The IDLffMrSID::GetProperty function method is used to query properties associated with the MrSID image.
Syntax
Obj->[IDLffMrSID::]GetProperty [, CHANNELS=nChannels] [, DIMENSIONS=Dims] [, LEVELS=Levels] [, PIXEL_TYPE=pixelType] [, TYPE=strType] [, GEO_VALID=geoValid] [, GEO_PROJTYPE=geoProjType] [, GEO_ORIGIN=geoOrigin] [, GEO_RESOLUTION=geoRes]
Arguments
None
Keywords
CHANNELS
Set this keyword to a named variable that will contain the number of image bands. For RGB images this is 3, for grayscale it is 1.
DIMENSIONS
Set this keyword equal to a named variable that will contain a two-element long integer array of the form [width, height] that specifies the dimensions of the MrSID image at level 0 (full resolution).
GEO_ORIGIN
Set this keyword to a named variable that will contain a two-element double precision array of the form [x, y] that specifies the location of the center of the upper-left pixel.
GEO_PROJTYPE
Set this keyword to a named variable that will contain an unsigned integer that specifies the geoTIFF projected coordinate system type code. For example, type code 32613 corresponds to PCS_WGS84_UTM_zone_13N.
For more information on the geoTIFF file type and available type codes see https://trac.osgeo.org/geotiff/.
GEO_RESOLUTION
Set this keyword to a named variable that will contain a two-element double precision array of the form [xres, yres] that specifies the pixel resolution.
GEO_VALID
Set this keyword to a named variable that will contain a long integer that is set to:
- 1 - If the MrSID image contains valid georeferencing data.
- 0 - If the MrSID image does not contain georeferencing data or the data is in an unsupported format.
Note: Always verify that this keyword returns 1 before using the data returned by any other GEO_* keyword.
LEVELS
Set this keyword equal to a named variable that will contain a two-element long integer array of the form [minlvl, maxlvl] that specifies the range of levels within the current image. Higher levels are lower resolution. A level of 0 equals full resolution. Negative values specify higher levels of resolution.
PIXEL_TYPE
Set this keyword to a named variable that will contain the IDL basic type code for a pixel sample. For a list of the data types indicated by each type code, see the “IDL Type Codes” section of the SIZE function.
TYPE
Set this keyword to a named variable that will contain a string identifying the file format. This should always be MrSID.
Examples
PRO MrSID_GetProperty
oFile = OBJ_NEW('IDLffMrSID', FILEPATH('test_gs.sid', $
SUBDIRECTORY = ['examples', 'data']))
oFile->GetProperty, CHANNELS = chan, LEVELS = $
lvls, Pixel_Type = pType, TYPE = fileType, GEO_VALID = geoQuery
PRINT, 'Number of image channels = ', chan
PRINT, 'Range of image levels = ', lvls
PRINT, 'Type code of image pixels = ', pType
PRINT, 'Image file type = ', FileType
PRINT, 'Result of georeferencing data query = ', geoQuery
OBJ_DESTROY, [oFile]
END
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