Changes between Version 10 and Version 11 of Ticket #4522, comment 2


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Timestamp:
Apr 27, 2016, 8:46:36 AM (8 years ago)
Author:
thare

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  • Ticket #4522, comment 2

    v10 v11  
    33Anyway, back to main topic. This is not really a bug but a "feature".  There was a conscious decision for the PDS, ISIS2, ISIS3 (and probably VICAR), when a map projection is defined, to use it and always default to meters for the horizontal Cartesian coordinate system. Thus while indeed this file could be defined in "geocentric/geographic" using the defined "MAP_RESOLUTION = 4.0 <PIXEL/DEGREE>" (or 0.25 deg/pix) and the lat/lon ranges, there is also required keywords for "MAP_SCALE = 14.818 <KM/PIXEL>" and "MAP_PROJECTION_TYPE = SIMPLE CYLINDRICAL". PDS, ISIS2, and ISIS3 '''do not really allow''' for map projected products '''to be defined only in degrees'''. The label is required to also define the map projection and the pixel spacing in meters (or kilometers).
    44
    5 To be consistent across all map projected products, the current GDAL driver for these formats will default to using "MAP_SCALE" to gather the linear units (meters/kilometers) and try to map to an equivalent projection which for this MOLA product happens to map to "Equidistant Cylindrical". -Trent   
     5To be consistent across all map projected products, the current GDAL driver for these formats will default to using "MAP_SCALE" to gather the linear units (meters/kilometers) and try to map to an equivalent projection which for this MOLA product happens to map to "Equidistant Cylindrical".
     6
     7If degrees is really needed, it is pretty easy to override these defaults by using a VRT and changing the geotransform and map projection (SRS) definition to just define the body size. -Trent