| Re: Question on PLOTS command [message #2156] |
Tue, 07 June 1994 06:56 |
thompson
Messages: 584
Registered: August 1991
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Senior Member |
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dpal@glue.umd.edu (Debabrata Pal) writes:
> Hello everybody:
> I am trying to overlay the geometry of a computational domain on the
> contour plot. I am having no trouble in generating the contour plot. I
> am trying to generate the geometry of domain using PLOTS command. The
> geometry is very simple and can be generated by drawing a view
> horizontal nd vertical lines. But when i use PLOTS command to generate
> geometry, for example,
> PLOTS, [0, 0],[.9,.9], i get an error message like this
> % PLOTS: Data coordinate system not established.
> In other words, I am having trouble establishing the data coordinate system.
> Can anybody tell me how to establish the data coordinate system in this regard?
> thank you
> Deb
I'm not quite sure what you're trying to do, but PLOTS is basically the same as
OPLOT (and usually OPLOT is preferred in my opinion). Is it that you are
generating the contour plot and then trying to use PLOTS to draw a box within
it (which should work)? Or are you trying to use PLOTS first to establish the
coordinate system, followed by CONTOUR,/OVERPLOT? If the latter, then I would
suggest substituting PLOT for PLOTS.
However, if I understand what you're trying to do, it's much easier just to use
CONTOUR itself to establish the coordinate system. Just leave off the
/OVERPLOT qualifier. If necessary, you can use the XRANGE and YRANGE keywords
to limit the range, e.g.
CONTOUR, ARRAY, XPOINTS, YPOINTS, XRANGE=[0,0.9], YRANGE=[0,0.9]
(I figure that you must want to call CONTOUR with all three parameters with a
range like that).
Bill Thompson
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| Re: Question on PLOTS command [message #2158 is a reply to message #2156] |
Tue, 07 June 1994 06:17  |
stl
Messages: 70
Registered: February 1994
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Member |
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In article <2svmv4$6qf@mojo.eng.umd.edu> dpal@glue.umd.edu (Debabrata Pal) writes:
>
> Hello everybody:
>
> I am trying to overlay the geometry of a computational domain on the contour plot. I am having no trouble in generating the contour plot. I am trying to generate the geometry of domain using PLOTS command. The geometry is very simple and can be generated by drawing a view horizontal nd vertical lines. But when i use PLOTS command to generate geometry, for example,
>
> PLOTS, [0, 0],[.9,.9], i get an error message like this
>
> % PLOTS: Data coordinate system not established.
>
> In other words, I am having trouble establishing the data coordinate system.
> Can anybody tell me how to establish the data coordinate system in this regard?
Hi,
Okay, IDL uses 3 coordinates systems:
Normal all data is between 0-1
Device for display, this is pixel coord
Data coordinates established with data range of a plot (or
controur, etc..)
Different routines have different defaults of what coordinate type to
accept. I believe your above command will work as follows: (assuming
you do indeed want to use normal coordinates)
PLOTS, [0, 0],[.9,.9],/Normal
This plots from point (0,0) to (.9,.9).
Remember, the first array are the x coordinates, and the second array
are the y coordinates.
-stephen
hope this helps a little
--
Stephen C Strebel / SKI TO DIE
strebel@sma.ch / and
Swiss Meteorological Institute, Zuerich / LIVE TO TELL ABOUT IT
01 256 93 85 / (and pray for snow)
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