[gdal-dev] gdal to define projection, EPSG:3412
John Callahan
john.callahan at UDel.Edu
Tue Nov 10 15:00:58 EST 2009
Is it possible to define/set a coordinate system using GDAL? I
downloaded some data (from NSIDC) I know is in EPSG:3412.
(http://spatialreference.org/ref/epsg/3412/,
http://nsidc.org/data/atlas/epsg_3412.html)
The data is in bsq format, therefore requires a hdr file that I've been
piecing together manually. The hdr file has a "projection info" line
that defines the projection parameters. Here is the hdr file I've been
using, unsuccessfully:
ENVI
description = {
File Imported into ENVI.}
samples = 316
lines = 332
bands = 1
header offset = 300
file type = ENVI Standard
data type = 1
interleave = bsq
sensor type = Unknown
byte order = 0
map info = {NSIDC Sea Ice Polar Stereographic South, 1.0000, 1.0000,
-3950000.0000, 4350000.0000, 2.5000000000e+004, 2.5000000000e+004,
Hughes 1980, units=Meters}
projection info = {31, 6378273.0, 6356889.4, -70.000000, 0.000000, 0.0,
0.0, Hughes1980, NSIDC Sea Ice Polar Stereographic South, units=Meters}
wavelength units = Unknown
pixel size = {2.50000000e+004, 2.50000000e+004, units=Meters}
The data displays properly with other vector data in EPSG:3412, say in
QGIS. To me, this simply means the "map info" line of correct.
However, when I try to project the data (gdal_translate, gdalwarp), the
output is nonsense (nearly all null or nodata). I believe my
"projection info" line is wrong, and may have something to do with
denoting the lat of origin as -90 and standard parallel as -70. Thanks
for any help.
- John
**************************************************
John Callahan, Geospatial Application Developer
Delaware Geological Survey, University of Delaware
URL: http://www.dgs.udel.edu
**************************************************
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