topic Re: Stereographic Projection in Discussions

Stereographic Projection

dhovis216 — Tue, 30 Jul 2024 13:49:56 GMT

This may be a long shot, but has anyone plotted stereographic projections in JMP? These are often used to represent the orientation of various crystal directions/planes, though it can be used for any projection relative to a sphere. I couldn't find anything searching.

Re: Stereographic Projection

Byron_JMP — Tue, 30 Jul 2024 15:53:52 GMT

kind of, probably, yes.

JMP uses Open GL to display rotatable 3D objects

This is a fun example from the scripting index.

Note: In the scripting index, search for "Open GL" to find objects and functions that might be handy

Names Default To Here( 1 );
gridsize = 10;
npoints = 32;
points = J( npoints, 3, 0 );
For( i = 0, i < npoints, i++,
	points[i, 1] = Random Uniform() - .5;
	points[i, 2] = Random Uniform() - .5;
	points[i, 3] = Random Uniform() - .5;
);
surface = Scene Display List();
surface << Enable( MAP2_VERTEX_3 );
surface << Enable( Auto_Normal );
surface << MapGrid2( gridsize, 0, 1, gridsize, 0, 1 );
surface << color( 0, 0, 1 );
surface << Map2(
	MAP2_VERTEX_3, 0, 1, 3, 4, 0, 1, 12, 4, points
);
surface << EvalMesh2(
	LINE, 0, gridsize, 0, gridsize
);
sb = Scene Box( 500, 400 );
sb << Ortho( -.75, .75, -.75, .75, -1, 1 );
sb << ArcBall( surface, 1 );
New Window( "Example", sb );

Re: Stereographic Projection

dhovis216 — Wed, 31 Jul 2024 13:54:22 GMT

That seems overkill for what I'd like. I'm sure it would work, but it would have it's own complications.

The stereographic projection here is a 2D plot that represents points on the surface of a sphere. It is probably easier to just convert angles to Cartesian coordinates and plot on a 2D plane. I guess I was just wondering if anyone had done that and I could reuse their work rather than starting anew.