Web Mapping Illustrated

Create a Custom Application for a Particular Area

MapServer has many different settings you will want to learn more about as you develop your skills. A very small, core subset of options are used in the examples in this chapter. For a complete listing of map file settings, see the map file reference document at http://mapserver.gis.umn.edu/doc/mapfile-reference.html.

Also note that there are several MapServer CGI variables used in this chapter. For more information see the current MapServer CGI reference document at http://mapserver.gis.umn.edu/doc/cgi-reference.html.

Changing the Initial Extent of the Map

In Chapter 10 you learned how to change the extents of the map when using the shp2img command-line utility. With an interactive map the extents can be changed by zooming in, just like the test example with the global map application. The initial map shown by that application covers the whole world. If you are interested only in a map covering a certain area, you will want to change the initial extent of the map to suit your area of interest.

You will continue to build on the previous examples in this chapter, including the global.map file. The EXTENT line in the map file specifies what the initial extent of the map will be when MapServer starts up. This was set to:

EXTENT -180 -90 180 90

which covers the whole world. Now you will set this to zoom in to a new area, to make a map of Canada. You will do so by continuing to use the countries_simpl.shp shapefile, and also use the ogr2ogr ...