[PROJ] Determine "cut line" for arbitrary projection

[Greg Troxel]

William Temperley via PROJ <proj at lists.osgeo.org> writes:

> Couldn't the cutlines be reasonably easily generated in geographic
> coordinates from either user-supplied or default projection
> parameters, using one of the above methods?
> An example for a derivable extent would be an orthographic projection where
> the cutline is just 90 degrees in spherical distance from the centre point.

A further question might be how the cutlines relate to the 'area of use'
in the EPSG database, but I'm afraid the answer is that the area of use
is a geodetic bounding box.  It does seem that a projection database
ideally would have this information.

But, as you point out with Mercator, that leads to Mercator-80 and
Mercator-85 entries, and that doesn't seem good.

Not sure this ended up being helpful, but wanted to mention the possible
relationship.