Hardware: Computers, GPS devices, servers, and other tools used to collect, process, and display spatial data. Software: Programs like ArcGIS, QGIS, ERDAS Imagine, etc., used for processing and analyzing spatial data. Data: Spatial Data (location information like coordinates, maps, satellite images) Attribute Data (descriptive information about features, such as population, land use) People: GIS users who collect data, run analysis, and interpret the results. Methods: Rules, procedures, and models used in GIS analysis to solve problems or answer questions.

1. Basics of GIS
Professor Dr Md Shahedur Rashid
Jahangirnagar University
m.s.rashid@juniv.edu

2. GIS--What is it?
• Geographic/Geographical/Geospatial
Information
– information about places on the earth’s surface
– knowledge about “what is where when”
– Geographic/geospatial: almost synonymous
• GIS--what’s in the S?
– Systems: technology oriented
– Sciences: concepts and theory
– Studies: applications of GIS
– Society: movement and awareness building
– Service: fulfilling the GIS related public needs

3. 3
A flow diagram of the DIKW
hierarchy; where d : data,
i : information, k : knowledge,
u : understanding, w : wisdom,
t : tacit knowledge, and
e : explicit knowledge
http://en.wikipedia.org/wiki/DIKW_Pyramid#/media/File:DIKW.png
DIKW MODEL : Status of Information

4. Defining Geographic Information Systems
(GIS)
• The common ground between information
processing and the many fields using spatial
analysis techniques. (Tomlinson, 1972)
• A powerful set of tools for collecting, storing,
retrieving, transforming, and displaying spatial
data from the real world. (Burroughs, 1986).

5. A GIS integrates five basic
components
data
methods
software
people
hardware

6. Data

7. Data - Data - Data
We all ‘got data’
• Location Data
– How Many – What Kind – Where
• Scale of Data
– Local to Global
• Data Presentation
– Words, Charts, Graphs, Tables, or Maps
• Exploring data using GIS turns data into
information into knowledge

8. Database
“Not Easy to Interpret”

9. Visualization
“Worth a Thousand Words”

10. • Raster – Grid
– “pixels”
– a location and value
– Satellite images and aerial
photos are already in this
format
• Vector – Linear
– Points, lines & polygons
– “Features” (house, lake, etc.)
• Attributes
– size, type, length, etc.
Real world
Two Ways to Input and Visualize Data
The World in GIS

11. Combining Data From Many Sources

12. Data For GIS Applications
• Digitized and Scanned Maps
– purchased, donated, free (Internet)
– created by user
• Data Bases – Tables of data
• GPS – Global Positioning System
– accurate locations
• Field Sampling of Attributes
• Remote Sensing &
Aerial Photography

13. “Spatial Analysis” – not just a map
Turning Data Into Information

14. Asking A Question – Interaction

15. Maps and Database are
“Interactive”

16. Multiple Databases can be
Linked and Related

17. Data vs.
Information
• Data, by itself, generally differs from
information.
• Data is of little use unless it is transformed
into information.
• Information is an answer to a question
based on raw data.
• We transform data into information
through the use of an Information System.

18. Types of datasets
Vector formats
(“feature classes”)
Points
Lines (”arcs”)
Polygons

19. Types of datasets
Raster formats
Matrices of square
cells (grids, pixels)

20. Types of datasets
Attribute tables:
tables of data describing
spatial features

27. Methods

28. Basic GIS Functions
Capture
Store
Query
Analyze
Display
Output

29. Capturing data
Paper maps
Digital images
GPS output
Coordinate lists

30. Query
Identifying specific features
Where is parcel No. 2945?
Identifying
features based
on conditions
Find all trees with DBH > 35 cm

31. Analysis
Proximity : which roads are within a 100 ft
from a stream
Overlay: combines the features of two or
more layers to create a new layer
(intersections, unions…)
Network: examines how linear features are
connected

32. Analysis

33. Analysis

34. Display
• Maps
• Graphs
• Reports/Tables

35. Examples of GIS maps
surface drapes & 3-D modeling

36. Examples of GIS generated maps
detailed
topographic maps

37. What GIS Applications Do:
manage, analyze, communicate
• make possible the automation of activities involving
geographic data
– map production
– calculation of areas, distances, route lengths
– measurement of slope, aspect, viewshed
– logistics: route planning, vehicle tracking, traffic
management
• perform complex spatial modelling (what if scenarios for
transportation planning, disaster planning, resource
management, utility design)

38. Why Study GIS?
• 80% of local government activities estimated to be geographically based
– plats, zoning, public works (streets, water supply, sewers), garbage collection, land
ownership and valuation, public safety (fire and police)
• a significant portion of state government has a geographical component
– natural resource management
– highways and transportation
• businesses use GIS for a very wide array of applications
– retail site selection & customer analysis
– logistics: vehicle tracking & routing
– natural resource exploration (petroleum, etc.)
– precision agriculture
– civil engineering and construction
• Military and defense
– Battlefield management
– Satellite imagery interpretation
• scientific research employs GIS
– geography, geology, botany
– anthropology, sociology, economics, political science
– Epidemiology, criminology

39. The major areas of GIS application
• Local Government
– Public works/infrastructure management (roads, water, sewer)
– Planning and environmental management
– property records and appraisal
• Real Estate and Marketing
– Retail site selection, site evaluation
• Public safety and defense
– Crime analysis, fire prevention, emergency management, military/defense
• Natural resource exploration/extraction
– Petroleum, minerals, quarrying
• Transportation
– Airline route planning, transportation planning/modeling
• Public health and epidemiology
• The Geospatial Industry
– Data development, application development, programming

40. Examples of Applied GIS
• Urban Planning, Management & Policy
– Zoning, subdivision planning
– Land acquisition
– Economic development
– Code enforcement
– Housing renovation programs
– Emergency response
– Crime analysis
– Tax assessment
• Environmental Sciences
– Monitoring environmental risk
– Modeling stormwater runoff
– Management of watersheds,
floodplains, wetlands, forests, aquifers
– Environmental Impact Analysis
– Hazardous or toxic facility siting
– Groundwater modeling and
contamination tracking
• Political Science
– Redistricting
– Analysis of election results
– Predictive modeling
• Civil Engineering/Utility
– Locating underground facilities
– Designing alignment for freeways, transit
– Coordination of infrastructure maintenance
• Business
– Demographic Analysis
– Market Penetration/ Share Analysis
– Site Selection
• Education Administration
– Attendance Area Maintenance
– Enrollment Projections
– School Bus Routing
• Real Estate
– Neighborhood land prices
– Traffic Impact Analysis
– Determination of Highest and Best Use
• Health Care
– Epidemiology
– Needs Analysis
– Service Inventory

41. Projection, Scale, Accuracy and Resolution
the key properties of spatial data
• Projection: the method by which the curved 3-D surface of the
earth is represented by X,Y coordinates on a 2-D flat map/screen
– distortion is inevitable
• Scale: the ratio of distance on a map to the equivalent distance
on the ground
– in theory GIS is scale independent but in practice there is an implicit range of
scales for data output in any project
• Accuracy: how well does the database info match the real world
– Positional: how close are features to their real world location?
– Consistency: do feature characteristics in database match those in real world
• is a road in the database a road in the real world?
– Completeness: are all real world instances of features present in the database?
• Are all roads included.
• Resolution: the size of the smallest feature able to be recognized
– for raster data, it is the pixel size
The tighter the specification, the higher the cost.

42. Thanks for Patience