This routine (see below) seems to work well for a 'directions'
polyline with a high vertex count but seems to break with a simple
poly line with 2. Am I doing something wrong? Thanks
// Get the point X metres along the polyline, updating the step
description
private function getPointAtDistance(metres:Number):LatLng {
if (metres == 0) return polyline.getVertex(0);
if (metres < 0) return null;
var dist:Number=0;
var olddist:Number=0;
for (var i:uint=1; (i < polyline.getVertexCount() && dist <
metres); i++) {
olddist = dist;
dist +=
polyline.getVertex(i).distanceFrom(polyline.getVertex
(i-1));
}
if (dist < metres) {return null;}
var p1:LatLng= polyline.getVertex(i-2);
var p2:LatLng= polyline.getVertex(i-1);
var m:Number = (metres-olddist)/(dist-olddist);
// Use linear interpolation on the last bit
return new LatLng(p1.lat() + (p2.lat()-p1.lat())*m,
p1.lng() + (p2.lng()-p1.lng())*m);
}
On Nov 18, 5:55 pm, "pamela (Google Employee)" <[EMAIL PROTECTED]>
wrote:
> Hi bizpo-
>
> I believe that Mike William's EPoly extension for the JS API has a function
> that will calculate this for you - GetPointAtDistance. You can convert this
> function into AS3 for your own use. It may only work for non-geodesic
> polylines, however; I haven't tested that myself. Here's the page for the
> extension:http://econym.googlepages.com/epoly.htm
>
> - pamela
>
> On Wed, Nov 19, 2008 at 9:48 AM, bizpo <[EMAIL PROTECTED]> wrote:
>
> > How does one calculate the LatLng of points along a geodesic Polyline
> > connecting two points. I'd like to move a marker along this smooth
> > line that follows the curve of the earth. If that is not possible -
> > how could you calculate it along a straight line connecting two
> > points. Thank You.
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