[OSM-dev] Area calculation without transformation

[Jochen Topf]

Hi!

I am bit late to the party... In osm2pgsql I am using boost::geometry
for these kinds of things. I found that to be much faster than GEOS/OGR.

https://github.com/osm2pgsql-dev/osm2pgsql/blob/master/src/geom-functions.cpp#L367-L379

Jochen

On Sun, Mar 24, 2024 at 03:44:24PM +0100, Florian Lohoff wrote:
> Date: Sun, 24 Mar 2024 15:44:24 +0100
> From: Florian Lohoff <f at zz.de>
> To: dev at openstreetmap.org
> Subject: [OSM-dev] Area calculation without transformation
> 
> 
> Hi,
> 
> I am looking into performance issued with QA code of mine and i am at one
> point i calculate the osm objects area.
> 
> I am using libosmium and gdal/OGR right now.
> 
> Now - to get a m² based area i am transforming into an planar EPSG
> which seems to be the bottleneck of processing.
> 
> I now had a quick look at postgis'es lwgeom code for ST_Area using
> a spheroid which my guess is much faster as i am on the very same spheroid
> all the time.
> 
> Does anyone know of a c++ implementation nicely plugging into
> libosmium/gdal/ogr processing just using the EPSG:4326?
> 
> Flo
> -- 
> Florian Lohoff                                                     f at zz.de
>   Any sufficiently advanced technology is indistinguishable from magic.



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-- 
Jochen Topf  jochen at remote.org  https://www.jochentopf.com/  +49-351-31778688