This program superimposes a user-defined grid on an input image.

Two types of grids are available:

1. A graticule based on latitude and longitude coordinates where (MODE=GROUND).
2. A simple rectangular grid based on line and sample coordinates where (MODE=IMAGE).

Defaults:

• MODE = GROUND
• BASELAT = 0.0
• BASELON = 0.0
• LATINC = 10
• LONINC = 10

Use the GROUND mode for images that have SPICE or map projection information. Use the IMAGE mode for images that do not have SPICE or map projection information, or to draw grid lines based on sample and line information.

The grid pattern will intersect a specific origin of either (latitude,longitude) or (sample,line) position. Grid lines are drawn at intervals from the origin based on the increment values defined by the user. The graticule produced may not match the image coordinates exactly, so the result will have outer grid cells that might have different heights and widths than the interior grid cells. In addition, if the LATINC and LONINC are too large compared with your image map scale, the grid lines may miss your image. If the increments are too small, the grid lines may be overly dense.

This application will draw grids on either ISIS level0, level1 (with successful spiceinit), and level2 cubes, or mosaics. The mapping information in the labels will be used to draw grid lines on mosaics and Level2 images. If the latitude and longitude information cannot be calculated or extracted using the image label contents, then use the IMAGE mode.

For Cubes with an associated band-dependent camera model (latitude, longitude coordinates do not correspond to the same sample, line coordinates in each band,) the grid is recalculated for each band.

Example Parameter Settings for Grids:
Example 1: Superimpose a basic latitude/longitude graticule with grid lines drawn every 10 degrees based on zero:
MODE=GROUND BASELAT=0 BASELON=0 LATINC=10 LONINC=10

Example 2: Superimpose a graticule on an input image that intersects at line 23 and sample 17, with vertical lines drawn every 30 pixels and horizontal lines every 40 pixels:
MODE=IMAGE BASELINE=23 BASESAMPLE=17 SINC=30 LINC=40
Note: MODE=GROUND cannot be used when sample and line coordinates are used.

Example 3: Superimpose a latitude/longitude graticule with a grid intersection at -5.0 degree latitude and 140.0 degree longitude, with latitude lines drawn every 2.5 degrees and longitude lines drawn every 3 degrees:
MODE=GROUND BASELAT=-5.0 BASELON=140 LATINC=2.5 LONINC=3

Example 4: Superimpose a latitude/longitude graticule within a subarea of an image (full latitude and longitude extent), with a grid line drawn every 2.5 degrees between latitudes -8 and -1 degrees and only between longitudes 140 and 145 degrees:
MODE=GROUND BASELAT=0 BASELON=0 LATINC=2.5 LONINC=2.5 MINLAT=-8 MAXLAT=-1 MINLON=140 MAXLON=145 Bound=yes

For complex grids, the grid application can be run multiple times with different parameter settings for each successive run that builds onto the previous output file. The TICKS option can be used to draw short ticks instead of grid lines. The OUTLINE option will draw grid lines along the outside edges of the first and last samples and lines of the input file. The BOUNDARY option will either draw grid lines around the outside edges of the input file or around the bounding box specified by the user with MINLAT, MAXLAT, MINLON, and MAXLON parameters.

In this example, the latitude and longitude grid lines are drawn every 10 degrees starting at 0.0 degree latitude and longitude.

In this example, the grid lines are drawn based on the line and sample coordinates entered by the user in IMAGE mode.

In this example, the grid lines are drawn based on a set of user-defined values for the different latitude and longitude parameters. The graticule is drawn only within the minimum and maximum latitude and longitude extents entered by the user.