[Mapserver-users] List of mapservers

mapguy phatsbbnlist at twcny.rr.com
Thu May 20 16:55:08 EDT 2004

A question on TRANSFORM and related matters. ALL files verified as much 
as possible (`gdalinfo`, `ogrinfo` , GIS, etc):

I have some "init=epsg:26918"  (UTM 18N GRS80 NAD83) rasters  in  a tile 
and some "proj=latlong"  ( decimal degree ... derived from UTM NAD 83 
GRS80 I believe the metadata implies) data in a line shapefile. They 
plot perfectly.

I have "init=epsg:32115" (New York State Plane, Transverse Merc with 
false northings and eastings) rasters in a tile and the same shapefile 
as above, both in its original projection and in a state plane 
conversion using ogr2ogr.  Things don't seem so perfect.

The shape file is roughly 1/4 the size and 150 miles or so SW (3 region 
diameters essentially) of the place and size it should be, i.e. 
surrounding the tiled state plane rasters, and the associated quadrangle 
lines from plotting the tileindex shapefile as a vector layer. Either 
projection of the shape file works if I set the projection parameters 
correctly in the map file. Either disappears if I set the wrong projection.

the TRANSFORM doesn't seem to matter (though the online docs mention 
both "ON/OFF" and "TRUE/FALSE" in different places, and I tried both)

Is there a reasonable explanation as to why these files are plotting 
this way?  I mean, do false northings and eastings have to be added as 
PROJECTION block params, or something like that? Does/How does TRANSFORM 
work "on the fly", i.e. is there more to it than NOT putting TRANSFORM 
FALSE/OFF in a layer?

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