[gdal-dev] gdalwarp: reprojecting HDF w/ Lat/Long metadata (GCP extraction)

[mattia]

Hello all

I would like to reproject (to WGS84) an HDF raster image dataset.
The problem is that I am not quite sure of what I should be using for the
GCP extraction and so which geographic data from within the HDF SDSs..
On tail with this email I have copied the output from gdalinfo on my main
HDF file containing multiple SDSs...

Do I need to use the Latitude/Longitude SDSs  (subdatasets 11, 12 ) from the
reprojection operations? Can anyone point me out on how I could possibly do
this as
to get a correctly georeferenced images? One which will not look like a
swath scanned image, but a skewed and correctly referenced one...

Hint: The image data covers a big part of China... hence, the reprojection
needs to take into account this... probably reprojecting onto WGS84 ??
Any suggestions would be appreciated...

Other problem is that out of the SDSs that I have, I would like to extract 8
bit raster images (from 16 bit unsigned ones in subdataset 0) ... Now, I
have been trying to approach this problem in different ways and still cannot
figure out which would be the best... Is it better to extract the SDS into a
separate HDF file first with hdp? Can I do the task by using hdftor8
directly?? By using gdal_translate for the first decomposition?? Any other
options ??

Best regards...

gdalinfo output:

Driver: HDF4/Hierarchical Data Format Release 4
Files: AMOD021KM20070104035343.hdf
Size is 512, 512
Coordinate System is `'
Metadata:

 GRINGPOINTLATITUDE.1=64.763542175293, 58.4916687011719, 20.8642158508301,
24.1079616546631
  GRINGPOINTLONGITUDE.1=91.4718399047852, 134.930770874023, 110.696083068848,
88.3426055908203

.... OTHER METADATA ....

  EASTBOUNDINGCOORDINATE=134.930768655651
  WESTBOUNDINGCOORDINATE=88.3307203917252
  NORTHBOUNDINGCOORDINATE=64.7989342568829
  SOUTHBOUNDINGCOORDINATE=20.7060304288409

.... OTHER METADATA ....

Subdatasets:
  SUBDATASET_1_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":0
  SUBDATASET_1_DESC=[15x4630x1354] EV_1KM_RefSB (16-bit unsigned integer)
  SUBDATASET_2_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":1
  SUBDATASET_2_DESC=[15x4630x1354] EV_1KM_RefSB_Uncert_Indexes (8-bit
unsigned integer)
  SUBDATASET_3_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":2
  SUBDATASET_3_DESC=[2x4630x1354] EV_250_Aggr1km_RefSB (16-bit unsigned
integer)
  SUBDATASET_4_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":3
  SUBDATASET_4_DESC=[2x4630x1354] EV_250_Aggr1km_RefSB_Uncert_Indexes (8-bit
unsigned integer)
  SUBDATASET_5_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":4
  SUBDATASET_5_DESC=[2x4630x1354] EV_250_Aggr1km_RefSB_Samples_Used (8-bit
unsigned integer)
  SUBDATASET_6_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":5
  SUBDATASET_6_DESC=[5x4630x1354] EV_500_Aggr1km_RefSB (16-bit unsigned
integer)
  SUBDATASET_7_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":6
  SUBDATASET_7_DESC=[5x4630x1354] EV_500_Aggr1km_RefSB_Uncert_Indexes (8-bit
unsigned integer)
  SUBDATASET_8_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":7
  SUBDATASET_8_DESC=[5x4630x1354] EV_500_Aggr1km_RefSB_Samples_Used (8-bit
unsigned integer)
  SUBDATASET_9_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":8
  SUBDATASET_9_DESC=[16x4630x1354] EV_1KM_Emissive (16-bit unsigned integer)
  SUBDATASET_10_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":9
  SUBDATASET_10_DESC=[16x4630x1354] EV_1KM_Emissive_Uncert_Indexes (8-bit
unsigned integer)
  SUBDATASET_11_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":10
  SUBDATASET_11_DESC=[926x271] Latitude (32-bit floating-point)
  SUBDATASET_12_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":11
  SUBDATASET_12_DESC=[926x271] Longitude (32-bit floating-point)
  SUBDATASET_13_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":12
  SUBDATASET_13_DESC=[926x271] Height (16-bit integer)
  SUBDATASET_14_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":13
  SUBDATASET_14_DESC=[926x271] SensorZenith (16-bit integer)
  SUBDATASET_15_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":14
  SUBDATASET_15_DESC=[926x271] SensorAzimuth (16-bit integer)
  SUBDATASET_16_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":15
  SUBDATASET_16_DESC=[926x271] Range (16-bit unsigned integer)
  SUBDATASET_17_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":16
  SUBDATASET_17_DESC=[926x271] SolarZenith (16-bit integer)
  SUBDATASET_18_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":17
  SUBDATASET_18_DESC=[926x271] SolarAzimuth (16-bit integer)
  SUBDATASET_19_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":18
  SUBDATASET_19_DESC=[926x271] gflags (8-bit unsigned integer)
  SUBDATASET_20_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":19
  SUBDATASET_20_DESC=[4630x1354] EV_Band26 (16-bit unsigned integer)
  SUBDATASET_21_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":20
  SUBDATASET_21_DESC=[4630x1354] EV_Band26_Uncert_Indexes (8-bit unsigned
integer)
  SUBDATASET_22_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":21
  SUBDATASET_22_DESC=[16x10] Noise in Thermal Detectors (8-bit unsigned
integer)
  SUBDATASET_23_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":22
  SUBDATASET_23_DESC=[16x10] Change in relative responses of thermal
detectors (8-bit unsigned integer)
  SUBDATASET_24_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":23
  SUBDATASET_24_DESC=[463x16x10] DC Restore Change for Thermal Bands (8-bit
integer)
  SUBDATASET_25_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":24
  SUBDATASET_25_DESC=[463x2x40] DC Restore Change for Reflective 250m Bands
(8-bit integer)
  SUBDATASET_26_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":25
  SUBDATASET_26_DESC=[463x5x20] DC Restore Change for Reflective 500m Bands
(8-bit integer)
  SUBDATASET_27_NAME=HDF4_SDS:UNKNOWN:"AMOD021KM20070104035343.hdf":26
  SUBDATASET_27_DESC=[463x15x10] DC Restore Change for Reflective 1km Bands
(8-bit integer)
Corner Coordinates:
Upper Left  (    0.0,    0.0)
Lower Left  (    0.0,  512.0)
Upper Right (  512.0,    0.0)
Lower Right (  512.0,  512.0)
Center      (  256.0,  256.0)

-- 
Mattia
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