Hi John,
You can choose the number of tick marks that cross an image via a
right click in any image window color bar (to the right of the image
in the window), and setting "Tick Div" to be the number of tick marks
across each edge of the image.
However, if you set AFNI_IMAGE_TICK_DIV_IN_MM to YES, then "Tick Div"
actually means that distance in mm.
So on an image that is 240 mm across, setting Tick Div to 10 would
normally give you 10 tick marks (intervals, actually) of 24 mm each.
With that env var set, it would give you 24 tick marks of 10 mm each.
"Tick Size" determines the length of each tick mark.
Keep in mind that the images are only a cross section. Distances may
be shorter in 3-D space. Of course they are drastically different
along the cortical surface.
See README.environment for similar details.
- rick
