[Gdal-dev] Alabama geotiff tiles are showing up in Virginia
withinmapserver
John Mitchell
mitchelljj98 at gmail.com
Thu Feb 8 20:51:34 EST 2007
Ed,
Thanks for the information.
What should I use for the EPSG code when using mapserver or gdalwarp?
John
On 2/8/07, Ed McNierney <ed at topozone.com> wrote:
>
> John -
>
> Alabama East SPCS as EPSG:26929 is in units of meters, but your GeoTIFF
> seems to think it's in feet. This will cause the reprojection to move the
> file 3 times further from the CS origin than you think.
>
> It seems like you have a "hybrid" GeoTIFF with one projection definition
> and a different EPSG code.
>
> The ESRI-defined code of 102629 is an Alabama East NAD83 Feet projection.
> The definition is:
>
> # NAD 1983 StatePlane Alabama East FIPS 0101 Feet
> <102629> +proj=tmerc +lat_0=30.5 +lon_0=-85.83333333333333 +k=0.999960+x_0=200000 +y_0=0 +ellps=GRS80 +datum=NAD83 +to_meter=
> 0.3048006096012192 no_defs <>
>
> Which is identical to the 26929 definition except for the "to_meter"
> parameter.
>
> - Ed
>
> Ed McNierney
> President and Chief Mapmaker
> TopoZone.com / Maps a la carte, Inc.
> 73 Princeton Street, Suite 305
> North Chelmsford, MA 01863
> Phone: +1 (978) 251-4242
> Fax: +1 (978) 251-1396
> ed at topozone.com
>
> ------------------------------
> *From:* gdal-dev-bounces at lists.maptools.org [mailto:
> gdal-dev-bounces at lists.maptools.org] *On Behalf Of *John Mitchell
> *Sent:* Thursday, February 08, 2007 6:38 PM
> *To:* MAPSERVER-USERS at lists.umn.edu; Gdal-Dev
> *Cc:* mitchelljj98 at gmail.com
> *Subject:* [Gdal-dev] Alabama geotiff tiles are showing up in Virginia
> withinmapserver
>
> Hi,
>
> I have Alabama geotiff tiles which are showing up in Virginia within
> mapserver. If you look at the original gdalinfo against one of the tiles
> you will see that the corner coordinates are within Alabama, but within
> MapServer if you do on the fly projection(EPSG:26929 to EPSG:4326) it
> instead shows up within the state of Virginia. I also used gdalwarp to
> change the projection from EPSG:26929 to EPSG:4326 and then displayed within
> mapserver without having to reproject on the fly and it also shows up within
> Virginia. Note: when running gdalinfo on the gdalwarp file which was
> reprojected to EPSG:4326 it also has the coordinates within the state of
> Virginia.
>
> Below are the gdalinfo dumps first the original file and then the file
> that was converted from EPSG:26929 to EPSG:4326
>
> Driver: GTiff/GeoTIFF
> Size is 10000, 10000
> Coordinate System is:
> PROJCS["NAD83 / Alabama East",
> GEOGCS["NAD83",
> DATUM["North_American_Datum_1983",
> SPHEROID["GRS 1980",6378137,298.2572221010002,
> AUTHORITY["EPSG","7019"]],
> AUTHORITY["EPSG","6269"]],
> PRIMEM["Greenwich",0],
> UNIT["degree",0.0174532925199433],
> AUTHORITY["EPSG","4269"]],
> PROJECTION["Transverse_Mercator"],
> PARAMETER["latitude_of_origin",30.5],
> PARAMETER["central_meridian",-85.83333333333333],
> PARAMETER["scale_factor",0.99996],
> PARAMETER["false_easting",656166.6666666665],
> PARAMETER["false_northing",0],
> UNIT["US survey foot",0.3048006096012192,
> AUTHORITY["EPSG","9003"]],
> AUTHORITY["EPSG","26929"]]
> Origin = (723240.000000000000000,820340.000000000000000)
> Pixel Size = (0.500000000000000,-0.500000000000000)
> Metadata:
> AREA_OR_POINT=Area
> TIFFTAG_XRESOLUTION=72
> TIFFTAG_YRESOLUTION=72
> TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
> Corner Coordinates:
> Upper Left ( 723240.000, 820340.000) ( 85d36'54.59"W, 32d45'17.80"N)
> Lower Left ( 723240.000, 815340.000 ) ( 85d36'54.71"W, 32d44'28.33"N)
> Upper Right ( 728240.000, 820340.000) ( 85d35'56.04"W, 32d45'17.69"N)
> Lower Right ( 728240.000, 815340.000) ( 85d35'56.17"W, 32d44' 28.22"N)
> Center ( 725740.000, 817840.000) ( 85d36'25.38"W, 32d44'53.01"N)
> Band 1 Block=10000x1 Type=Byte, ColorInterp=Red
> Overviews: 1250x1250
> Band 2 Block=10000x1 Type=Byte, ColorInterp=Green
> Overviews: 1250x1250
> Band 3 Block=10000x1 Type=Byte, ColorInterp=Blue
> Overviews: 1250x1250
>
> -------------------------------------------------------------------------------------------------------------------
>
>
> Driver: GTiff/GeoTIFF
> Size is 11930, 9476
> Coordinate System is:
> GEOGCS["WGS 84",
> DATUM["WGS_1984",
> SPHEROID["WGS 84",6378137,298.2572235630016,
> AUTHORITY["EPSG","7030"]],
> AUTHORITY["EPSG","6326"]],
> PRIMEM["Greenwich",0],
> UNIT["degree",0.0174532925199433],
> AUTHORITY["EPSG","4326"]]
> Origin = (-79.902533251890048 ,37.745881181682833)
> Pixel Size = (0.000005030208747,-0.000005030208747)
> Metadata:
> AREA_OR_POINT=Area
> Corner Coordinates:
> Upper Left ( -79.9025333, 37.7458812) ( 79d54'9.12"W, 37d44'45.17"N)
> Lower Left ( -79.9025333, 37.6982149) ( 79d54'9.12"W, 37d41'53.57"N)
> Upper Right ( -79.8425229, 37.7458812) ( 79d50'33.08"W, 37d44'45.17"N)
> Lower Right ( -79.8425229, 37.6982149 ) ( 79d50'33.08"W, 37d41'53.57"N)
> Center ( -79.8725281, 37.7220481) ( 79d52'21.10"W, 37d43'19.37"N)
> Band 1 Block=256x256 Type=Byte, ColorInterp=Red
> Band 2 Block=256x256 Type=Byte, ColorInterp=Green
> Band 3 Block=256x256 Type=Byte, ColorInterp=Blue
>
>
> --
> John J. Mitchell
>
--
John J. Mitchell
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