Changes between Version 3 and Version 4 of markhDataModelDraft


Ignore:
Timestamp:
02/17/14 06:52:52 (5 years ago)
Author:
markh
Comment:

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  • markhDataModelDraft

    v3 v4  
    1212The OGC Well Known Text (WKT) string is also supported within CF and may be used complementarily to entries in Appendix F to define a coordinate reference system.   The attribute '''crs_wkt''' must be used for WKT strings.  All uses of the '''crs_wkt''' attribute must be well formed well known text strings.
    1313
     14=== Derived Coordinate ===
     15
     16A derived coordinate links together explicit coordinate instances of a Field with a defined process for combining these to form a new coordinate.
     17
     18Each input coordinate is named and a derivation formula is provided.  At present derivation formulae are provided by named reference to [http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.6/apd.html Appendix D] and [http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.6/apf.html Appendix F] of the CF conventions for NetCDF files.
     19
     20These transform constructs correspond to the functions of the CF-netCDF attributes `formula_terms`, which describes how to compute a vertical auxiliary coordinate variable from components ([http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.6/cf-conventions.html#dimensionless-v-coord CF Appendix D]), and `grid_mapping`, which can describe how to compute true latitude and longitude auxiliary coordinate variables from horizontal projection dimension coordinates ([http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.6/cf-conventions.html#appendix-grid-mappings CF Appendix F]).