[gdal-dev] Local coordinate system and proj4

[Martin Chapman]

Bryan,

Glad to hear it.  Attached is a zip file of the different Nevada state plane
definitions.  Maybe they will help as well.

Martin

-----Original Message-----
From: Bryan Keith [mailto:bryan at ideotrope.org] 
Sent: Wednesday, May 20, 2009 3:09 PM
To: Martin Chapman
Cc: gdal-dev at lists.osgeo.org
Subject: RE: [gdal-dev] Local coordinate system and proj4

Martin,

That did it.  It is in Nevada.  I don't know if it's a stateplane
coordinate system with an unusual false easting and northing or something
else.

I replaced "Local" with "Transverse_Mercator".  The reprojection worked. 
I compared the results with what ArcMap calculates, and the greatest
difference is < 1 cm.  That's good enough for what I'm doing.  Thank you
for the help.

Bryan

> Looks to me like it is a state plane projection for somewhere in Nevada.
> Maybe try using Transverse Mercator as the PROJCS.  I'm not a GIS pro
> though
> so take my advice with a grain of salt.
>
> Martin
>
> -----Original Message-----
> From: gdal-dev-bounces at lists.osgeo.org
> [mailto:gdal-dev-bounces at lists.osgeo.org] On Behalf Of Bryan Keith
> Sent: Wednesday, May 20, 2009 2:11 PM
> To: gdal-dev at lists.osgeo.org
> Subject: [gdal-dev] Local coordinate system and proj4
>
> Hello,
>
> I've been sent an ESRI coordinate system file (.prj) that looks like this:
>
>
PROJCS["Unknown",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984
>
",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.01745329
>
25199433]],PROJECTION["Local"],PARAMETER["False_Easting",68396.30349583333],
>
PARAMETER["False_Northing",207061.59375],PARAMETER["Scale_Factor",1.0],PARAM
>
ETER["Azimuth",0.0],PARAMETER["Longitude_Of_Center",-117.0],PARAMETER["Latit
> ude_Of_Center",41.29],UNIT["Foot_US",0.3048006096012192]]
>
> When I try to use this definition in proj4 using ogr tools, I get this
> error:
>
> ERROR 6: No translation for Local to PROJ.4 format is known.
>
> Is there a way to use this projection information with proj4?  ESRI ArcMap
> seems to be to translate from these coordinates to lat-long WGS84.
>
> Bryan
>
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>
>

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