QUERY_TIFF is a method of obtaining information about a TIFF image file without having to read the file. See QUERY_* Routines for more information.
Result = QUERY_TIFF ( Filename [, Info] [, GEOTIFF=variable] [, IMAGE_INDEX=index] )
This routine returns a long with the value of 1 (one) if the query was successful (and the file type was correct) or 0 (zero) on failure.
A scalar string containing the pathname of the TIFF file to query.
Returns an anonymous structure containing information about the image in the file. The Info.TYPE field will return the value `TIFF'.
| Note |
Set this keyword to a named variable in which to return an anonymous structure containing the GeoTIFF tags and keys found in the file. If no GeoTIFF information is present in the file, the returned variable is set to a scalar zero. For a description of the possible GeoTIFF tags see the GEOTIFF keyword in READ_TIFF.
| Tip |
Image number index. If this value is larger than the number of images in the file, the function returns 0 (failure).
This is an example of using QUERY_TIFF to write and read a multi-image TIFF file. The first image is a 16-bit, single channel image stored using compression. The second image is an RGB image stored using 32-bits/channel uncompressed.
; Write the image data:
data = FIX(DIST(256))
rgbdata = LONARR(3,320,240)
WRITE_TIFF,'multi.tif',data,COMPRESSION=1,/SHORT
WRITE_TIFF,'multi.tif',rgbdata,/LONG,/APPEND
; Read the image data back:
ok = QUERY_TIFF('multi.tif',s)
IF (ok) THEN BEGIN
FOR i=0,s.NUM_IMAGES-1 DO BEGIN
imp = QUERY_TIFF('multi.tif',t,IMAGE_INDEX=i)
img = READ_TIFF('multi.tif',IMAGE_INDEX=i)
HELP,t,/STRUCTURE
HELP,img
ENDFOR
ENDIF
Introduced: 5.2
DESCRIPTION, DOCUMENT_NAME, DATE_TIME, and POSITION Info structures added: 6.1
GEOTIFF keyword added: 6.1
QUERY_* Routines, READ_TIFF, WRITE_TIFF