GIS

GEOGRAPHIC INFORMATION SYSTEMS

An Overview

Thomas ReynoldsCSI668

May 7, 2001

What Is GIS ?

• Automated Systems, for the• Capture,• Storage, • Retrieval, • Analysis, and • Display• of Spatial Data

Spatial Data - What Where

• Streets, Houses, Trees, Schools, etc.• Water Lines, Sewer Pipes• Minerals, Oil, Aquifers, Soil Types• Telephone Lines, Electric Power Lines• Political Boundaries, Zip Codes• Mountains, Rivers, Lakes• Wildlife Habitat, Marketing Areas

Automated

• That's why we're here, right ?• Developed 1950's to Present• One Influence for Improving Graphics• Growth Curve Presently Steepening

Up• Databases, Processing, Displaying,

Communicating• May be Huge, Entirely Automated

Datasets – eg Satellite Images

(image from www.gisdatadepot.com/helpdesk/100k/ny100.jpg)

Some VocabularyLots of Acronyms

• Not just maps, "themes", the waterline – street – electric power line, etc. layers

• "RS" remote sensing• "GPS" global positioning systems• "GML" geographic markup language• "OGC" Open GIS Consortium• "AM/FM" automated mapping &

facilities management• "SVG" scalable vector graphics

Some More Basic Concepts

• Raster vs Vector• Topology• Projection• Registration• Geographic Reference• Geocode• So GIS != CAD

GIS:GIS: The Whole Picture

• A working GIS is an integrated whole of five components: hardware, software, data, personnel, and methods.

• Hardware can be big internet servers to standalone personal computers.

• Software ranges from multi-thousand dollar unix systems to free.

• Anything real is potential data.• People and methods make the rest

work.

TRAVEL TIMES

BLUE :

Shortest

GREEN :

Middle

MAGENTA :

Longest

______________

F : Fire Station

Tools, Products

• MapInfo www.mapinfo.com• ESRI www.esri.com• GRASS www.baylor.edu/grass• IDRISI www.idrisi.clarku.edu• TNT* www.microimages.com• Oracle

technet.oracle.com/products/spatial• Smallworld www.smallworld-us.com• Garmin www.garmin.com

(image from www.idrisi.clarku.edu/03PROD/gallery/Decrisk2.jpg)

Location Based Services - LBS

• Booming development• Traditional programming jobs, lots of java• People may talk about the global virtual

world of the internet, but the world is still a real, spatial one.

• Info exchange anywhere, everywhere• Built upon GIS, wireless, and the Internet• GIS provides and structures the

information• Wireless handles the communication

LBS

• You are your cell phone• What information is where you are, and

what information can come from somewhere else to you wherever you are?

• But 1st, where are you?• Need open standards--wherever you are,

your connectivity can transfer good info• The info itself must be structured so it

isn't hidden solely because not readable• And the info should include spatial

references

Maybe Not Utopia, Though

" 'Ubiquitous Geospatial Information' will empower individuals and nations to become better informed and act more intelligently for the good of all. It is a vision of the not too distant future that will improve the health, wealth, and security of individuals, communities, and nations around the globe."

( www.geojava.com/GettingStarted/tutorials/Ubiquitous-2.1.1.1.2.hmtl, 05/2001, no author shown )

What Makes This Possible?

• Java, the language of the Internet

• WAP, Wireless Application Protocol

• XML, Extensible Markup Language

• GML, Geography Markup Language

GML

• Based on XML• A simple text-based language that can

be understood anywhere• Can express relationships among geo-

spatial entities in one database or in databases distributed around the Internet

• Can be used to specify elements which can be interpreted to make maps

GML Mapmaking

(image from www.geojava.com/company/galdos/articles/GMLMapMaking_gml.htm)

GML Code

( from www.geojava.com/company/galdos/articles/GML3.htm)

<!-- ==============================================================global declarations [ from Schema www.opengis.net/namespaces/gml/core/feature.xsd ] ============================================================-- >. . .<!-- some basic geometric properties of features --><element name="_geometryProperty" type="gml:GeometryPropertyType" abstract="true"/><element name="geometryProperty" type="gml:GeometryPropertyType" /><element name="boundedBy" type="gml:BoundingShapeType"/>

<element name="pointProperty" type="gml:PointPropertyType" substitutionGroup="gml:_geometryProperty"/><element name="polygonProperty" type="gml:PolygonPropertyType" substitutionGroup="gml:_geometryProperty"/><element name="lineStringProperty" type="gml:LineStringPropertyType" substitutionGroup="gml:_geometryProperty"/><element name="multiPointProperty" type="gml:MultiPointPropertyType" substitutionGroup="gml:_geometryProperty"/> . . .<!-- common aliases for geometric properties --><element name="location" type="gml:PointPropertyType" substitutionGroup="gml:pointProperty"/><element name="centerOf" type="gml:PointPropertyType" substitutionGroup="gml:pointProperty"/><element name="position" type="gml:PointPropertyType" substitutionGroup="gml:pointProperty"/> . . .<element name="coverage" type="gml:PolygonPropertyType" substitutionGroup="gml:polygonProperty"/><element name="edgeOf" type="gml:LineStringPropertyType" substitutionGroup="gml:lineStringProperty"/><element name="centerLineOf" type="gml:LineStringPropertyType" substitutionGroup="gml:lineStringProperty"/> . . .

Further References

• www.geo.ed.ac.uk/home/giswww.html• www.albany.edu/~ls973/newmaps.html• www.opengis.org• www.tenlinks.com/MapGIS/products/

develop• www.geojava.com• spatialnews.geocomm.com/education• www.ccg.leeds.ac.uk/geotools• gis.about.com• www.geoplace.com