Hi Kennedy,
Davidian wrote:
> I'm displaying OMEllipses on my map, and after talking with users of the
> software, I think that my assumptions about how this class works are
> incorrect.
>
> To construct an OMEllipse (with the constructor I'm using) you pass in the
> following:
>
> 1) A LatLonPoint that is the center point
> 2) A double that is the major axis span
> 3) A double that is the minor axis span
> 4) A Length object that is the unit being used (Meter in our case)
> 5) A double that is the rotation angle (or what we call "Orientation")
>
> In the following image you see an OMEllipse I created with an orientation of
> 45.0:
>
> http://www.nabble.com/file/p17515338/orientation_45.png
>
> This does not seem correct to me. In order for this image to be correct,
> that would mean that the "starting point" from which the ellipse was rotated
> (i.e., north) would be along the minor axis.
If your major axis had the larger value, it looks right to me.
> I've alway thought that the point from which the rotation occurs is along
> the major axis.
The rotation is performed around the center point.
> It looks like OpenMap's default way of drawing an OMEllipse (i.e., with a
> rotation angle of 0.0) is to place the major axis (longer) along the
> east/west plane, and the minor axis along the north/south plane.
Yes.
> If anyone could help I would greatly appreciate it. My software needs to
> the orientation plane to be parallel (not perpenducular) to the major axis.
What happens if you swap your axis values when you create the OMEllipse?
- Don
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Received on Wed May 28 2008 - 13:58:20 EDT
