Using Map Projections with MapServer

The projection settings in a MapServer map file are at two levels: the output map projection and the projection of the input layers of features to be drawn. Example A-1 shows a sample of the projection settings for an output map.

Example A-1. Example settings for the map to be rendered using an Albers Equal Area projection
PROJECTION
  "proj=aea"
  "ellps=WGS84"
  "lat_0=10"
  "lon_0=-90"
END

The settings may look confusing to anyone unfamiliar with projections, but they have a straightforward purpose. If you can get these four settings clear in your mind, you’ll be able to handle most projections with ease.

The first line in Example A-1, "proj=aea", is the most ...

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