Backgrounds

The following commands may be executed within the GEOTEST context (activated with the SET/CONTEXT GEOTEST command).

CREATE/RAMP

produces square two-dimensional images of user-specified dimensions, with mean flux per pixel of 100 units, of user-specified slope of the plane, and with the plane itself sloping at a position angle. The latter can vary between 0 and 90 degrees.

For large slopes, the flux assigned to some pixels will be negative (-- this being dependent on the position angle).

CREATE/WAVE

produces an image with sinusoidal modulations along the horizontal axis. Again, the image is two-dimensional, of user-specified dimensions, and with user-specified amplitude and period. The sin function is always evaluated at the center of the pixel. The mean flux per period is 0 units.