The full calling sequence of ISOCONT is:
ISOCONT, IMAGE_1, [ IMAGE_2 ], [ list_of_optional_keywords ]
where IMAGE_1 is to be displayed as a color image and IMAGE_2 (optional parameter) is to be plotted as contour level image. IMAGE_1 and IMAGE_2 can be a filename (if the image is stored on a disk in a FITS format file), or a variable name (if the image is stored in a CIA raster data structure in memory). Note that if an input image is in the form of a FITS file it should have the ``.fits'' extension in its filename. The list of all keywords is presented in Table 1. All keyword names are case insensitive. The keyword inputs can be strings, floating numbers or arrays, and logical (0/1) switches. For a logical switch, the calls ``/keyword'', ``/KEYWORD'', and ``keyword=1'' are equivalent.
A user-friendly widget which saves the user from typing all
ISOCONT keywords has also been developed. It is called by:
X_ISOCONT, IMAGE_1, [ IMAGE_2 ], [default='my_default_file.xdr']
This widget provides on-line help and an updated list of warning
messages. It can be very useful when one tries various sets of contour levels.
(See Fig. 1)
| Keyword | Default | Ref.1 | Function |
| BLACK2 | no | 6 | Select black as the color for contour levels and star sym bols. The default color is white. |
| C_COLOR | 255 | 6 | Specify the contour color. The default color is white. If C_COLOR=-1 then a spectrum of colors, uniformly spaced in the color-table, equal to the number of contours is selected and each contour has a different color. If C_COLOR is set to an array the standard rules of IDL color definition apply. |
| C_STYLE | 0 | 6 | Specify the line style used to draw each contour. The default style is a solid line. If C_STYLE=-1 then all negative contours are represented by a dashed line. If the input is an array the standard rules of IDL line style definition apply. |
| EPOCH | 2000 | 2, 3 | All coordinate labels are precessed to the specified EPOCH. The default epoch is J2000 for ISO raster data structures. |
| GRID | no | 2 | Overplot a coordinate grid. |
| LEVELS2 | none | 6 | Array of float values specifying the contour levels to display. |
| MAGNIFY | no | 5 | Magnifying factor (integer) of reference image (see REF). |
| MAX_VALUE2 | no | 6 | Maximum value of contours to display. |
| MIN_VALUE2 | no | 6 | Minimum value of contours to display. |
| MISSING | -1 | 2 | Value which is to be put in the undefined pixels of the display after a transformation of an image by the hastrom IDL routine. |
| NCD | 1.0 | 4 | Scaling factor which changes the character size (use NCD=0.5 to 0.66 for NCD X--terminals). |
| NLEVELS2 | 4 | 6 | Number of contour levels to display (maximum is 30). |
| NOCOLOR | no | 7 | Only IMAGE_2 is displayed (contour levels). |
| NOCOPYRIGHT | no | 3, 10 | No copyright label is displayed. |
| NOLEVEL2 | no | 7 | Only IMAGE_1 is displayed (color image). |
| NONORTH | no | 3, 10 | No north-east arrows are displayed. |
| NOSAMPLE | no | 1, 5 | Expansion (or contraction) of the reference (see REF) image is done using bilinear interpolation instead of the nearest neighbor method. |
| NTICS | 5 | 2 | Average number of tic-marks for the axis labels. |
| OFFSET2 | no | 8 | Array of 2 integers specifying the pixel shift of IMAGE_2. |
| OVERPLOT2 | no | 9 | ISOCONT output is displayed without erasing the previous graph on the window. |
| no | 10 | Generate a postscript file of the display window. named ``isocont.ps'' | |
| PUTINFO | no | 1, 6 | Add information (color table, contour levels, filenames and date) about the image at the right side of the window. |
| RADEC | 0 | 2 | Type of orientation of the images. The default is landscape, orientation, a label with the right ascension and declination of the image, and axes in units of arcsecs, arcmins, or degrees. Set /RADEC for astronomical orientation: North is up, East is to the left and the axes are the right ascension and declination. |
| RECT | no | 2 | Rectangular raster maps are fully displayed even with the /RADEC option. RECT is automatically set to 0 if /RADEC option is not used. |
| REF2 | 1 | 5, 8 | Number of image used as the astrometric reference. The reference is IMAGE_1 if REF=1 or IMAGE_2 if REF=2. |
| SCAN3 | no | 7 | Set /SCAN to display raster scan field of view. |
| SHIFT2 | no | 8 | Compute correlation between IMAGE_1 and IMAGE_2 in order to achieve better alignment. |
| SIZE | 650 | 4 | Average window size in screen pixels. |
| STAR | none | 3 | Plot a star symbol at given coordinates. Syntax is STAR=[RA,Dec] or STAR=[[RA_1,Dec_1], [RA_2,Dec_2], ...]. |
| TITLE | ISOCAM | 3 | Graph title. |
| WIN | 0 | 4 | Window number |