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- """
- PostGIS to GDAL conversion constant definitions
- """
- # Lookup to convert pixel type values from GDAL to PostGIS
- GDAL_TO_POSTGIS = [None, 4, 6, 5, 8, 7, 10, 11, None, None, None, None]
-
- # Lookup to convert pixel type values from PostGIS to GDAL
- POSTGIS_TO_GDAL = [1, 1, 1, 3, 1, 3, 2, 5, 4, None, 6, 7, None, None]
-
- # Struct pack structure for raster header, the raster header has the
- # following structure:
- #
- # Endianness, PostGIS raster version, number of bands, scale, origin,
- # skew, srid, width, and height.
- #
- # Scale, origin, and skew have x and y values. PostGIS currently uses
- # a fixed endianness (1) and there is only one version (0).
- POSTGIS_HEADER_STRUCTURE = 'B H H d d d d d d i H H'
-
- # Lookup values to convert GDAL pixel types to struct characters. This is
- # used to pack and unpack the pixel values of PostGIS raster bands.
- GDAL_TO_STRUCT = [
- None, 'B', 'H', 'h', 'L', 'l', 'f', 'd',
- None, None, None, None,
- ]
-
- # Size of the packed value in bytes for different numerical types.
- # This is needed to cut chunks of band data out of PostGIS raster strings
- # when decomposing them into GDALRasters.
- # See https://docs.python.org/library/struct.html#format-characters
- STRUCT_SIZE = {
- 'b': 1, # Signed char
- 'B': 1, # Unsigned char
- '?': 1, # _Bool
- 'h': 2, # Short
- 'H': 2, # Unsigned short
- 'i': 4, # Integer
- 'I': 4, # Unsigned Integer
- 'l': 4, # Long
- 'L': 4, # Unsigned Long
- 'f': 4, # Float
- 'd': 8, # Double
- }
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