Changes between Version 6 and Version 7 of MultipleProjectionsJonathan


Ignore:
Timestamp:
02/08/07 13:52:34 (13 years ago)
Author:
russ
Comment:

Adding an explanation responding to Jonathan's comment.

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  • MultipleProjectionsJonathan

    v6 v7  
    77So I think the conciseness of this proposal comes at too high a cost, the acceptance of a new specialized syntax for grouping items in a list.
    88
    9 --Russ
     9''Russ''
    1010
    1111Proposal No 1 retains the grid mapping as an attribute of the data
     
    3131
    3232''Jonathan''
     33
     34Jonathan is right that the proposed syntax is similar to the syntax for formula_terms and cell_methods, but I think in these grid_mapping Proposals there is a crucial difference.  For formula_terms, the values are always of the form "term: variable", where the second element, variable, is the name of a netCDF variable.  For cell_methods, the values are of the form "name: method", where the second element, method, is selected from a specified list (in Appendix E of the current CF Conventions).  But in Proposal 1, the projection name such as "EPSG19914" is neither the name of a variable nor necessarily taken from a specified list in the CF Conventions, but is rather a name chosen by the data provider, perhaps from a large list of externally maintained projection names that might contain blanks, colons, or other special symbols, making parsing the grid_mapping attribute string potentially problematical.  Perhaps I have misunderstood, or we would need to be explicit about requiring that the projection name be a simple name with no special characters that might cause parsing problems.
     35
     36''Russ''