| Over-plotting problem... [message #9309] |
Wed, 25 June 1997 00:00  |
Gregory Grason
Messages: 1
Registered: June 1997
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Junior Member |
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Specifically what is a user symbol and why would I need one to
over-plot? I've never encountered this error before:
% OPLOT: No user symbol defined.
-Greg Grason
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| Re: Over-plotting problem... [message #9423 is a reply to message #9309] |
Fri, 27 June 1997 00:00  |
Jim O'connor
Messages: 7
Registered: March 1996
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Junior Member |
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Gregory Grason <grason@jhuapl.edu> writes:
> Specifically what is a user symbol and why would I need one to
> over-plot? I've never encountered this error before:
>
> % OPLOT: No user symbol defined.
>
A user symbol (basically a user-supplied polygon) is useful if you
want to use a period as a plotting symbol, but want to make the period
larger than a vanishingly small dot. You might figure SYMSIZE would
work with PSYM=3, the built-in period symbol, but it doesn't. Thus:
Wave> x = findgen(100)/99.*2*!Pi*3
Wave> plot,x,sin(x),psym=3,symsize=4
does not make large dots. However, if you define a user symbol like
this:
Wave> r0=1.0 & inc=16
Wave> a=FINDGEN(inc) * (!PI * 2 /inc)
Wave> a = [a,a(0)] ;close the symbol
Wave> USERSYM, r0*cos(a),r0*sin(a),/fill ;creates a filled symbol
you can now get big dots with this:
Wave> plot,x,sin(x),psym=8,symsize=4
--
Jim
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