Re: determining visible points

Hi Raymond,

Determining visibility of points in a terrain plot is a bit
tricky, and I don't think picking logic will help much.

You could use the Java3D Transform to transform the data
coordinates of your points into 3-D (x, y, z) screen
coordiantes, then for each point see if there is a point
at the same approximate x with smaller z (i.e., closer)
and larger y (i.e., higher and thus obscuring). The x test
has to be approximate since your points won't fall on neat
rows and columns once transformed into 3-D screen coords.

Note that a point might also be technically visible (from
underneath the terrain surface) if all the points in front
of it in z have larger y.

Good luck,
Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
hibbard@xxxxxxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738

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