[postgis-devel] Distance in Meters, not in projected units

[Nathaniel Hunter Clay]

Hi,

I am working on another modification ST_isVisible(raster dem,point a, 
point b), this would test visibility from A-->B. I am in need of a 
function that returns the distance from A-->B in meters regardless of 
the projection unit. Is there currently a safe way to do this? I am 
trying to avoid this: ST_isVisible(raster dem, point a, point b, double 
conversionFactor).

Thanks,

Nathaniel Hunter Clay