Problem with adjusting zrange for legend in contour plot.

[Adamszk]

I am trying to replicate matlab code with fortran. Matlab is using contourf feature which I can translate with ogpf library using contour funtion with fortran. Numerical data for (x,y,z) used for plot are the same, however the plots looks different. I realized that when color box are displayed, the range for z data or range of color in legend is different. For example, all z values are close to 1, matlab z range is from 0 to 2, while Fortran z range in color box is 0.99 to 1.01 So the obvious step is to change the color/z data range in Fortran. However, I do not see options listed/available to do that.
I tried the following,

call gp%axis([-1.0,+1.0,-2.0,+2.0,0,+2.0]) ! Sets all axis at same time

It does not work (for z data). I also tried the following,

call gp%xlim([-1.0,+1.0]) ! Sets only the xrange call gp%ylim([-2.0,+3.0]) ! Sets only the yrange call gp%zlim([0,+2.0]) ! Sets only the zrange

All these calls do not work.

Any suggestions?

Below is the test code for GNU Octave/Matlab

` figure 1;
%
% ------------------------------------------------------------------
% Use this example to test my problem with contourf plotting of data
% ------------------------------------------------------------------
%
%
%
%
% Create a vector of x values
x = linspace(-2pi,2pi,2);
% Create a vector of y values
y = linspace(0,4*pi,2);
% Make matrices with all combinations of x and y values for plotting
[X,Y] = meshgrid(x,y);
Z = sin(X)+cos(Y);

X
Y
Z

colormap ("default");
contourf(X,Y,Z)
title ({"Example 4: contourf() Z = sin(x) + cos(y) "});
colorbar ();
colorbar on;
`
This is a code in Fortran,

`subroutine problem111()
type(gpf):: gp

    real(wp), allocatable:: x(:,:)
    real(wp), allocatable:: y(:,:)
    real(wp), allocatable:: z(:,:)
    integer:: m
    integer:: n
    real(wp), parameter :: pi=4.0_wp*atan(1.0_wp)
    real(wp), parameter :: ppi=8.0_wp*atan(1.0_wp)
    real(wp), parameter :: ypi=16.0_wp*atan(1.0_wp)
    real(wp), parameter :: zpi=2.0_wp*atan(1.0_wp)
    
    ! create the xyz data
    call meshgrid(x, y, linspace(-ppi,ppi, 2), linspace(0.0_wp,ypi, 2)  )

    m=size(x,1)
    n=size(x,2)
    allocate( z(m,n) )

    z = sin(x)+cos(y)

    call gp%options('unset key')
    call gp%options('unset surface')
    call gp%options('set colorbox')
    call gp%axis([real(wp):: -ppi, ppi, 0, ypi, 0, zpi])
    call gp%title('my contour problem 111 test plot 2')
    call gp%contour(x,y,z, lspec='t "Matlab Jet"', palette='jet')

   ! plot the contour
   ! call gp%options('unset border; unset tics')
   ! call gp%title('My contour problem 111 test plot 1')
   ! call gp%surf(x,y,z, palette='accent')

print*, " rank of x = ", rank(x)
print*, " rank of y = ", rank(y)
print*, " rank of z = ", rank(z)

print*, " x = ", x
print*, " y = ", y
print*, " z = ", z
end subroutine problem111`

[kookma]

You may know ogp actually calles gnuplot! So, would you please give a try directly in gnuplot!
If it works, then we can revise the code here to address this issue.

[Adamszk]

The source of my problem is the option that is available in matlab contour which is vn in :

``contourf (x, y, z, vn)"

"The optional input vn is either a scalar denoting the number of contour lines to compute or a vector containing the Z values where lines will be computed. When vn is a vector the number of contour lines is numel (vn). However, to compute a single contour line at a given value use vn = [val, val]. If vn is omitted it defaults to 10."

I do not see that option vn available in ogpf function.
Currently I am looking in GNU Plot if that option is there.

[kookma]

Yes, please first check the http://gnuplot.info/
If you have the option there, then you can pass it using ogpf to gnuplot.

Would you please check these pages:

• https://gnuplot.sourceforge.net/demo_6.0/contours.html
• http://gnuplot.info/docs_6.0/loc10726.html

A good example is here: https://stackoverflow.com/a/57090231/439976