From: edwin@dutind2.twi.tudelft.nl (Edwin Vollebregt)
Subject: plots with different options in one picture?
Organization: Delft University of Technology, Dept. of Electrical Engineering
Date: Tue, 17 Nov 1992 10:16:42 GMT

Dear Netters,

    Currently I'm working on a finite difference program for calculating
the flow of water in some region. I'm trying to provide graphical output
with GNUplot. I'm having a lot of difficulties, and that's why I'm turning
to you all out there.
 
Here are some of the things that I want GNUplot to do. I can't find out
how they are possible, if they are.
    Questions: 
       - do you know how I can make the desired plots?
       - if GNUplot is not capable of something, do you think that it
         SHOULD BE, are you experiencing the same problems?

 Consider some 2D region, e.g. a lake. Define a grid, and the depth
 at each grid-point d(x,y). The grid g(x,y) looks like:
         0  0  1  1  0  
         1  1  1  1  1     
         0  1  1  0  0
 
 1) Can I plot the 3D surface d(x,y) and the contour-lines of g(x,y) in
    one picture?  (especially the contour g(x,y) = 0.5 is interesting,
    because it is the outline of the lake)

 2) Can I plot the 3D surface d(x,y) in non-parametric mode (hidden line)
    and the outline of the lake in parametric mode (a number of coordinate
    points) ?

 3) Can I plot the 3D surface d(x,y) with data-style lines and the grid-
    points with data-style points ?

 These three questions can be summarized by:
    Is it possible to show plots with different options ((no) contour,
    data-style, 2D/3D, (non)parametric, ...) in one picture ?

 Now consider the currents in the lake. In each grid-point we know the
 U velocity in x-direction and V velocity in y-direction.
      e.g.     ^       --  -  \
             y |     / -   \  |
                     \ --  -  /
                -> x

 4) Can I plot the vector-field (U(x,y), V(x,y)) in a 2D picture in some
    other way than using  set arrow from x, y to x+U, y+V  all the time ?

 5) Can I draw the outline of the lake in there too ?

Maybe I haven't looked at GNUplot good enough, or am I asking too much.
But when you have the same problems, it might be worth while to extend
GNUplot with some new features.

Now, after reading all this stuff, it can't be too much when asking for 
your reply.
                         Hope to hear from you soon,
                                                      Edwin
 _________________________________________________________________________ 
|                            |                                 |          |
| Ir. E.A.H. Vollebregt      |  Section of Applied Mathematics |    ,==.  |
|                            |  Delft University of Technology |   /@  |  |
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       Why bother about graphics programs, when you can make such nice
       pictures with the ASCII set only...

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