[Mapserver-users] Re: ogr broken perhaps? Problems with on-the-fly and other projections.

Andrew selkiesdad at twcny.rr.com
Thu May 27 06:07:39 EDT 2004

The coordinate shifts in the projected shape file after using ogr2ogr 
compared to the correct region settings are:

original lon/lat (-75.860047, 44.050400) - (-74.525683, 45.015850)
converted state plane (-406072.543743, -4299527.573525) - 
(-406071.208006, -4229526.607082)
Ref map base state plane (312000.0, 2092000.0) - (390000.0, 2168000.0)

lat lon comes from a UTM Zone 18N NAD83 GRS80 system (epsg:26918)
state plane is NY East zone (epsg:32115)

The projected shape file plots in the exact same location with the same 
size as the original lon/lat file if I change the associated PROJECTION 
block in the map file, so I assume the projection takes place.

Andrew wrote:

> I have been trying to get a latlong shapefile produced by the usgs 
> from a UTM dataset (grs80 nad83 zone 18N) to display on a raster layer 
> in NY State Plane East (epsg:32115) projection , map base projection 
> also set to epsg:32115. My failures have led me to reproject my data 
> manually using gdalwarp and ogr2ogr. I have confirmed the projections 
> by using ogrinfo, gdalinfo and by actively plotting the results. The 
> ogr utility (manual and on-the-fly) puts all my latlong points at 
> negative state plane coordinates at a very reduced scale and far off 
> "center" (by several region diameters). I have tried working with the 
> false eastings and northings, but with no luck. Gdal seems to get this 
> info (if it is needed) from the headers; rasters seem to project both 
> on the fly and manually, though I have to assemble more files and 
> templates to test this.
> I have tried TRANSFORM=TRUE and =ON, no luck (which is it, by the way? 
> both appear on the doc sites and in postings) and evrything else I can 
> think of or have seen posted.
> There is an old reference to version 3.3(something) being broken in 
> this regard.
> Any insights?
> Mapserve CGI mapserver 4.02 compiled from source on LINUX i86 
> Slackware kv 2.4.20

More information about the mapserver-users mailing list