The width of a degree of longitude varies by latitude; meridians of longitude converge to a single point at the poles. Latitude varies as well, although considerably less so, due to the rotation of the earth slightly squashing the poles, and bulging the Equator.
~ Eric. -----Original Message----- From: [EMAIL PROTECTED] on behalf of Gerald Nelson Sent: Thu 12/13/2007 3:06 PM To: 'Nikos Alexandris'; 'Michael Misun' Cc: grass-user@lists.osgeo.org Subject: RE: [GRASS-user] (kein Betreff) I'm curious about the statement that "Lat-Long is not good to do distance measurements" Someone else made a similar observation in a different conversation recently too. I'm not a geographer so I'm probably missing something but doesn't lat long just give you a point on the surface of the earth and if you have two of these don't you more or less automatically know the distance between them? Regards, Jerry -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Nikos Alexandris Sent: Thursday, December 13, 2007 10:55 AM To: Michael Misun Cc: grass-user@lists.osgeo.org Subject: Re: [GRASS-user] (kein Betreff) Lat-Long is not good to do distance measurements! Why don't you reproject your lines in a "metric" projection system and check the distances again. On Thu, 2007-12-13 at 14:03 +0100, Michael Misun wrote: > hello everybody! > i have a little problem: > i want to set vertices on lines in a specified space (e.g. 2 km) in a lat long coordinate system. > i tried it with "v.to.points -vi .... dmax=0.03" and it works. the problem is, that in the equatorial zone the space between the new added points is about 1,7 km but up to the polzones the spacing is rather smaller and about 600 m! > can anybody help me with this problem? a want to have an equal space for all vertices on my polylines > > michael -- Nikos Alexandris . Department of Remote Sensing & Landscape Information Systems Faculty of Forestry & Environmental Sciences, Albert-Ludwigs-University Freiburg . Tel. +49 (0) 761 203 3697 / Fax. +49 (0) 761 203 3701 / Skype: Nikos.Alexandris . Address: Tennenbacher str. 4, D-79106 Freiburg i. Br., Germany _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user