CNTLN plots a contour plot of a randomly scattered set of points in three dimensions. The input consists of a list of triplets of a surface value. The triplets are triangulated using TRIANGC and contours determined by linearily interpolating the edges of the triangles. The contour values may be uniformly spaced between the starting and end values or from a list. Other than color, the sequence of plotting (min to max), and line typing of various contour lines, no contour line identification scheme is provided. Caution should be exercised when interpreting plot since the distribution of input points may affect the placement of the contour lines.
CALL CNTLN(x,y,z,n,xl,yl,iflag,nc,c,ia,xt,nxt,tx,sx,fx,
yt,nyt,ty,sy,fy,t,nt,xm,xx,ym,yx<<,ic>,l>)
x,y,z (R): array of point triplets (x,y,z)
n (I): number of points
xl (R): x axis length in inches
yl (R): y axis length in inches
iflag (I): option flag
< 0 : do not close LONGLIB after plotting
= 0 : close LONGLIB--no plot produced
> 0 : close LONGLIB after plotting
(magnitude) >10000: do not initialize LONGLIB before plotting
(1's digit) = 1 : do not use color or line type arrays
= 2 : use color but not line type array
= 3 : do not use color but use line type array
= 4 : use both color and line type arrays
(10's digit) = 0 : just x,y labeled axes
= 1 : axes and axis line/ticks on top and sides
(100's digit) = 0 : Ask which screen device to use
<> 0 : Screen Device Number (see FRAME)
nc (I): number of contour levels
< 0 : c(1) is the minimum contour level and c(2) is
the contour step size, abs(nc) levels plotted
> 0 : c contains contours levels, c dimensioned c(nc)
c (R): list of contour levels
ia (I): axis option flag
< 0 : do not plot axes
> 0 : plot axes
(1's digit) = 1 : plot y axis using max/min of y array
= 2 : plot y axis using max/min of y array
smoothed by SCALE
= 3 : plot y axis using input max/min
= 4 : plot y axis using input max/min
smoothed by SCALE
(10's digit) = 1 : plot x axis using max/min of x array
= 2 : plot x axis using max/min of x array
smoothed by SCALE
= 3 : plot x axis using input max/min
= 4 : plot x axis using input max/min
smoothed by SCALE
(100's digit) = 0 : normal contouring
= 1 : show triangulation used without contours
xt (C): x axis title string
nxt (I): number of characters in title
< 0 : axis ticks on top of x axis
= 0 : no axis
> 0 : axis ticks on bottom of x axis (normal)
tx (R): number and pattern of axis ticks (see AXIS3)
sx (R): size of axis labeling (see AXIS3)
< 0 auto exponent scaling (x10 to power) disabled
> 0 auto exponent scaling (x10 to power) enabled
fx (R): format of axis number labeling (see AXIS3)
yt (C): y axis title string
nyt (I): number of characters in title
< 0 : axis ticks on top of x axis
= 0 : no axis
> 0 : axis ticks on bottom of x axis (normal)
ty (R): number and pattern of axis ticks (see AXIS3)
sy (R): size of axis labeling (see AXIS3)
< 0 auto exponent scaling (x10 to power) disabled
> 0 auto exponent scaling (x10 to power) enabled
fy (R): format of axis number labeling (see AXIS3)
t (C): plot title string
nt (I): number of characters in t (limited to 99 characters)
< 0 : use color array
= 0 : no title
> 0 : do not use color array
if |nt|/100 > 0 : use line type list
xm (R): minimum value of x axis
xx (R): maximum value of x axis
ym (R): minimum value of y axis
yx (R): maximum value of y axis
ic (I): color list (optionally used)
ic(1) : color for axis lines
ic(2) : color for axis numbers
ic(3) : color for axis titles
ic(4) : color for axis exponents
ic(5) : color contour (1)
ic(6) : color contour (2), etc.
... ...
l (I): line type list for contours (optionally used)
common /ccntrplt/xmr,dxr,ymr,dyr
xmr (R): returned value of xmin
dxr (R): returned value of scale factor (xmax-xmin)/xlen
ymr (R): returned value of ymin
dyr (R): returned value of scale factor (ymax-ymin)/ylen