Pima County Department of Transportation

Geographic Information Services Division

Developing GIS for the Web

Methods for Publishing Spatial Data on the Internet

Map Generators

Map generation process:

• Map generators use a browser form. The user to enters specifications such as location, thematic layers and symbology on the form.
• The form is passed to the web server. A gateway at the web server passes the request to a GIS server. For instance, the gateway could pass the request in the form of AML to an ARC/INFO server. The ARC/INFO server generates a graphics file which is converted to GIF image.
• The GIF image is sent back to the client and viewed using native browser capability.

The advantage of map generators is creating custom maps on the fly. Disadvantages include lack of access to the raw spatial data, typically slower, limited predefined user choices, and involved setup. ARC/INFO is not designed for this medium.

Commercial, off-the-shelf solutions for GIS - WWW interfacing is a list of solutions that might fit into this category. GRID-Arendal Data and Information sources shows some of the source's work at the same web site.

Some of the following examples may access large enough databases or respond fast enough to put them in the next category of real time map browsers rather than map generators.

Examples of map generators:

• The U.S. Census Bureau's Tiger Mapping Service lets you build a map for any location in the US. You can even Request TMS maps directly from your own HTML web pages or CGI script. Use their service to build custom maps for your users on the fly. For instance: http://tiger.census.gov/cgi-bin/mapbrowse-tbl?&lon=-110.9&lat=32.2 generates up a browsable, customizable map of the Tucson area.
• University of Virginia SocialSciences Data Server.
• BADGER gives access to San Francisco Bay Area geo-data over the Internet, including vector data superimposed over scalable aerial images.
• The following all appear to be based on technology from Geosystems Global Corporation with data from Etak, Inc.
  • The Lycos search site offers Road Map which builds customized maps from addresses.
  • Maps On Us finds routes and displays maps with route instructions. Cool!
  • Bigbook can find businesses and display a map given any address.
  • MapQuest is an amazing interactive map and search facility.
  • Yahoo Maps is another, similar, map generator.
  • Netday96 allows you to zoom in on a pin map of participating schools until a text file describing participation at the school is displayed.
• TheWest Virginia Division of Environmental Protection has a GIS page with both a West Virginia GIS Data Repository and a WWW On-Line Interactive GIS Service.
• GIS-based Air Pollution Modeling on the WWW is a demonstration of a smokestack air pollution model. It accepts your input for smokestack parameters and generates contour map of concentrations by linking the web to ARC/INFO to do the analysis.
• The University of Adelaide in Austrailia has another interactive web interface to ARC/INFO, the Ecotourism Interactive GIS. You can select features to draw (zoom, pan etc), interrogate park and vegetation data (writes to a report window), connect from drawn map features to hypermedia information (via WWW hot links strategy), and produce an image file.
• Xerox PARC MapWeb Server
• The Verde River Watershed in Arizona offers Make O' Map.
• ForNet MapServer Software is a freely available system for generating and displaying maps interactively on the web. Some examples of its use are BWCAW Internet MapServer, Air Photos Online and Cooperative Stand Assesment. They also have an interactive image browser called ImageView.
• University of Virginia Library, Geographic Information Center: The Virginia County Interactive Mapper
• Demographic Data Viewer (DDViewer) from the Consortium for International Earth Science Information Network (CIESIN).