Version 8 (modified by edavis, 11 years ago) (diff) |
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Grid Mapping: Adding new grid mappings
Title
Add new grid mappings to the existing list.
Requirement
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.
Existing:
- 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)
Benefit
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
Mercator
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 - There may be 1 or 2 values.
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:
Notes on using the PROJ.4 software packages for computing the mapping may be found at http://www.remotesensing.org/geotiff/proj_list/mercator_1sp.html ("Mercator (1SP)" or EPSG 9804) or http://www.remotesensing.org/geotiff/proj_list/mercator_2sp.html ("Mercator (2SP)" or EPSG 9805).
Orthographic
grid_mapping_name = orthographic
Map parameters:
- longitude_of_projection_origin
- latitude_of_projection_origin
- false_easting
- false_northing
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:
Notes on using the PROJ.4 software packages for computing the mapping may be found at http://www.remotesensing.org/geotiff/proj_list/orthographic.html ("Orthographic" or EPSG 9840).