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    <p>PostgreSQL does not factor in altitude when calculating distances. It is all done in a planar surface.</p> <p>Most of database spatial packages will not take this into account, altought, if your point is 3d, i.e., has a Z coordinate that might happend.</p> <p>I don´t have PostgreSQL in this machine, but try this.</p> <p>SELECT ST_DISTANCE(ST_POINT(0,0,10),ST_POINT(0,0,0));</p> <p>It´s fairly easy to know if it is taking into account your Z value, since the return should be > 0; If that turns out to be true, just create Z aware features, and you will be successfull.</p> <p>What SQL SERVER 2008, for example, takes into account when calculating distances, is the position of a Geography feature in a sphere. Geometry features in SQL SERVER will always use planar calculations.</p> <p><strong>EDIT: checked this in PostGIS manual</strong></p> <p>For Z aware points you must use the ST_MakePoint function. It takes up to 4 arguments (X Y Z and M). St_POINT only takes two (X Y)</p> <p><a href="http://postgis.refractions.net/documentation/manual-1.4/ST_Distance.html" rel="nofollow noreferrer">http://postgis.refractions.net/documentation/manual-1.4/ST_Distance.html</a> ST_DISTANCE = 2D calculations</p> <p>ST_DISTANCE_SPHERE documentation (takes in account a fixed sphere for calculations - aka not planar) <a href="http://postgis.refractions.net/documentation/manual-1.4/ST_Distance_Sphere.html" rel="nofollow noreferrer">http://postgis.refractions.net/documentation/manual-1.4/ST_Distance_Sphere.html</a></p> <p>ST_DISTANCE_SPHEROID documentation (takes into account a choosen spheroid for your calculations) <a href="http://postgis.refractions.net/documentation/manual-1.4/ST_Distance_Spheroid.html" rel="nofollow noreferrer">http://postgis.refractions.net/documentation/manual-1.4/ST_Distance_Spheroid.html</a></p> <p>ST_POINT documentation <a href="http://postgis.refractions.net/documentation/manual-1.4/ST_Point.html" rel="nofollow noreferrer">http://postgis.refractions.net/documentation/manual-1.4/ST_Point.html</a></p>
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    1. POMaps: Does calculating distance between 2 points factor in altitude?
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    1. USGeorge Silva
    1. USGeorge Silva
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    1. CO@George, what's unclear to me reading the links you provided is if it accounts for altitude changes in between the 2 end points. For example, let's say that both end points are at the ocean altitude (0) but a mountain exists in between the two points. The altitude change in climbing that mountain to set from point A to point B should be factored in.
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