Changes between Version 4 and Version 5 of rfc14_imagestructure


Ignore:
Timestamp:
Nov 6, 2007, 7:46:55 PM (17 years ago)
Author:
warmerdam
Comment:

PIXEL_INTERPRETATION to PIXELTYPE. A bit of other cleanup.

Legend:

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  • rfc14_imagestructure

    v4 v5  
    2323   This only applies on datasets, and the value should be one of PIXEL, LINE or BAND.  It can be used as a data access hint.
    2424
    25  PIXEL_INTERPRETATION::
     25 PIXELTYPE::
    2626   This may appear on a GDT_Byte band (or the corresponding dataset) and have the value SIGNEDBYTE to indicate the unsigned byte values between 128 and 255 should be interpreted as being values between -128 and -1 for applications that recognise the SIGNEDBYTE type.
    2727
    … …  
    4242 2. The HFA driver will be updated to return NBITS metadata.
    4343 3. The HFA, GTiff, JP2KAK, ECW, JPEG, and PNG drivers will be updated to return INTERLEAVE metadata.
    44  4. The HFA and GTiff drivers will be updated to return PIXEL_INTERPRETATION metadata.
     44 4. The HFA and GTiff drivers will be updated to return PIXELTYPE metadata.
    4545
    4646The development will be done by Frank Warmerdam in trunk in time for GDAL/OGR 1.5.0 release.  Changes to other drivers that these definitions might be useful for while be done as time permits by interested developers - not necessarily in time for GDAL/OGR 1.5.0.
    … …  
    4848== Notes ==
    4949
    50 The gdalinfo utility already reports IMAGE_STRUCTURE metadata when it is available.
    51 
    52 Some work will also be done to make the GTiff, and HFA drivers CreateCopy() methods check the source for NBITS and PIXEL_INTERPRETATION metadata to create specialized output files types (NBITS already done for GTiff).
    53 
    54 == Concerns ==
    55 
    56 I'm really not sure PIXEL_INTERPRETATION is the right approach to pseudo-supporting a signed byte type as GDT_Byte.  It might be better to have drivers treat this data as GDT_Int16, and set NBITS to 8 as a special clue to the restricted nature of the data.
    57 
    58 I'm wondering if we should use COMPRESS instead of COMPRESSION and specify that this is the same keyword that should be used as a creation option for drivers offering compression.
     50* The gdalinfo utility already reports IMAGE_STRUCTURE metadata when it is available.
     51* The GTiff, and HFA drivers CreateCopy() methods check the source for NBITS, and PIXELTYPE metadata to create specialized output files types.
     52* The GTiff, HFA and default CreateCopy() implementations have been reworked to use the new GDALDatasetCopyWholeRaster() function which uses the INTERLEAVE metadata as a clue whether to do interleaved copies if the source dataset is interleaved.