dom — vfplot domain file format


The dom file format is used by the vfplot(1) program for representing the boundary of a vector field.

The format is plain ASCII and consists of a number of paths concatenated. A path is a header line, a hash (#) and optional ignored text, followed by at least one point line. A point line consists of a pair of floating point numbers separated by whitespace.

All path are closed but the last point of a path need not (should not) be the same as the first, the final segment is implicit.

A path should not intersect itself, nor any other path. A path may be entirely contained within another path, for example for a domain with a hole. In this case the contained path should occur in the file after the containing path (this restriction may be removed at a later date). The outermost path is interpreted as the boundary of a finite domain (a domain must be finite in extent), a path inside that is the boundary of a hole, a boundary inside that is a boundary of an island domain in the hole and so on. The orientation of the points (clockwise or anticlockwise) is irrelevant, in contrast to many other vector formats.


The following file describes a square domain with a square hole in it.

# square
-40 -40
-40  40
 40  40
 40 -40
# hole
-30 -30
-30  30
 30  30
 30 -30


J.J. Green ()