[Mapserver-users] Deriving TIGER extents

Frank Warmerdam warmerdam@pobox.com
Thu, 20 May 2004 00:38:57 -0400


> Any suggestions?
> 
> -- Marvin Humphrey

> EXTENT -91 41 -81 48
> #Longitude: 82° 26' W to 90° 31' W
> #Latitude: 41° 41' N to 47° 30' N
> 
> LAYER
>     NAME "tigertest"
>     TYPE line
>     CONNECTIONTYPE OGR
>     CONNECTION "../TGR26049"
>     DATA "CompleteChain"
>     STATUS ON
> END

Marvin,

First, don't you need a CLASS statement in your line layer to define
how to draw the lines?  Something like:

LAYER
     NAME "tigertest"
     TYPE line
     CONNECTIONTYPE OGR
     CONNECTION "../TGR26049"
     DATA "CompleteChain"
     STATUS ON
     CLASS
       COLOR 255 0 0
     END
END

Perhaps there is some reasonable default I don't know about.

Second, I don't have any problem getting extents from ogrinfo when
I specify a spatial layer (such as CompleteChain).  For example:


warmerda@gdal2200[108]% ogrinfo -ro -summary . CompleteChain
INFO: Open of `.'
using driver `TIGER' successful.

Layer name: CompleteChain
Geometry: Line String
Feature Count: 34768
Extent: (-121.560168, 34.543146) - (-80.859591, 45.118070)
Layer SRS WKT:
GEOGCS["NAD83",
     DATUM["North_American_Datum_1983",
         SPHEROID["GRS 1980",6378137,298.257222101]],
     PRIMEM["Greenwich",0],
     UNIT["degree",0.0174532925199433]]
MODULE: String (8.0)
TLID: Integer (10.0)
SIDE1: Integer (1.0)

In the above case there were a few random counties from around the country
in the directory so the extents are large, but if you only provide one county
is should be the appropriate country extents.

Good luck,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam@pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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