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it

Posts: 3
Registered: 10/15/08

ellipse on 3d earth
Posted: Oct 15, 2008 1:22 PM

Plain Text

I need equations for an ellipse that is over the earth to generate lat,long points in Google Earth.

I have the semiMajor,semiMinor, orientation and center lat/long points.

The equations I tried previously, I believe is for a flat surface and are not generating the correct points.

Here are the equations I'm using:

An ellipse rotated from an angle phi from the origin has as equation:

x= h + a cos( t) cos(phi) - b sin(t) sin(phi)
y = k + bsin(t)cose(phi)+ acos(t)sin(phi)

where (h,k) is the center, a and b the size of the major and minor
axis and t varies from -pi to pi.

Any help would be greatly appreciated.

Thanks