Manifold Community Site: Distance between 2 pointshttp://95.79.92.2:8080/forum/t158883Manifold Community Site threadhttp://95.79.92.2:8080/forum/images/img-logo.pngManifold Community Site: Distance between 2 pointshttp://95.79.92.2:8080/forum/t158883RE: Distance between 2 pointshttp://95.79.92.2:8080/forum/t158883#158884<P>Given that I have 2 layers in lat/long, using GeomDistance I'm assuming the result is in degrees. How do I best convert this to feet/miles?</P><P>Thx.</P>wvayenshttp://95.79.92.2:8080/forum/t158883#158884http://95.79.92.2:8080/forum/t158883#158884Fri, 07 Jan 2022 23:18:09 GMTRE: Distance between 2 pointshttp://95.79.92.2:8080/forum/t158883#158885<P>Easiest thing to do is to display them in a projected map, then use the Tracker tool to measure their geographic distance as adjusted by the projection units. For SQL analysis, Check out Dimitri's discussion here: https://georeference.org/forum/t153908#153910</P><P>about the GeomLengthGeo() function.</P>oeaulonghttp://95.79.92.2:8080/forum/t158883#158885http://95.79.92.2:8080/forum/t158883#158885Sat, 08 Jan 2022 00:58:33 GMTRE: Distance between 2 pointshttp://95.79.92.2:8080/forum/t158883#158925<P><SPAN><B>https://georeference.org/forum/t153908#153910 </B></SPAN></P><P><SPAN>=> </SPAN><A HREF='t153908#153910'>New to MFD9...measurement problems (georeference.org)</A></P><P><SPAN><B>GeomLengthGeo() </B></SPAN></P><P><SPAN>=> </SPAN><A HREF='https://manifold.net/doc/mfd9/geom_sql_functions.htm'>Geom SQL Functions (manifold.net)</A></P><P><SPAN>GeomLengthGeo</SPAN>(<geom>, <major>, <eccentricity>, <tolerance>): <value></P><P>Given a geom that contains an area or a line object, and values for major axis, eccentricity, and tolerance, returns the geodetic length (computed on the surface of the ellipsoid) of that object, computed using Vincenty's formulae A tolerance of zero means automatic tolerance.</P><P>The length of an area object is the length of its boundary, that is, the perimeter of the area. The length reported for a branched object is the sum of the lengths of the branches.</P><P>The geom value must be an area or line in Latitude / Longitude, with X (longitude) and Y (latitude) expressed in degrees. The returned value is in units of the major axis.</P><P>Looking at the Custom tab of the <SPAN><A HREF='https://manifold.net/doc/mfd9/base_coordinate_system.htm'>Base Coordinate System</A></SPAN> dialog for the WGS84 base used for Latitude / Longitude projection, we can see the major axis is 6378137.01 and the eccentricity is 0.08181919084262149</P><P>Given a Mexico drawing of provinces as areas in Latitude / Longitude coordinate system, we can write:</P><P class='code'><span class=k>SELECT</span> GeomLengthGeo(<span class=i>[Geom]</span>, 6378137.01, 0.08181919084262149, 0) <span class=k>AS</span> <span class=i>[Geodetic Length]</span> <span class=k>FROM</span> <span class=i>[Mexico]</span>;</P>lionelhttp://95.79.92.2:8080/forum/t158883#158925http://95.79.92.2:8080/forum/t158883#158925Mon, 17 Jan 2022 00:41:10 GMTRE: Distance between 2 pointshttp://95.79.92.2:8080/forum/t158883#158938<P>Where is the Tracker tool I've seen mentioned a few times. (I'm familiar with it in M8, haven't seen it in M9.) There are a couple of references in the manual, but for the life of me, I can't locate it!</P>wvayenshttp://95.79.92.2:8080/forum/t158883#158938http://95.79.92.2:8080/forum/t158883#158938Mon, 17 Jan 2022 18:01:09 GMTRE: Distance between 2 pointshttp://95.79.92.2:8080/forum/t158883#158940<P>See <A HREF='https://manifold.net/doc/mfd9/measurements.htm'>this</A> topic in the manual. </P>Slootshttp://95.79.92.2:8080/forum/t158883#158940http://95.79.92.2:8080/forum/t158883#158940Mon, 17 Jan 2022 18:24:45 GMTRE: Distance between 2 pointshttp://95.79.92.2:8080/forum/t158883#158941<P>Thanks!</P>wvayenshttp://95.79.92.2:8080/forum/t158883#158941http://95.79.92.2:8080/forum/t158883#158941Mon, 17 Jan 2022 18:46:03 GMT