Changes between Version 17 and Version 18 of NetCDF_exportUpdateChanges


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Timestamp:
Oct 5, 2011, 5:12:02 PM (13 years ago)
Author:
etourigny
Comment:

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  • NetCDF_exportUpdateChanges

    v17 v18  
    3333'''New -co options''': ?? Should we include an option to allow force assume south-regular?
    3434
    35 -> I don`t think so!
     35-> Definitely no!
    3636
    37 '''Has back-compat impact?''': Yes - since affects default import and export NetCDF behaviour.
    38 
    39 -> try to open a file with gdalinfo (version 1.8.1) and see if the bounds are ok, I think they should be ok, in which case there is no back-wards compatibility issue
    40 
    41 here is where upside-down is checked
    42 {{{
    43                 // Check for reverse order of y-coordinate
    44                 if ( yMinMax[0] > yMinMax[1] ) {
    45                     dummy[0] = yMinMax[1];
    46                     dummy[1] = yMinMax[0];
    47                     yMinMax[0] = dummy[0];
    48                     yMinMax[1] = dummy[1];
    49                 }
    50 }}}
    51 -> Try to create the file with and without custom gdal tags and see if both work.  thanks
     37'''Has back-compat impact?''': Only for GDAL versions prior to 1.6 (r18152).  Since then, a check is made to ensure the driver recognizes bottom-up grids and flips the y-axis accordingly.
    5238
    5339'''Change''':
    5440
    55 When GDAL exports to NetCDF, translate the data so that it is in "south up" orientation, i.e. invert the data from the GDAL default. Likewise upon import from CF-1, assume the data is in "south up" orientation, and translate the y values by default.
     41When GDAL exports to NetCDF, translate the data so that it is in "south up" orientation, i.e. invert the data from the GDAL default. Likewise upon import from CF-1, verify if the data is in "south up" orientation, and translate the y values by default.
    5642
    5743
    … …  
    7056
    7157Currently, as well as following the CF-1 conventions to save projection metadata, the NetCDF driver also writes metadata in several custom attributes:
    72  * A "spatial_ref" tag containing full OGC WKT string, including datum and EPSG codes if known
     58 * A "spatial_ref" tag containing full OGC WKT string, including datum and EPSG codes if known.
    7359 * A geotransform array, saved as a string (!GeoTransform).
    74 
    75 -> added a new proj4 string
     60 * Previously saved values of NN, SS, WE and WW are not saved any more (as they are incorporated into the geotransform array), although they are checked upon import for compatibility.
    7661
    7762The WRITEGDALTAGS driver creation option would allow the user to choose not to write these tags. However it would be set to 'YES' by default.
    … …  
    8671
    8772Note: In the longer-term we would view it as advantageous that the CF-1 conventions were augmented to allow recording of full datum information, and reduce the need to store extra CRS information in GDAL-managed attributes. However this will require agreement of the CF-1 community for a new standard, and would take time to agree upon and adopt.
     73
    8874=== Add saving of Datum reference Ellipsoid parameters in CF-1 compliant format, in addition to within GDAL's WKT ===
    8975