[CF-metadata] Example 5.10. British National Grid has wrong parameter names

From: John Caron <caron>
Date: Wed, 14 Mar 2012 17:57:05 -0600

Example 5.10. British National Grid

   int crs ;
     crs:grid_mapping_name = "transverse_mercator";
     crs:semi_major_axis = 6377563.396 ;
     crs:semi_minor_axis = 6356256.910 ;
     crs:inverse_flattening = 299.3249646 ;
     crs:latitude_of_projection_origin = 49.0 ;
     crs:longitude_of_projection_origin = -2.0 ;
     crs:false_easting = 400000.0 ;
     crs:false_northing = -100000.0 ;
     crs:scale_factor_at_projection_origin = 0.9996012717 ;


but Appendix F has:

Transverse Mercator
grid_mapping_name = transverse_mercator

Map parameters:
   scale_factor_at_central_meridian
   longitude_of_central_meridian
   latitude_of_projection_origin
   false_easting
   false_northing

I think we can presume that

   scale_factor_at_central_meridian == scale_factor_at_projection_origin
   longitude_of_central_meridian == longitude_of_projection_origin

central_meridian is probably clearer; so maybe just update the example ??

or we can add this amendment to ticket #75= "fix documentation and
definitions of 3 grid mapping definitions"
Received on Wed Mar 14 2012 - 17:57:05 GMT