[gdal-dev] gdalwarp problems with MODIS L1B

[Michael Sumner]

Hello, I'm having problems with gdalwarp-ing a MODIS L1B calibrated
radiance dataset.

This file contains 31 SDS subdatasets, the first two here are Latitude and
Longitude arrays and the third is the reflectance data EV_1KM_RefSB. The
geolocation arrays have a pixel and line for every fifth pixel/line in the
data

MOD021KM.A2012062.0455.006.2014220083128.hdf
SUBDATASET_20_NAME=HDF4_SDS:UNKNOWN:"MOD021KM.A2012062.0455.006.2014220083128.hdf":0
SUBDATASET_20_DESC=[406x271] Latitude (32-bit floating-point)
SUBDATASET_21_NAME=HDF4_SDS:UNKNOWN:"MOD021KM.A2012062.0455.006.2014220083128.hdf":1
SUBDATASET_21_DESC=[406x271] Longitude (32-bit floating-point)
SUBDATASET_22_NAME=HDF4_SDS:UNKNOWN:"MOD021KM.A2012062.0455.006.2014220083128.hdf":2
SUBDATASET_22_DESC=[15x2030x1354] EV_1KM_RefSB (16-bit unsigned integer)

By my reading of https://trac.osgeo.org/gdal/wiki/rfc4_geolocate that means
the Geolocation tag from gdalinfo should have a PIXEL_STEP and LINE_STEP of
5, and if I do this I get a much better result but it's still not right.
I've put a jpeg image of the result, with the coastline mapped and not
lining up, here:

http://staff.acecrc.org.au/~mdsumner/mod1.jpg

If I understand correctly, gdalwarp should be able to georeference this
with a simple call, optionally with tr, te, and t_srs values

gdalwarp infile out.tif

The t_srs I use is '+proj=laea +lon_0=60 +lat_0=-70 +ellps=WG84'.

 Here's the gdalinfo output for the EV_1KM_RefSB subdataset for the
relevant section:

gdalinfo HDF4_SDS:UNKNOWN:"MOD021KM.A2012062.0455.006.2014220083128.hdf":2
|  grep 'Geolocation:' -A 10
Geolocation:
  LINE_OFFSET=0
  LINE_STEP=1
  PIXEL_OFFSET=0
  PIXEL_STEP=1
  SRS=GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS
84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9108"]],AUTHORITY["EPSG","4326"]]
  X_BAND=1

X_DATASET=HDF4_SDS:UNKNOWN:"MOD021KM.A2012062.0455.006.2014220083128.hdf":1
  Y_BAND=1

Y_DATASET=HDF4_SDS:UNKNOWN:"MOD021KM.A2012062.0455.006.2014220083128.hdf":0
Corner Coordinates:

I get this file originally from here (136 Mb):

ftp://ladsweb.nascom.nasa.gov/allData/6/MOD021KM/2012/062/MOD021KM.A2012062.0455.006.2014220083128.hdf

I see this in 1.11.1 and 2.0.0beta1.

I have also attached the gdalinfo output in full here:

http://staff.acecrc.org.au/~mdsumner/gdalinfo_EV_1KM_RefSB.txt

cheers, Mike.
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