I have some data which are in geomagnetic coordinates; that is, they are latitude and longitude, but in reference to the magnetic north pole in Canada rather than the geographic north pole. As you might guess, I'd like to match them to other data which are in other coordinate systems.
(The data originated as a computation of the auroral oval; i.e., they originated as geomagnetic and there is no geographic source I could consult, even in principle.)
The data will be stored in PostGIS.
The easy way to do this is to find an EPSG code for the geomagnetic coordinate system, tag the data with that code, and then everything is magically reprojected to whatever I need at the time. However, I can't find any EPSG codes on spatialreference.org containing either geomagnetic or magnetic. Various Google searches also turn up nothing.
For the level of precision I need, any latitude/longitude coordinate system (e.g., WGS84) modified to have a different north pole is good enough. So if there's an easy way to define such a coordinate system and load it into PostGIS, that would be OK too.
For example, suppose that instead of converting from geomagnetic coordinates to geographic, I simply wanted to convert from UTM 15N to WGS84. I could save the UTM object into PostGIS unmodified, and tag it with the EPSG code 26915. Then, when I later made a query, I could say to PostGIS, "please return results in EPSG code 4326", and PostGIS would convert to WGS84 automatically.
Similarly, I would like to tag the geomagnetic data with some coordinate system and let PostGIS do the reprojection behind the scenes, without me having to call a
reproject() function manually.