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Web GISWeb Enabling VDOT's Roadway Network System GIS Data

April 6, 2009 David R RobisApril 6, 2009 David R Robis

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Agenda

• Virginia’s GIS Data Providers• Why not Google?• The Value of RNS• Internet Standards• Open Source Tools• System Architecture• Possible of Uses• Sample Web Interaction• Demo of LCAMS

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Virginia’s Data Providers

• Virginia Geographic Information Network (VGIN)– Offers a variety of geospatial products and

services to state agencies, local governments, non-profits, education and the private sector.

• VDOT Roadway Network System (RNS)– Incorporates a relational database that links

geo-spatial data and business attributes to the roadway centerlines.

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Why not Google?

• Licensing issues• Dependent on

external services• Provides only map

imagery• Cannot query

roadway or LRS data• Data updates at

Google’s discretion

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The Value of RNS

• Jurisdictional authorities• Route categorization• Edge measures• Intersections• Opposite routes• Master routes• Concurrency• Lane counts

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Internet Standards

• Geography Markup Language (GML)

• Styled Layer Descriptor (SLD)• Web Map Server (WMS)• Web Map Caching Server (WMS-C)• Web Feature Server (WFS)• Web Coverage Server (WCS)• Web Processing Server (WPS)

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Open Source Tools

• GeoServer– OGC Compliant WMS, WFS,

WCS, WMS-C– KML, GeoRSS, GeoJSON

• 52north– OGC Compliant WPS

• MetaCarta– OGC Compliant WMS-C

• PostGIS– Geospatial PostgreSQL

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System ArchitectureVAGIS Server

Post

GIS

Tile

C

ache

Apache httpd

Apache Tomcat

WMS-C

WFSW

MS

MetacatraTileCache

GeoserverServer

52northWPS ServerWPS

WFS

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Possible Uses

• Snap to route• Geo location to mile marker• Mile marker to geo location• Get containing county• Get nearest jurisdiction• Get nearest intersection• Get roadway segment by mile markers

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Sample Web Interaction

• On web-page load– WMS-C call(s) for map tiles. WMS called as needed

to generate tiles.• When a user clicks on the map

– WPS call to snap point to the route.– WPS call to get the LRS measure for the point.– WFS call to get the number of lanes at the point.

• On form submit– WPS call to get selected route geometry– Save geometry to the database

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Demo of LCAMS

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Questions

Contact Information:

David RobisonOpen Roads ConsultingChesapeake, VA(757) 546-3401David.Robison@openroadsconsulting.com