PGPLOT Module: PGCONL -- label contour map of a 2D data array
SUBROUTINE PGCONL (A, IDIM, JDIM, I1, I2, J1, J2, C, TR,
1 LABEL, INTVAL, MININT)
INTEGER IDIM, JDIM, I1, J1, I2, J2, INTVAL, MININT
REAL A(IDIM,JDIM), C, TR(6)
CHARACTER*(*) LABEL
Label a contour map drawn with routine PGCONT. Routine PGCONT should
be called first to draw the contour lines, then this routine should be
called to add the labels. Labels are written at intervals along the
contour lines, centered on the contour lines with lettering aligned
in the up-hill direction. Labels are opaque, so a part of the under-
lying contour line is obscured by the label. Labels use the current
attributes (character height, line width, color index, character
font).
The first 9 arguments are the same as those supplied to PGCONT, and
should normally be identical to those used with PGCONT. Note that
only one contour level can be specified; tolabel more contours, call
PGCONL for each level.
The Label is supplied as a character string in argument LABEL.
The spacing of labels along the contour is specified by parameters
INTVAL and MININT. The routine follows the contour through the
array, counting the number of cells that the contour crosses. The
first label will be written in the MININT'th cell, and additional
labels will be written every INTVAL cells thereafter. A contour
that crosses less than MININT cells will not be labelled. Some
experimentation may be needed to get satisfactory results; a good
place to start is INTVAL=20, MININT=10.
Arguments
A (input) : data array.
IDIM (input) : first dimension of A.
JDIM (input) : second dimension of A.
I1, I2 (input) : range of first index to be contoured (inclusive).
J1, J2 (input) : range of second index to be contoured (inclusive).
C (input) : the level of the contour to be labelled (one of the
values given to PGCONT).
TR (input) : array defining a transformation between the I,J
grid of the array and the world coordinates.
The world coordinates of the array point A(I,J)
are given by:
X = TR(1) + TR(2)*I + TR(3)*J
Y = TR(4) + TR(5)*I + TR(6)*J
Usually TR(3) and TR(5) are zero - unless the
coordinate transformation involves a rotation or
shear.
LABEL (input) : character strings to be used to label the specified
contour. Leading and trailing blank spaces are
ignored.
INTVAL (input) : spacing along the contour between labels, in
grid cells.
MININT (input) : contours that cross less than MININT cells
will not be labelled.