Geospatial Web Dr. Harry Chen CMSC 491S/691S March 24, 2008

Agenda Digital maps revolution Introduction to GIS Key Geospatial Web technologies

Digital maps revolution

Introduction to GIS

Key Geospatial Web technologies

Our civilizations are built on maps Anglo-Saxon world map (circa 1040 CE) 1883 reconstruction of Eratosthenes ' map (276-194 BC) Babylonian World map (6 th Century BC) Tabula Peutingeriana (4th century) - Britain to the west, India to the East Source: http://en.wikipedia.org/wiki/Ancient_world_maps

Map is more than a piece of paper Map by itself is a technology Gives a virtual representation of an area Tells a story about of our past history Highlights the symbolic relationships between entities, objects and regions Cartography – the study of map-making

Map by itself is a technology

Gives a virtual representation of an area

Tells a story about of our past history

Highlights the symbolic relationships between entities, objects and regions

Cartography – the study of map-making

World Map 1970 Source: National Geographic Ukraine is part of the USSR

World Map 1994 Source: National Geographic Ukrain is no longer part of the USSR

Digital Maps Picture a digital map in your head. What do you see?

Do you see this? Fine. Google Maps is the most popular digital map today. But, there are many other kinds of digital maps before it. Without their innovations, we won’t have Google Maps.

Introduction to GIS

Disclaimer This is not a geography course lecture. This is not a cartography course lecture. This lecture is not intended to cover the full history or evolution of digital map making. It’s intended for software developers who want to learn geospatial web programming

This is not a geography course lecture.

This is not a cartography course lecture.

This lecture is not intended to cover the full history or evolution of digital map making.

It’s intended for software developers who want to learn geospatial web programming

Key concepts GIS (Geographic Information Systems) Geospatial Web

GIS (Geographic Information Systems)

Geospatial Web

GIS (Geographic Information Systems) No standard definition of what it is In general, it’s the use of computer systems to manage, analyze and display geographical information We use GIS to solve problems e.g., resource management and planning

No standard definition of what it is

In general, it’s the use of computer systems to manage, analyze and display geographical information

We use GIS to solve problems

e.g., resource management and planning

Geospatial Web No standard definition of what it is GIS for the Web : Use GIS technology to enhance Web application functions The Web for GIS : Use the Web as a platform for sharing geographic data, enabling collaboration and enriching the capabilities of GIS.

No standard definition of what it is

GIS for the Web : Use GIS technology to enhance Web application functions

The Web for GIS : Use the Web as a platform for sharing geographic data, enabling collaboration and enriching the capabilities of GIS.

Emergence of GIS Computing technology advancements helped to establish the GIS foundation Kind of like Paper Maps  Digital Maps Pen drawing  Click icons Statistical data on paper  Saved data in DB

Computing technology advancements helped to establish the GIS foundation

Kind of like

Paper Maps  Digital Maps

Pen drawing  Click icons

Statistical data on paper  Saved data in DB

Popular use of GIS Resource Management Asset Management Urban Planning Marketing Logistics Sales

Resource Management

Asset Management

Urban Planning

Marketing

Logistics

Sales

Technologies under the hood GIS Foundations Data entry Data display Data management (not covered) Information retrieval and analysis (not covered)

GIS Foundations

Data entry

Data display

Data management (not covered)

Information retrieval and analysis (not covered)

Data entry There’s the problem of data collection. But, we won’t discuss here. Let’s assume you have the data collected. How do you store this data? How would you store the information about the country border of Ukraine?

There’s the problem of data collection. But, we won’t discuss here.

Let’s assume you have the data collected.

How do you store this data?

How about the border of Indonesia? So many islands! Irregular shapes!

How about other kinds of data? Streets? Parcels? Evaluation? Land usage? Custom? restaurants that the Clintons has visited

Streets?

Parcels?

Evaluation?

Land usage?

Custom?

restaurants that the Clintons has visited

Some common representations Raster and Vector data The concept of layers (ESRI)

Raster and Vector data

What can say about your data? Geospatial data has two components (1) Observation (entity) (2) Attribute (variable) Country USA (entity) Population: 301,139,947 (variable) Capital: Washington, DC (variable)

Geospatial data has two components

(1) Observation (entity)

(2) Attribute (variable)

Country USA (entity)

Population: 301,139,947 (variable)

Capital: Washington, DC (variable)

What else can you say about data? Your data (i.e., entities) has two kinds of location information Absolute location The exact location in a coordinates system (lat/long) Relative location The topological location referred to other entities UMBC (entity) N 39° 15' 19'‘, W 76° 42' 41'‘ (absolute) Located in Baltimore County (relative)

Your data (i.e., entities) has two kinds of location information

Absolute location

The exact location in a coordinates system (lat/long)

Relative location

The topological location referred to other entities

UMBC (entity)

N 39° 15' 19'‘, W 76° 42' 41'‘ (absolute)

Located in Baltimore County (relative)

Data display Concerns how you want to look at the data for what purpose.

Concerns how you want to look at the data for what purpose.

Managing Your SimCity

Key Geospatial Web technologies

Geospatial Web technologies Languages for describing geospatial data on the Web Services for sharing and finding geospatial data on the Web Annotate Web resources with geospatial properties Visualizing the geospatial Web

Languages for describing geospatial data on the Web

Services for sharing and finding geospatial data on the Web

Annotate Web resources with geospatial properties

Visualizing the geospatial Web

GML Geography Markup Language (GML) is an XML language for expressing geographic features Defined by the Open Geospatial Consortium (OGC)

Geography Markup Language (GML) is an XML language for expressing geographic features

Defined by the Open Geospatial Consortium (OGC)

Describing a Feature using GML http://en.wikipedia.org/wiki/Geography_Markup_Language#Examples

KML Keyhole Markup Language An XML language for expressing geographical annotation and visualization. Developed by Keyhole, Inc. (which was later acquired by Google) Since GML is taken, I guess they have to stick with KML.

Keyhole Markup Language

An XML language for expressing geographical annotation and visualization.

Developed by Keyhole, Inc. (which was later acquired by Google)

Since GML is taken, I guess they have to stick with KML.

KML example KML is used by Google Maps and Google Earth Less expressive than GML in terms of kind of geographical information it can describe. But KML is more widely used in Web mashups.

KML is used by Google Maps and Google Earth

Less expressive than GML in terms of kind of geographical information it can describe.

But KML is more widely used in Web mashups.

Web Map Service (WMS) WMS is a specification for implementing a Web service that can dynamically produce maps of spatially referenced data Defined by OGC WMS Geo. Web Application Client Browser Map (JPEG, GIF etc.)

WMS is a specification for implementing a Web service that can dynamically produce maps of spatially referenced data

Defined by OGC

Web Feature Service (WFS) WFS is a specification for implementing a Web service that can produce descriptions of “Features” Feature is an abstract representation of any geospatial thing in the world. WFS Geo. Web Application Client Browser Feature (GML/XML or ESRI shapefiles)

WFS is a specification for implementing a Web service that can produce descriptions of “Features”

Feature is an abstract representation of any geospatial thing in the world.

Geotag There are many ways a user can annotate Web resources with location information. Flickr machine tags Microformats RDFa GeoRSS

There are many ways a user can annotate Web resources with location information.

Flickr machine tags

Microformats

RDFa

GeoRSS

Visualizing the geospatial Web 2D and 3D maps are changing the way we view information on the Web

2D and 3D maps are changing the way we view information on the Web

What’s next? We will visit the following topics Google Maps API GML and KML Geonames

We will visit the following topics

Google Maps API

GML and KML

Geonames