Version 7 (modified by edavis, 13 years ago) (diff)


Grid Mapping: Adding new grid mappings


Add new grid mappings to the existing list.


A number of grid mappings are being used that are not listed in CF. Make additions to the existing list.

This is a follow-up proposal to the proposal in CF Trac ticket #18.

Summary of Change

Add new grid mappings and required attributes.


  • Albers Conic Equal Area (EPSG 9822)
  • Azimuthal Equidistant (EPSG 9832)
  • Lambert Azimuthal Equal Area (EPSG 9820)
  • Lambert Conformal Conic (EPSG 9801 for one standard parallel, EPSG 9802 for two standard parallels)
  • Latitude-Longitude (???)
  • Polar Stereographic (EPSG 9810)
  • Rotated Pole
  • Stereographic (EPSG 9809)
  • Transverse Mercator (EPSG 9807)
  • Vertical Perspective (EPSG 9838, EPSG 9839 special case for view point height approaching or at infinity)

To be added:

  • Mercator (EPSG 9804 for one standard parallel, EPSG 9805 for two standard parallels)
  • Orthographic (EPSG 9840)


Allow existing data using non-CF defined grid mappings to be CF compliant.

Status Quo

CF compliant data using grid mappings that are not supported by CF.

Initial Statement of Technical Proposal

Add Examples to Appendix F


grid_mapping_name = mercator
Map parameters:
  • longitude_of_projection_origin
  • latitude_of_projection_origin
  • Either standard_parallel or scale_factor_at_projection_origin
  • standard_parallel
Map coordinates:

The x (abscissa) and y (ordinate) rectangular coordinates are identified by the standard_name attribute value projection_x_coordinate and projection_y_coordinate respectively.


Notes on using the PROJ.4 software packages for computing the mapping may be found at ("Mercator (1SP)" or EPSG 9804) or ("Mercator (2SP)" or EPSG 9805).