The code for azimuth on a sphere isn't so gnarly you couldn't whip it up in plpgsql,
http://trac.osgeo.org/postgis/browser/trunk/liblwgeom/lwgeodetic.c#L924 P. -- Paul Ramsey http://cleverelephant.ca http://postgis.net On Tuesday, June 18, 2013 at 11:16 AM, Jeff Herrin wrote: > I don't need it to be too accurate. We're pushing hotel info into the GDS > (sabre, expedia, orbitz, etc). They require airport info relative to the > hotel. Example: DFW is 25 miles NW of the property. I thought about just > faking it...comparing the hotel's lat/long from the airports. I can probably > get N,S,E,W reliably enough, but i'm not sure at what point N becomes NW, > etc. That just seems like a really crude bad way to do it, but the > alternatives seem unnecessarily complex. I found some examples that use > bearing but they all take headings in degrees (which im not seeing in > earthdistance). I guess I'm going to have to either setup postGIS or brush up > on my trig. > > thanks, > altimage > > From: "Steve Crawford" <scrawf...@pinpointresearch.com > (mailto:scrawf...@pinpointresearch.com)> > To: "Jeff Herrin" <j...@openhotel.com (mailto:j...@openhotel.com)> > Cc: pgsql-general@postgresql.org (mailto:pgsql-general@postgresql.org) > Sent: Tuesday, June 18, 2013 11:37:10 AM > Subject: Re: [GENERAL] earthdistance compass bearing > > On 06/18/2013 10:42 AM, Jeff Herrin wrote: > > I'm trying to get a compass bearing (N,S,NW,etc) using earthdistance. I can > > successfully get the distance between 2 points using either the point or > > cube method, but I've been struggling with getting the bearing. Any tips? > > > PostGIS has some functions that may be of use but might be overkill depending > on your use but I don't see anything in earthdistance. > > What are you trying to solve? > > It's one thing if you are looking for a one-degree-accurate > magnetic-variation-compensated great-circle heading for a 6,000km flight > using WGS84 projection (initial-heading, of course, as it will vary over the > course of your travel). > > If you just want to be accurate to eight compass-points over a few > city-blocks then simple trig is probably more than sufficient. > > Cheers, > Steve -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
