[postgis-devel] Much slower processing on GEOS 3.9.0 versus 3.8.0 for geodesic area calculation - Upgrade to PROJ 7.2.1 causes issue
pramsey at cleverelephant.ca
Wed Apr 28 16:07:24 PDT 2021
The ::geography cast requires that the SRID be verified as a geographic CS, which fires up some of the proj machinery. No transformation, but the somewhat expensive lookup of the CS parameters. So that's why proj infra is in the picture. That said, since the lookup times up pretty fast in my test program, I suspect that your hypothesis (bad packaging) might be the one?
> On Apr 28, 2021, at 3:13 PM, Mike Taves <mwtoews at gmail.com> wrote:
> The thing I'm confused about (geodesic area via ST_Area), is that it
> does not require any transformations. It only requires an ellipsoid
> definition. The computation is done via geodesic.c/.h from
> GeographicLib, which is the sole C file in PROJ.
> A possibility for the slowdown is that one of the components was
> compiled without optimization. E.g. with PROJ, doing "cmake .."
> without specifying "-DCMAKE_BUILD_TYPE=Release" would build an
> un-optimized PROJ.
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