As I am not on the postgis list I answer directly to Matthes, the solution is - maybe - simple. Define your own projection and buffer there. I would say it should be a Cylindric Projection (Oblique Mercator) which is touching/based on the great circle that runs between both cities. It would be similar to the swiss projection but with different origin and different azimuth: http://www.swisstopo.admin.ch/internet/swisstopo/en/home/topics/survey/sys/refsys/projections.html
ok.. maybe it isn't that simple and it will take a few days to realize that ;) stefan PS: thanks Martin for making aware PPS: I wonder if I did write a long time pseudo code in Mathcad to display the distortion of circles due to the UTM projection. But I may be wrong and it have been something else. Martin Davis wrote: > Check out this thread on the PostGIS list for more interesting > discussion on this topic. > > I wonder how Oracle would handle the USA-to-France buffer? Not well, > I'm betting... > > -------- Original Message -------- > Subject: Re: [postgis-users] Using a buffer with a LineString covering > the whole world > Date: Wed, 11 Feb 2009 08:58:16 -0800 > From: Paul Ramsey <[email protected]> > Reply-To: PostGIS Users Discussion <[email protected]> > To: PostGIS Users Discussion <[email protected]> > References: <[email protected]> > > > > I find running screaming into the hills helps. > > Sorry, that's the use case (really large/long things) where there just > is no proper solution except to start writing code that works on a > sphere. Most things just aren't that long/large. But a few are. I > would love it if someone/manyones would express their interest in > funding such a development. > > Want a hack? Cut your line into 1000 smaller lines. Buffer all those > individually in a planar space. The union them all back together > again, in lon/lat. > > P. > > On Wed, Feb 11, 2009 at 8:26 AM, Matthes Rieke > <[email protected]> wrote: >> Hi all, >> >> I am currently running into this problem: I have a LineString in lat/long >> coordinates (SRID 4326 - going from USA to france). I now want to create a >> buffer in meters from this. So the normal way to transfrom the coordinates >> to a planar CRS, buffering, then transforming back to 4326 does not work >> (the Line is covering many UTM zones). What would be a reasonable solution >> for this problem? >> >> Thanks and regards, >> Matthes >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > > > ------------------------------------------------------------------------------ Create and Deploy Rich Internet Apps outside the browser with Adobe(R)AIR(TM) software. With Adobe AIR, Ajax developers can use existing skills and code to build responsive, highly engaging applications that combine the power of local resources and data with the reach of the web. Download the Adobe AIR SDK and Ajax docs to start building applications today-http://p.sf.net/sfu/adobe-com _______________________________________________ Jump-pilot-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel
