Editing Geographic coordinate conversion (section)

=== Conversion across map projections ===

Conversion of coordinates and map positions among different map projections reference to the same datum may be accomplished either through direct translation formulas from one projection to another, or by first converting from a projection <math>A</math> to an intermediate coordinate system, such as ECEF, then converting from ECEF to projection <math>B</math>. The formulas involved can be complex and in some cases, such as in the ECEF to geodetic conversion above, the conversion has no closed-form solution and approximate methods must be used. References such as the ''DMA Technical Manual 8358.1''<ref name=TM8358.2>{{cite web|title=TM8358.2: The Universal Grids: Universal Transverse Mercator (UTM) and Universal Polar Stereographic (UPS)|url=http://earth-info.nga.mil/GandG/publications/tm8358.2/TM8358_2.pdf|publisher=National Geospatial-Intelligence Agency|access-date=4 March 2014|archive-date=3 March 2020|archive-url=https://web.archive.org/web/20200303184711/https://earth-info.nga.mil/GandG/publications/tm8358.2/TM8358_2.pdf|url-status=live}}</ref> and the USGS paper ''Map Projections: A Working Manual''<ref name=Snyder1987>{{cite book|last=Snyder|first=John P.|title=Map Projections: A Working Manual|year=1987|publisher=USGS Professional Paper: 1395|url=https://pubs.er.usgs.gov/publication/pp1395|access-date=2017-08-28|archive-date=2011-05-17|archive-url=https://web.archive.org/web/20110517082057/http://pubs.er.usgs.gov/publication/pp1395|url-status=live}}</ref> contain formulas for conversion of map projections. It is  common to use computer programs to perform coordinate conversion tasks, such as with the DoD and NGA supported GEOTRANS program.<ref name=GEOTRANS_NGA>{{cite web|title=MSP GEOTRANS 3.3 (Geographic Translator)|url=http://earth-info.nga.mil/GandG/geotrans/|publisher=NGA: Coordinate Systems Analysis Branch|access-date=4 March 2014|archive-date=15 March 2014|archive-url=https://web.archive.org/web/20140315075748/http://earth-info.nga.mil/GandG/geotrans/|url-status=live}}</ref>