| From: | Steve Crawford <scrawford(at)pinpointresearch(dot)com> |
|---|---|
| To: | Jeff Herrin <jeff(at)openhotel(dot)com> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: earthdistance compass bearing |
| Date: | 2013-06-18 18:37:10 |
| Message-ID: | 51C0A8D6.40803@pinpointresearch.com |
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| Lists: | pgsql-general |
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
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