> Orders of magnitude more than a web response That's likely where our different assesments come from, then. I was thinking more along the lines of "it's paral

> Orders of magnitude more than a web response That's likely where our different assesments come from, then. I was thinking more along the lines of "it's parallalelizable and easily offloaded to the client". An addendum for completeness' sake, though :) > What you're suggesting is that Not entirely. I'd build a LUT of "how high up must you be to be visible here" per "pixel", instead of "is the ground here visible", which I'd argue is more useful for modelling here. > except you didn't account for curvature of earth I didn't spell it out explicitly, but that's not the case if you do your projections right. (And you have to project, as SRTM data is always relative to the EGM96 geoid.)