>>>>> Hamish <[EMAIL PROTECTED]> writes:
[...]
>> Reprojecting and subsetting of HDF-EOS grid data is, indeed,
>> straight-forward, and usually could be done with, e. g.,
>> gdalwarp(1). Not so for the swath data.
> Could the swath data be reprojected using gdalwarp's -tps thin plate
> spline function? ISTR that's what -tps was commisioned for. (??)
I've tried gdalinfo(1) on AIRS .hdf:
$ gdalinfo AIRS.2007.05.31.214.L2.RetStd.v4.0.9.102.D07281163221.hdf
and it shows no ground control points. I suppose, this is
because the GCP's are given in separate HDF arrays (Latitude &
Longitude), and not in the metadata. Solving this problem may
make gdalwarp(1) an alternative to HEG.
The one more problem with the MODIS L2 data is that it consists
of overlapping scans -- MODIS could ``see'' some parts of the
Earth in consequent scans. Like this (intended to be viewed
with a monospace font):
+--.... ....--+
| `~~~-----.... ....----~~~' |
| `~~~~~--------~~~~~' |
| |
| |
+--.... ....--+
|......`~~~-----.... ....----~~~'......|
|...................======--------======..................|
|......,...-----~~~' `~~~----..........|
+--~~~~ ~~~~--+
| |
| |
| ......--------...... |
| ,...-----~~~' `~~~----.... |
+--~~~~ ~~~~--+
(Areas filled with periods are the ones which MODIS ``sees''
twice per orbit.)
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