[gdal-dev] Question about gdal2wktraster

[Pierre Racine]

Jorge,

4267 should be the right CS (http://spatialreference.org/ref/epsg/4267/).

however, the bounding box seems different also. You should compare what bounding box you get using your driver with "SELECT astext(extent) FROM raster_columns" in PostGIS...

"SELECT astext(extent) FROM raster_columns" should match what you get from gdalinfo over the tif image.

Pierre

>-----Original Message-----
>From: gdal-dev-bounces at lists.osgeo.org [mailto:gdal-dev-bounces at lists.osgeo.org] On Behalf Of Jorge
>Arévalo
>Sent: 12 juillet 2009 19:01
>To: gdal-dev at lists.osgeo.org; PostGIS Development Discussion
>Subject: [gdal-dev] Question about gdal2wktraster
>
>Hello,
>
>Context: GDAL WKT Raster driver
>
>I've loaded the tif image
>ftp://ftp.remotesensing.org/geotiff/samples/gdal_eg/cea.tif on PostGIS
>using gdal2wktraster script using this line: gdal2wktraster.py -r
>cea.tif -t usa_mountain_one_band -s 4267 -b 1 -k 514x15 -I -M -o
>usa_raster_one_band.sql
>
>I used the srid 4267 because the information given for "gdalinfo
>cea.tif" (Maybe it is my error).
>
>The problem is: If I execute gdalinfo over the table created in
>PostGIS using my driver, I get this:
>
>(...)
>GEOGCS["NAD27",
>    DATUM["North_American_Datum_1927",
>        SPHEROID["Clarke 1866",6378206.4,294.9786982138982,
>            AUTHORITY["EPSG","7008"]],
>        AUTHORITY["EPSG","6267"]],
>    PRIMEM["Greenwich",0,
>        AUTHORITY["EPSG","8901"]],
>    UNIT["degree",0.01745329251994328,
>        AUTHORITY["EPSG","9122"]],
>    AUTHORITY["EPSG","4267"]]
>(...)
>Corner Coordinates:
>Upper Left  (  -28493.168, 4224973.000) (Invalid angle,Invalid angle)
>Lower Left  (  -28493.168, 4194061.600) (Invalid angle,Invalid angle)
>Upper Right (    2358.210, 4224973.000) (Invalid angle,Invalid angle)
>Lower Right (    2358.210, 4194061.600) (Invalid angle,Invalid angle)
>Center      (  -13067.479, 4209517.300) (Invalid angle,Invalid angle)
>(...)
>
>Look at "Invalid angle error". If I execute gdalinfo over the tif
>image, I get this:
>(...)
>PROJCS["unnamed",
>    GEOGCS["NAD27",
>        DATUM["North_American_Datum_1927",
>            SPHEROID["Clarke 1866",6378206.4,294.9786982138982,
>                AUTHORITY["EPSG","7008"]],
>            AUTHORITY["EPSG","6267"]],
>        PRIMEM["Greenwich",0],
>        UNIT["degree",0.0174532925199433],
>        AUTHORITY["EPSG","4267"]],
>    PROJECTION["Cylindrical_Equal_Area"],
>    PARAMETER["standard_parallel_1",33.75],
>    PARAMETER["central_meridian",-117.333333333333],
>    PARAMETER["false_easting",0],
>    PARAMETER["false_northing",0],
>    UNIT["metre",1,
>        AUTHORITY["EPSG","9001"]]]
>(...)
>Corner Coordinates:
>Upper Left  (  -28493.167, 4255884.544) (117d38'28.21"W, 33d54'13.08"N)
>Lower Left  (  -28493.167, 4224973.143) (117d38'28.21"W, 33d37'30.66"N)
>Upper Right (    2358.212, 4255884.544) (117d18'28.28"W, 33d54'13.08"N)
>Lower Right (    2358.212, 4224973.143) (117d18'28.28"W, 33d37'30.66"N)
>Center      (  -13067.478, 4240428.844) (117d28'28.24"W, 33d45'51.47"N)
>(...)
>
>The important thing is the "UNIT["metre",1,AUTHORITY["EPSG","9001"]]]
>part of the string that doesn't appear in my driver. For this reason,
>the transformation between utm (the original coords of the tif image)
>and lat,long doesn't take place. Then, the UTM coordinates are
>considered as invalid angles, of course.
>
>I think that my great mistake, as I said, was to choose 4267 as srid
>(I wasn't sure). Am I right? If yes, What srid should I use? If not,
>maybe the error is in my driver's code...
>
>Many thanks in advance
>Best regards,
>
>Jorge
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