Follow Keyword

Used With Routines:   CONTOUR

Corresponding System Variable: None.

If present and nonzero, forces the CONTOUR procedure to use the line-following method instead of the cell-drawing method.

CONTOUR can draw contours using one of two different methods:

>The cell-drawing method, used by default, examines each array cell and draws all contours emanating from that cell before proceeding to the next cell. This method is efficient in terms of computer resources but does not allow contour labeling.

>The line-following method searches for each contour line and then follows the line until it reaches a boundary or closes. This method gives better looking results with dashed linestyles, and allows contour labeling, but requires more computer time. It is used if any of the following keywords is specified: C_Annotation, C_Charsize, C_Charthick, C_Labels, Follow, or Path_Filename.

Although these two methods both draw correct contour maps, differences in their algorithms can cause small differences in the resulting plot.