Terra GIS presents online list matching tool at the WA URISA Conference

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The WA URISA Conference was held April 23-25th, 2007 in
Lynnwood, WA. Karsten Vennemann gave a technical talk about the member list matching tool: “Building an online tool for spatial joins using open source software“. The following is the Abstract:

Most commercial GIS desktop software includes tools to spatially join information to a location. A spatial join operation adds information based on the geographical location of one feature to another. This talk illustrates how to build an online tool that can perform spatial joins using open source software. The technical solution presented can support any type of spatial join based on street address and a polygon layer and can be run on both Windows and Linux server platforms. For simplicity we will focus on providing a technical overview on how a web based tool can allow users with little or no GIS knowledge to attach legal district information for Washington State to their membership lists. The work order for the tool can be broken up into four main parts: 1) file upload to the server, 2) the retrieval and geocoding of the address records, 3) spatially matching the legal district information, and 4) the transfer of the information to the client computer. In step 1, the user uploads a text or Excel file via web interface onto the server. In step 2, the address records are read, and their geographic location (latitude/longitude) is determined by geocoding them against the 2006 Tiger line data of the US Census Bureau using PHP and Perl. In step 3, the legal district for each record is then spatially found running an SQL query against a PostGIS database. Finally, the tool streams the results to the client computer in form of a text or MS Excel file.

For more information about this tool please contact us. You can download the presentation slides here.