When ISOCONT is used with two images as inputs, the astrometry of
IMAGE_1 (the color image) is taken by default as reference. This
means that IMAGE_2 is transformed in order to match the astrometry of
IMAGE_1 and to be superimposed on it as a contour plot. If one wishes
to have IMAGE_1 displayed as a color image using the astrometry of
IMAGE_2 as reference, one should set REF=2. Then IMAGE_1 will be
transformed in order to match the astrometry of IMAGE_2.
(See Fig. 11)
When two images from two different wavelength ranges are superimposed,
their respective resolutions can be very different. Using ISOCONT the
resolution of one image may be decreased seriously in order to match
that of the reference image. The MAGNIFY keyword allows the user to
rebin (taking nearest neighbor values by default) the reference image
with an expansion factor in order to virtually improve its resolution
and make the graph look nicer. If the bilinear interpolation is
prefered to the nearest neighbor method, the /NOSAMPLE keyword should
be to be used (see above section 3.1)
(See Fig.12)