Help for ELLIPSE

PURPOSE:
To create images of oblate spheroids for testing map projections.

EXECUTION:
To create an ellipse with a polar to equatorial radius ratio of 1/2.
ellipse out=a.img nl=500 ns=1000

To test map3 and overlay.
ellipse out=z.img nl=502 ns=1002
map3 inp=z.img out=e.img 'noproj 'nosedr    nl=502 ns=1002 scale=1. 'perspect line=251 samp=501    north=0. latitude=45. longitud=0
overlay inp=e.img out=f.img dla1=10 dlo1=30
xvd f.img

METHOD:
Ellipse draws an ellipse viewed from the equatorial plane from infinity.
North is up. It is centered in the output image and fills the entire image.
The background is set to dn=1 and the ellipse is drawn as dn=255.
Planetocentric latitudes are drawn every 10 degrees.
An mp perspective projection label is placed on the image where the
range to the ellipse is 1000 radii.
The ellipse oblateness is the ratio of nl/ns.

HISTORY:
2-1-97  J Lorre. 
COGNIZANT PROGRAMMER:  Jean Lorre

PARAMETERS: