Projection Determination and Visualization

A view of Projectionuesser in action.

Client: GreenInfo Network

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For people who use GIS, knowing the projection of a map is critical - otherwise features can show up hundreds or thousands of miles from their actual location. Most GIS data now comes with data about its projection, but sometimes it's missing or not quite clear. GreenInfo has developed a great (and fun) tool that can help solve these problems.

One of the joys of map making is getting a shapefile without a projection. GreenInfo staffer John Kelly eventually decided to stop doing those puzzles manually and wrote something that harnesses the power of PostGIS to try every single projection in its database.

Projectionuesser is the result. (Its name is a portmanteau of "projection" and "guesser.") After it paints the uploaded shapefile in every possible projection, the user pans and zooms to the expected correct location, clicks on the shape, and follows the link to the .prj file (in ArcGIS, the file that describes the actual projection). The tool does the heavy lifting of considering and visualizing every projection, but the geospatial analyst is the final arbiter of which projection is actually correct.

GreenInfo staffer John Kelly developed this project as an open source R+D tool, but we are no longer maintaining a running copy of the site. To try it out, you'll need download the code from GitHub and install your own copy.

Services: Interactive Solutions, GIS Services, Analysis, Data, Maps, Web Mapping

Tags: animation, GIS data, visualizations

Project Years: 2014