Path_Filename Keyword

Used With Routines:   CONTOUR

Corresponding System Variable: None.

Specifies the name of a file to contain the contour positions.

If Path_Filename is present, CONTOUR does not draw the contours, but rather, opens the specified file and writes the positions, in normalized coordinates, into it. The file consists of a series of logical records containing binary data. Each record is preceded with a header structure defining the contour as follows:

{CONTOUR_HEADER, TYPE : 0B, HIGH : 0B, $
LEVEL : 0, NUM : 0L, VALUE : 0.0}

The fields are:

>TYPE—A byte which is zero if the contour is open, and one if it is closed.

>HIGH—A byte which is 1 if the contour is closed and above its surroundings, and is 0 if the contour is below. This field is meaningless if the contour is not closed.

>LEVEL—A short integer with value greater than or equal to zero. (It is an index into the Levels array.)

>NUM—The longword number of data points in the contour.

>VALUE—Contour value. This a single-precision floating-point value.

Following the header in each record are NUM pairs of single-precision floating (x,y) values, expressed in normalized coordinates.

The CONTOURFILL procedure can be used along with this file to fill the contours with specified colors or patterns. You can use CONTOUR with the Path_Filename keyword to get the path information and then use CONTOURFILL to fill the closed contours.

Use of this keyword implies use of the Follow keyword.