Changes between Version 48 and Version 49 of NetCDF_exportUpdateChanges

Timestamp:

Oct 17, 2011, 9:39:40 PM (13 years ago)

Author:

pds

Comment:

Adding notes about projection parameters - 2.

NetCDF_exportUpdateChanges

@@ -94 +94 @@
 A thorough analysis of the CF-1.5 map projections supported (see again [[http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.5/apf.html CF-1.5 App F]]) showed that the mapping of OGC WKT projection parameter names to CF-1.5 equivalents needed to be done per-projection. Whereas, the existing code tried to use a single global mapping of WKT attribute names to CF-1 for use in exporting.
 
-To overcome this issue we have defined per-projection mappings of OGC WKT parameter names to CF-1.5 equivalents using simple data structures, and re-written the NetCDF driver export code (in the CreateCopy() function) to reference these mappings when saving a map-projected raster.
-
-This was tested for all projections listed as part of CF-1.5 by translating input files in another format (eg GeoTIFF) into NetCDF, and then ensuring the resulting files were CF-compliant and could be opened as gridded data by the NetCDF Java API. 
+To overcome this issue we have defined per-projection mappings of OGC WKT parameter names to CF-1.5 equivalents using simple data structures, and re-written the NetCDF driver export code (in the CreateCopy() function) to reference these mappings when saving a map-projected raster. This approach is similar to that used for other drivers such as HFA and when exporting to ESRI PS strings.
+
+The updated code's projection capabilities was tested for all projections listed as part of CF-1.5 by translating input files in another format (eg GeoTIFF) into NetCDF, and then ensuring the resulting files were CF-compliant and could be opened as gridded data by the NetCDF Java API. 
 
 We also tested these files could have their projections correctly re-imported back into GDAL :- and in the process updated the NetCDF driver's projection import code (in !SetProjection()) as well.
 
-
+'''Note''': while we've tested the updated driver has much better coverage of CF-1.5 projection parameter handling than previously, there are still certain CF-1.5 projection unusual cases that are proving challenging to confirm an OGC WKT equivalent. We have documented this list at NetCDF_ProjectionTestingStatus, and welcome advice/testing on the remaining challenges here.
 
 ==== 3.2) When exporting to NetCDF map projections via GDAL, save projection coordinate variables. Optionally, also save lat and lon mapping variables. ====
@@ -232 +232 @@
 == Appendices/Links ==
 
-TODO - links to Wiki page with status of projection-handling by driver in development. Will be useful to point people to this, if interested to help with testing.
+ * wiki:NetCDF_ProjectionTestingStatus: page with information on tested capabilities to export from/to CF-1.5 projections.
+ * wiki:NetCDF_Improvements: community planning page for consolidating NetCDF driver upgrade suggestions that preceded the specific work described here.