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<p class=MsoNormal><span lang=EN-US>Hi all,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>We’re quite new to geographic fundamentals,
but it sounds like PROJ.4 is a pretty good base where to find proper ‘geographic
related’ libraries.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>We’re currently working on graphic
(2D/3D) tools for displaying accurate GPS information and our goal is to rely
on standard systems, avoiding to ‘reinvent the wheel’, feeling it
should be much of a benefit if we could share with the community.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>By now, we were able to properly use the ‘proj’
API in order to match different projection schemes into ‘Cartesian’
(3D space) coordinates, and also mix 2D representations.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>However, distance calculation seems to be
another issue.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>While we could find ways to implement a
reasonable calculation<o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-US>(for instance :<o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-US>gpsDist(PointF P1, PointF P2)<o:p></o:p></span></p>
<p class=MsoPlainText>{<o:p></o:p></p>
<p class=MsoNormal>return Acos( sin(P1.y)*sin(P2.y) +
cos(P1.y)*cos(P2.y)*cos(P1.x-P2.x) ) * earthRadius;<o:p></o:p></p>
<p class=MsoNormal><span lang=EN-US>}),<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>our approach considers it could be concentrated
on the same system, in order to provide consistency (at least sharing ‘earthRadius’
values).<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>In that manner, we failed to use ‘geod’
or affiliate as API.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>We have to say that we’re developing on
Windows platform (VS 2005), and we’re lacking sample/tutorial/help for
such a use.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Any help in that manner would be welcome.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>PS: Is there a proper (recommended) way to
increase ‘ellipsoid’ definitions (increasing or modifying ‘</span><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>pj_ellps’ table,
for instance changing “sphere”’s radius)?</span><span
lang=EN-US><o:p></o:p></span></p>
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