Transform from epsg:26912 to esri:102758 issue...

[Richard Greenwood]

Looks like it is just a matter of defining the false northing &
easting in feet versus meters. I think GDAL likes the  false northing
& easting in meters even from projections that are in feet. So nothing
looks out of order to me. But watch out for the US Survey Foot versus
the International Foot. ArcView didn't used to be to at
differentiating the two. Wyoming uses the US Survey Foot and the
correct value is +to_meter=0.3048006096012192

Rich
--
Richard Greenwood
richard.greenwood at gmail.com
www.greenwoodmap.com


On Thu, 9 Sep 2004 09:09:16 -0600, Jason M. Nielsen
<jnielsen at aero-graphics.com> wrote:
> This is more of a proj/gdal question but I cant seem to get through to the gdal
> mailing list so I thought perhaps someone on here might be able to lend a hand.
> I apologize if this is too off topic.
>
> I have data in epsg:26912 and the client wants it transformed to esri:102758.
>
> The destination system is "NAD-1983_Stateplane_Wyoming_West_FIPS_4904_Feet"
> according to ArcGIS.
>
> If I try to do a direct transformation the following occures:
>
> [root at mapserver s]# gdalwarp -s_srs epsg:26912 -t_srs esri:102758
> south_lincoln.tif south_lincolnx.tif
> ERROR 1: Translating source or target SRS failed:
> esri:102758
>
> So instead I have specified the parameters as follows:
>
> gdalwarp -s_srs epsg:26912 -t_srs "+proj=tmerc +lat_0=40.5
> +lon_0=-110.0833333333333 +k=0.999938 +x_0=799999.9999999999 +y_0=100000
> +ellps=GRS80 +datum=NAD83 +to_meter=0.3048006096012192" south_lincoln.tif
> south_lincolnx.tif
>
> Now this translates but I then have another issue. gdalinfo reports the
> following which looks all good accept one thing thats bugging me.  Note the
> false_easting and false_northing. The client gave me a print out of the
> projection defines which included those two values. I have also confirmed the
> clients printout in both ArcGIS and AutoCAD 2002. The false origin listed by the
> client is as follows:
>
> false_easting: 2624666.666667
> false_northing: 328083.333333
>
> Note that these are a factor of 3.2808 of those created during the gdal
> transformation below.
>
> [root at mapserver s]# gdalinfo south_lincolnx.tif
> Driver: GTiff/GeoTIFF
> Size is 21680, 42482
> Coordinate System is:
> PROJCS["unnamed",
>     GEOGCS["NAD83",
>         DATUM["North_American_Datum_1983",
>             SPHEROID["GRS 1980",6378137,298.2572221010042,
>                 AUTHORITY["EPSG","7019"]],
>             AUTHORITY["EPSG","6269"]],
>         PRIMEM["Greenwich",0],
>         UNIT["degree",0.0174532925199433],
>         AUTHORITY["EPSG","4269"]],
>     PROJECTION["Transverse_Mercator"],
>     PARAMETER["latitude_of_origin",40.5],
>     PARAMETER["central_meridian",-110.0833333333333],
>     PARAMETER["scale_factor",0.999938],
>     PARAMETER["false_easting",8611093.888888888],
>     PARAMETER["false_northing",1076386.736111111],
>     UNIT["US survey foot",0.3048006096012192,
>         AUTHORITY["EPSG","9003"]]]
> Origin = (2342073.330325,1150633.460539)
> Pixel Size = (3.28217146,-3.28217146)
> Corner Coordinates:
> Upper Left  ( 2342073.330, 1150633.461) (131d54'38.64"W, 38d36'4.93"N)
> Lower Left  ( 2342073.330, 1011200.253) (131d47'54.78"W, 38d14'45.11"N)
> Upper Right ( 2413230.808, 1150633.461) (131d40'45.89"W, 38d38'47.38"N)
> Lower Right ( 2413230.808, 1011200.253) (131d34'5.46"W, 38d17'25.51"N)
> Center      ( 2377652.069, 1080916.857) (131d44'20.54"W, 38d26'46.05"N)
>
> So the question is. Who's is correct? And if my output is wrong what am I doing
> incorrectly or are the defines in the esri proj file incorrect? Or am I bugging
> out over nothing?
>
> Thanks,
> Jason.
>