I wrote: > For smaller areas, the elliptical shape of the earth comes into play, > but you can approximate this by multiplying the latitude by the > semiminor axis of the ellipsoid you're using.
I've thought about the above a little, and it occurs to me that there would be less distortion if you used the semimajor axis for both X and Y coordinates, even on an ellipsoid. On a world map, it doesn't matter all that much, and on a map of a limited area near the Equator, the larger values are a lot closer to the actual distances from the Equator. You could probably work out a formula to optimize the Y factor based upon the area you were going to show. But it's probably not worth the effort. So, the Coordsys clause would be: Coordsys Earth Projection 1, 104 Affine units "m", 111319.49,0,0,0, 111319.49,0 HTH Spencer --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 13571
