Colin Wetherbee wrote:
I'm looking for a function to approximate a partial great circle (eg.
the route taken when flying from London to Tokyo) as a LINESTRING or
something similar.
Does such a beast exist? If not, do you have any pointers on how to go
about implementing that kind of a function in, say, PL/pgSQL?
To follow up, Dane and I had some unsuccessful ideas last night about this.
We tried casting the points to a spherical projection, creating the
line, and then casting back to the native projection, SRID 4326. We
also tried other combinations of the same tactic. The spherical
projections we tried had SRIDs 53027, 4047, and 2163.
I'm still looking for a method of doing this.
My application uses OpenLayers to display MapServer-generated data, and
MapServer uses PostgreSQL/PostGIS as a back-end. The routes I'd like to
see on the map connect airports, and right now, they just look like a
piece of string pulled across a flat map. I'd like them to look more
like a piece of string pulled across a globe.
The ideal case would be a projection that could give me a perfectly
curved line, which I could then project onto the flat map. However, I
would settle for some sort of function that gives me a LINESTRING that
approximates that curved route. London to New York could have 20
segments or something like that.
Thanks.
Colin
_______________________________________________
postgis-users mailing list
postgis-users@postgis.refractions.net
http://postgis.refractions.net/mailman/listinfo/postgis-users
