# Generate custom WKT Coordinate System definition from local / WGS84 pairs of coordinates [closed]

I am wondering if it possible to create a custom WKT for coordinate transformations based on pairs of WGS84 lat/lon and the corresponding local N/E values. So like a minimum 2 pairs?

If so is it possible to do with a tool (like pyproj/PROJ4/GeoPandas) and not a graphical tool.

• You need to know the transformation to use. With the known coordinates you may be able to find the parameters that better (minimum error) map your points trough the choosen transformation. – Gabriel De Luca Feb 7 at 16:28
• Not entirely sure what you are wanting to do. Could you provide a specific example? You could look into this: pyproj4.github.io/pyproj/latest/build_crs.html. However, it is a new feature that has not been released yet. Otherwise, you could use PROJ strings. – snowman2 Feb 8 at 1:49
• Well as is probably noticable, I am no surveyer but a programmer. It seems to me that it should be possible to calculate a custom WKT Projection if you know 2+ mappings from projected coordinates to geographic coordinates. At least if you know the center of the projection in geographic cordinates. I realize that a projected system needs to compensate for the spherical curve as conversions get further from the projection center, and that heights are a factor. Still I am curious if anybody has done work on this topic. – Jakob Simon-Gaarde Feb 8 at 8:42
• Are you talking about a conversion method in particular? What do you know about the function f that maps the coordinates from one system to another ((N,E) = f(lat,long))? Each projection, or conversion method, has a f function defined. That function has parameters that customize the projection. You need to know something about the relationship between both coordinate systems. Do you know the center of the projection and do you want to know if it is a Transverse Marcator or a Lambert Conformal Conical or something else? – Gabriel De Luca Feb 9 at 16:49
• Do you know that the local N/E system is a Transverse Mercator projection from the WGS84 ellipsoid and do you want to know its custom parameters? "It seems to me that it should be possible to calculate a custom WKT Projection if you know 2+ mappings from projected coordinates to geographic coordinates." - No, it is not possible. You need to know something more about the relationship between both coordinate systems. – Gabriel De Luca Feb 9 at 16:53