs of the science and engineering community on campus. I have a BS in Geography with a GIS concentration from Appalachian State University, and a MS in Library Science from the University of North Carolina, Chapel Hill. Though my background is in GIS (Geographic Information Systems) I have several job responsibilities, which are:
1- The DeLaMare Library hosts a makerspace, much of which is on the first floor. We provide access for all to expensive/rare tools and equipment like 3D printers, 3D scanners, laser cutter, vinyl cutter, lendable technology, collaborative learning space, and more. The care, feeding, maintenance, and upkeep of these resources is a shared responsibility among DeLaMare staff. Our technology is available for anyone, including people unaffiliated with UNR. Learn more about our resources here: (http://www.delamare.unr.edu)
2- I am a liaison to several departments on campus. Which means, if they need something from the library to support their curriculum and research, I am the official library person they are supposed to go through to acquire this. My current liaison responsibilities are Geography, Civil & Environmental Engineering, and Biomedical & Electrical Engineering
3- GIS! I coordinate GIS services at UNR libraries, which are primarily hosted in the DeLaMare Library. We offer walk-in tutoring availability Monday-Friday for anyone. Hours vary by semester, but tutoring generally happens in the afternoon. See tutoring availability here: (http://unr.libcal.com/booking/GIS). I am also happy to meet at other times if those don’t work for you. In addition, I teach this exact Introduction to GIS class the first Friday of each month at 2pm in room 121 in the Knowledge Center, also called the Dataworks Lab.
This is sort of a nuts and bolts introduction to GIS and its applications. Today I hope to familiarize you with GIS concepts such as data models and map projections. We are going to walk through a simple exercise using ArcGIS which I hope serves as an introduction to the software. Things I hope you gather from the exercise are:
-Most people only need a small subset of GIS functionality available in the ArcGIS software package.
-Depending on your needs, you may not need to learn ArcGIS. You could use ArcGIS Online, Google Earth, or another free mapping tool. Many tools exist and finding one to meet your needs is important
Map literacy skills are important and you already have them because you use them in your every day life. Take a look the 3 common examples of map usage.
The plain old definition of “What is a GIS?” never really resonated with me. Seeing the definition actually put into play was a lot more valuable I feel like. But we will get there later.
A GIS is basically a tool for data visualization, which can be applied to nearly everyone’s work and research including people in the sciences, humanities, and social sciences. Geographic Information Systems model real world objects by representing reality through data models. Attributes are linked to these objects to make them more meaningful. Finally, the spatial relationships between objects are examined to determine value and patterns in whatever it is you are studying. You do not need to use ArcMap to do this. Tools like Google Earth can be useful too. Depending on the project, you may be able to get away with using Google Earth to show relative locations of things. Simple data layers like roads and points of interest are built into Google Earth and you can add your own information to Google Earth maps too. Lastly, GIS skills are a literacy just like any other software program, learning to manage your money, playing an instrument, etc. They can be learned but there is a learning curve.
All the layers are stacked on top of each other to create a representation of the real world. Just like layers in a cake, only the top layer is visible.
The most common things people use GIS for are not overly complicated. Once again, GIS is a data visualization tool which you can use to see patterns and trends in spatial data. Figuring out the spatial relationships between objects has a lot of value in nearly every field in some way or another.
Common things people use GIS for:
-Show where things are
-Show change over time
-keep track of changing data
-communicate meaningful patterns in your data
Really, the last bullet point is the most important, and the point of all of this. The end results of most GIS projects is a map. Your map should be readable to key stakeholders, who often don’t know much about your project. If you communicate the meaningful patterns in your data, you can get the point across to others.
I like to use this map as an example of what data can be communicated visually. Take this map of Los Angeles county schools. The black shapes outline school districts. Each school district is shaded based on the average income of that area. On top of that, we have yellow and red dots. Red dots indicate areas where more than 30% of schoolteachers are uncredentialed. Yellow dots indicate areas with fewer than 10% uncredentialed teachers.
Now, lets think about what these colors and dots mean. The shading tells us not only about income, but other demographics of this area. In LA county, like most places, wealthy people live near each other and poor people live near each other. In this case, rich people live in the hills surrounding the city, while poor people live in the valley. This also probably tells you something about the spatial distribution of ethnicity as well.
Regarding the dots, red dots are “warning” signs and are clustered in areas of low income. Yellow dots are in areas of high income. Obviously, rich people have more money to pay for good teachers. However, sometimes when viewed spatially, you can see patterns in your data that were not previously obvious when viewed in a tabular or some other format. This can steer your decision making in the future.
As we saw in slide 7 (“What does it look like?”), every facet of the real world is represented as a layer, but not all layers are equal.
What is geographic reality? A computer creates a representation of the earth by using data models. A data model is a method used to represent real world objects on a computer. There are basically two data models used in a GIS, vector and raster.
Vector Data- Represents real world objects as points, lines, or polygons. This is used for representing clearly defined objects on the landscape like trees, houses, roads, etc. It is also useful for defining spatial relationships. You can see that a river flows into a lake or that trees are north of the river.
Raster Data- breaks the earth down into a grid where each cell represents an area in real life. The amount of area represented by each cell is known as the spatial resolution. Values are assigned to each grid cell, much like values can be assigned to a vector point. The value assigned to each grid cell is the average elevation, land cover, etc value across that grid cell.
Common uses: Satellite Images, DEMs
Raster data is used for representing continuously changing attributes over space
Here same image shown with different spatial resolutions. The optimal spatial resolution is determined by the size and scope of your project. High resolution is good but also leads to large files and slow processing time. If you are studying the entire United States, you probably don’t need 1meter spatial resolution but if you are focused on a town or neighborhood, small resolution will be more appropriate. Low resolution imagery isn’t necessarily bad. The optimal resolution just depends on the study area of your project.
The absolute location of objects on the earths surface are determined by coordinate systems.
Geographic Coordinate Systems are a reference system for the curved surface of the earth.
These lines of latitude and longitude determine the absolute location of objects on the globe. For example, Reno’s latitude/longitude is about 39.53 degrees North, 119.82 degrees west. This will be written as 39.53, -119.82.
Why -119.82? This is because the earth is divided into 4 quadrants, known as hemispheres (north, south, east, west) with the nexus being at the intersection of the Equator and Prime Meridian. This point lies in the Atlantic Ocean off the coast of Africa. Latitudes north of the equator are positive, south of the equator are negative. Longitudes east of the prime meridian are positive, west are negative.
This is why Reno is at -119 degrees west. Be careful here, if you list Reno’s latitude/longitude at 39.53, 119.82, your point will be located somewhere in North Korea.
The age old question geographers have faced is: how to display a round object (the earth) on a flat surface?
The answer is Map Skew. Because the earth is round, displaying it on a flat surface is problematic and the result of this will be a skewed image. Take the above image as an example. This is a screenshot from Google earth of the entire world. You can’t see lines of latitude, but they are spaced further apart as you go north or south from the equator, creating skew. In this map, Greenland looks to be about the size of the continent of Africa. In reality, Greenland is about ¼ the size of Africa. More about this later…
The solution to map skew are map projections. Different map projections focus on different areas of the earth and attempt to represent these features accurately, thus eliminating skew. Many map projections exist including ones focused on the western hemisphere, north America, Nevada, Nevada West, and so on.
A note about map projections in ArcGIS: Getting data to display in the same map projection is sometimes easier said than done. Quite commonly, you gather data from different sources. This data will be in different map projections and when imported into your map document, it won’t line up where is should be in the rest of the data. Fear not, this is a fixable problem. The issue is probably that your new data is projected differently from the existing data in your map document.
As I was saying, you are probably looking at skewed maps without even knowing it. Take a look at this website (www.thetruesize.com) and play with it. Type a county or state into the search box and then drag it north or south of the equator to see how big it really is.
Take the Greenland example from the previous slide. Choose Greenland as your country, then drag it to overlay with Africa. Here you will see the true size of Greenland compared to Africa.
You have objects represented as layers on your map. But the real power in your objects lies in the data associated with those objects. These are stored in the attribute table. Just like a spreadsheet, data is organized into rows and columns. An attribute table can have thousands of rows and columns. I assume this is a limit, but I have never reached it. As you can see in the above example, there are 7 objects represented as points. The attribute table is shown which contains various data fields (columns) for each object. You can use the data in the layer’s attribute table to manipulate it, pair it down, expand upon, etc.
Just like any project, GIS projects follow a workflow. Once you have decided what it is you want to analyze, you must gather the available data. Often times this is the most difficult or most time consuming part of the project! The analysis is the easy part (or usually less time consuming). Data can be gathered from various sources which usually needs massaging and editing to get everything to line up in the same format. Today, online data repositories, often provided by government agencies provide data. This is often municipal data such as census tracts, public utilities, or aerial imagery. Or maybe your agency already has previously used datasets ready to go? Remote sensing data is available online, which is are usually satellite images taken from space. Sometimes historic maps or documents can be digitized or scanned to reveal information. Often times data has to be gathered yourself. I have done this by hand with a GPS unit, taking coordinates and later adding these into ArcMap. Other times, the data is out there but is sitting on someone’s hard drive or server. Sometimes you get hint of this data via word of mouth or sometimes by asking contact people the data you need might surface. This method is hit or miss at best.