I have been using proj_factors() to get the meridian convergence for a
given point. It has been working great. We need this when projecting LiDAR
points that involve multiple rotations. The code is something like this:
PJ_FACTORS factors;
PJ_COORD vals;
vals.lp.lam = DegreesToRadians(point->LONGITUDE);
vals.lp.phi = DegreesToRadians(point->LATITUDE);
factors = proj_factors(tinfo->Meridian, vals);
return(RadiansToDegrees(factors.meridian_convergence));
I have been using it with Sweref99 (EPSG:4326).
I have two questions:
Is proj_factors() the fastest way to get this information? A look at the
code shows that it is calculating other things as well. Is there is a
faster way? When generating point clouds, each contains 10s of millions of
points, and we generated 10s of thousands of these over a summer. Needless
to say, we are always looking for speedups.
Would this method work for all 'standard' projections? By 'standard' I mean
the typical ones used in, say, European countries. Would we need to
consider anything when extending this to something other than EPSG:4326?
--
Roger Oberholtzer
_______________________________________________
PROJ mailing list
[email protected]
https://lists.osgeo.org/mailman/listinfo/proj
