Changes between Version 48 and Version 49 of WKTRaster/SpecificationWorking03

Timestamp:

Apr 6, 2011, 7:04:08 AM (13 years ago)

Author:

Bborie Park

Comment:

—

WKTRaster/SpecificationWorking03

@@ -41 +41 @@
 '''ST_Band(raster, integer) -> raster''' -- the integer parameters are the band number of the rasters.[[BR]]
 Return a single band from a multiband raster. If "band" is greater than the value returned by ST_GetNumBands(), the function returns the last band. This function should be used to select a band before converting it to JPEG, TIFF, PNG, SVG or KML with the corresponding function. e.g. '''ST_AsTIFF(ST_Band(raster, band))
+
+'''Bborie: A complete implementation of ST_Band would include the following:
+
+ST_Band(rast raster, nbands int[]) -> raster
+
+    nbands is an array of 1-based band indices of the bands to copy into the output raster
+
+    Ex: For a raster rast with 3 bands:
+
+        ST_Band(rast, ARRAY[1,3,2])
+
+        ST_Band(rast, ARRAY[3,2,1])
+
+        You can rearrange the bands as above. You can also duplicate the bands:
+
+        ST_Band(rast, ARRAY[1,2,3,2,1])
+
+ST_Band(rast raster, nband int) -> raster
+
+    nband is a single integer of the 1-based band index of the band to copy into the output raster
+
+    Ex: ST_Band(rast, 1)
+
+        ST_Band(rast, 3)
+
+ST_Band(rast raster, nbands text) -> raster
+
+    nbands is a comma separated string of 1-based band indices indicating the bands to copy into the output raster
+
+    Ex: ST_Band(rast, '1,2')
+
+        ST_Band(rast, '1,2,3, 1, 1 , 2')
+
+ST_Band(rast raster) -> raster
+
+    the band to extract is automatically assumed to be one.
+
+    Ex: ST_Band(rast)
+
+If an index is outside the valid range of band indices for a raster (less than 1 or greater than the value returned by ST_NumBands), the function will fail and return.
+
+''' Open Question: ''' Should the function fail if an index is invalid?  How should this work when providing more than one indices to the function?
 
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