List of Routines By Functionality | MISR Toolkit: Main Page
-Abstract
MTK_READRAW returns 2-D array of MISR data given a file, grid, field, and region. The data return is
raw or native to the MISR product file/grid/field thus no unpacking, unscaling or interpreting is done.
The Mtk_ReadRaw routine always returns data on a MISR grid approximated by the region, no spatial
interpolation is performed (only block assembly). A map info structure is also return to provide
geolocation information to the Map Query routines. This routine is not typically used, instead use
Mtk_ReadData. See Particulars below regarding extra dimensions in some fields.
-Copyright
Copyright (2005), California Institute of Technology.
U.S. Government sponsorship acknowledged.
-I/O
Given:
filename MISR product file
gridname grid name
fieldname field name
region region structure
the call:
status = MTK_READRAW( filename, gridname, fieldname, region, databuf, mapinfo )
returns:
status 0 on success; otherwise failure
databuf 2-D data array
mapinfo map info structure
-Examples
;;
;; Set up input parameters
;;
filename = '../Mtk_testdata/in/MISR_AM1_GRP_ELLIPSOID_GM_P037_O029058_AA_F03_0024.hdf'
gridname = 'RedBand'
fieldname = 'Red Radiance/RDQI'
lat = 66.0
lon = -89.0
lat_extent = 1.5
lon_extent = 1.0
status = MTK_SETREGION_BY_LATLON_EXTENT( lat, lon, lat_extent, lon_extent, "degrees", region )
status = MTK_READRAW( filename, gridname, fieldname, region, databuf, mapinfo )
;;
;; Output...
;;
print, 'file : ', filename
print, 'grid : ', gridname
print, 'field : ', fieldname
print, '================================================='
help, databuf
help,/struct, mapinfo
IDL outputs:
file : ../Mtk_testdata/in/MISR_AM1_GRP_ELLIPSOID_GM_P037_O029058_AA_F03_0024.hdf
grid : RedBand
field : Red Radiance/RDQI
=================================================
DATABUF UINT = Array[448, 640]
** Structure <2867010>, 37 tags, length=1064, data length=1064, refs=1:
PATH LONG 37
START_BLOCK LONG 36
END_BLOCK LONG 37
RESOLUTION LONG 275
RESFACTOR LONG 1
NLINE LONG 640
NSAMPLE LONG 448
PIXEL_CENTER LONG 1
SOM_PATH LONG 37
SOM_ULC_X DOUBLE 12394112.
SOM_ULC_Y DOUBLE 1065762.5
SOM_CTR_X DOUBLE 12481975.
SOM_CTR_Y DOUBLE 1127225.0
SOM_LRC_X DOUBLE 12569838.
SOM_LRC_Y DOUBLE 1188687.5
GEO_ULC_LAT DOUBLE 66.950041
GEO_ULC_LON DOUBLE -89.380321
GEO_URC_LAT DOUBLE 66.451144
GEO_URC_LON DOUBLE -86.901382
GEO_CTR_LAT DOUBLE 66.001338
GEO_CTR_LON DOUBLE -89.003794
GEO_LRC_LAT DOUBLE 65.052256
GEO_LRC_LON DOUBLE -88.652965
GEO_LLC_LAT DOUBLE 65.523048
GEO_LLC_LON DOUBLE -91.031282
PP_PATH LONG 37
PP_PROJCODE LONG 22
PP_ZONECODE LONG -1
PP_SPHERECODE LONG 12
PP_PROJPARAM DOUBLE Array[15]
PP_ULC_BLOCK1 DOUBLE Array[2]
PP_LRC_BLOCK1 DOUBLE Array[2]
PP_NBLOCK LONG 180
PP_NLINE LONG 512
PP_NSAMPLE LONG 2048
PP_RELOFFSET FLOAT Array[179]
PP_RESOLUTION LONG 275
-Particulars
The MISR Toolkit read functions always return a 2-D data plane buffer. Some fields in the MISR data products
are multi-dimensional. In order to read one of these fields, the slice to read needs to be specified.
A bracket notation on the fieldname is used for this purpose. For example fieldname = “RetrAppMask[0][5]”.
Additional dimensions can be determined by the routine mtk_file_grid_field_to_dimlist() or by the
MISR Data Product Specification (DPS) Document. The actually definition of the indices are not described in the
MISR product files and thus not described by the MISR Toolkit. These will have to be looked up in the
MISR DPS. All indices are 0-based.
Example with 1-dimensional field:
filename = '../Mtk_testdata/in/MISR_AM1_AS_AEROSOL_P037_O029058_F09_0017.hdf'
gridname = 'RegParamsAer'
basefieldname = 'RegBestEstimateSpectralOptDepth'
lat = 66.0
lon = -89.0
lat_extent = 1.5
lon_extent = 1.0
status = MTK_FILE_GRID_FIELD_TO_DIMLIST(filename, gridname, basefieldname, ndim, dimnames, dimsizes)
print, ndim
print, dimnames
print, dimsizes
fieldname = 'RegBestEstimateSpectralOptDepth[1]'
status = MTK_SETREGION_BY_LATLON_EXTENT( lat, lon, lat_extent, lon_extent, "degrees", region )
status = MTK_READRAW( filename, gridname, fieldname, region, databuf, mapinfo )
status = MTK_READRAW( filename, gridname, basefieldname, region, databuf, mapinfo )
% MTK_READDATA: MISSING FIELD DIMENSION
Example with 2-dimensional field:
filename = '../Mtk_testdata/in/MISR_AM1_AS_AEROSOL_P037_O029058_F09_0017.hdf'
gridname = 'SubregParamsAer'
basefieldname = 'RetrAppMask'
lat = 66.0
lon = -89.0
lat_extent = 1.5
lon_extent = 1.0
status = MTK_FILE_GRID_FIELD_TO_DIMLIST(filename, gridname, basefieldname, ndim, dimnames, dimsizes)
print, ndim
print, dimnames
print, dimsizes
fieldname = 'RetrAppMask[0][5]'
status = MTK_SETREGION_BY_LATLON_EXTENT( lat, lon, lat_extent, lon_extent, "degrees", region )
status = MTK_READRAW( filename, gridname, fieldname, region, databuf, mapinfo )
status = MTK_READRAW( filename, gridname, basefieldname, region, databuf, mapinfo )
% MTK_READDATA: MISSING FIELD DIMENSION
-Required Reading
For important details concerning this module's function, please refer to
the MTK routine MtkReadRaw.c.
-Version
-IDL-MTK Version 1.2.0