<div dir="ltr">if you wanted accuracy, you'd have to convert them to a planar mapping (although I don't know which coord set would be appropriate to use?). kdtree just uses euclidean distances, which doesn't match the distance on a sphere.<br>
<br>you might be able to do something with UTM coords... except you will have to deal with the zones somehow.<br><br><div class="gmail_quote">2008/8/8 Gerald Gutierrez <span dir="ltr"><<a href="mailto:md1@mogeso.com">md1@mogeso.com</a>></span><br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div dir="ltr">Does anyone have experience with using kdtree's in a spherical mapping scenario? I need to batch geolocate a set of lats/longs to their closest cities (data from <a href="http://geonames.org" target="_blank">geonames.org</a>) and am having trouble working out how I would map the lats/longs into 2D coordinates that make sense for a kdtree. Not certain whether the spherical nature of the Earth would affect anything. Would I simply use lat/long as the kdtree coordinates, or do I need to convert them into a planar mapping first?<br>
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