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## Re: How do you change to an ordinate on gsplot?

 From: Henry F. Mollet Subject: Re: How do you change to an ordinate on gsplot? Date: Sun, 24 Apr 2005 10:57:01 -0700 User-agent: Microsoft-Entourage/10.1.1.2418

```Not quite sure if I'm answering your question but gsplot z will use a
counter for x and y starting at 0 (has a name but I cannot think of it right
now)
*whereas* mesh (x,y,z') will use x and y as given. Note that one has to use
z' to get the same plot. [That is a right-handed coordinate system according
to z = cross-product of x and y (turning x-axis (vector) counter-clockwise
towards y-axis (vector) produces z-axis (vector) pointing up].

Octave input follows and 2 graphs are attached for demonstration.
Henry

octave:13> x=[1:1:5]
x =
1  2  3  4  5
octave:14> y =[2:2:10]
y =
2   4   6   8  10
octave:15> [xx,yy]=meshgrid(x,y)
xx =
1  2  3  4  5
1  2  3  4  5
1  2  3  4  5
1  2  3  4  5
1  2  3  4  5
yy =
2   2   2   2   2
4   4   4   4   4
6   6   6   6   6
8   8   8   8   8
10  10  10  10  10
octave:16> z = xx.^2+yy.^2
z =
5    8   13   20   29
17   20   25   32   41
37   40   45   52   61
65   68   73   80   89
101  104  109  116  125

octave:18> gset term aqua 1
octave:19> gsplot z  % saved as Fig1_gsplot
octave:21> gset term aqua 2
octave:22> mesh (x,y,z') % savedd as Fig2_mesh

on 4/24/05 6:54 AM, Robert A. Macy at address@hidden wrote:

> How do you change to an ordinate "scale" in gsplot?
> I'm not mathematical, so I may be using the wrong terms,
> but what I mean is:
> Given a two dimensional array of real values,
> the line...
>
>>> gsplot values;
>
> ...something automatically makes a great 2d mesh plot
> with x = rowsofvalues and y = columnsofvalues
> and z = values
>
> I want y to be transformed to a different "scale".
>
> I have specific values for the scale.  The values are not
> uniform. so the mesh display has "sawtooth" like artifacts.
> How do I change the y to be a function of indices?
>
> Stated another way.
>
> How do I 2d mesh plot an array with x = index of rows
> and y = monotonic function ( index of columns ) ??
>
>                 - Robert -
>
>
>
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```

Fig1_gsplot.pdf
Description: Binary data

Fig2_mesh.pdf
Description: Binary data