[mapserver-users] Starting with TIGER Line Data and MapServer

Stephen Woodbridge woodbri at swoodbridge.com
Tue Nov 3 12:40:30 EST 2009


Monali Lodha wrote:
> Thanks Stephen and Dan!
> 
> @Stephen
> The recent Tiger Shapefiles come with .prj files and do have a
> projection. Could there be a different issue then?

Mapserver does NOT look at the *.prj file. You have to do that yourself 
and set the PROJECTION ... END blocks appropriately in mapserver.

> @Dan
>> Regarding #1
>> Were all of your shapes in the same projection as the Itasca demo? If not, their coordinates may have been far outside of the extents of the map.
> Yes, we used the data for Itasca County.

SO you need to set the PROJECTION block in the MAP section AND each 
LAYER needs to have a PROJECTION block. The one in the MAP section 
defines the output projection to use and the ones in the LAYER define 
what the source data's projection is (these can be determinged from the 
*.prj file).

>> Regarding #2
>> Do you have 300 shapefiles, meaning you have 300 layers you wish to display?  If so, you might want to take a look at an alternate solution than the Itasca demo.  For example (toots own horn) GeoMOOSE is designed to allow multiple mapfiles to be used within a single application.   It makes the management of the large number of layers much more palatable.  We also have a number of users that are at the same level of layer management as you are and could give more suggestions on how to best manage that data for use in a Web GIS.
> 
> No. We have a few (10-15) layers. However, the shapefiles
> corresponding to each layer are different for every county. I shall
> also forward my query in the GeoMoose mailing list. Thanks!

Typically all county files for a given layer have identical structure in 
TIGER so you can group them together using a TILEINDEX in the mapfile.

-Steve


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