| Re: How to display single orbits of satellite data in function graphics? [message #84156 is a reply to message #84121] |
Thu, 02 May 2013 10:01   |
Lajos Foldy
Messages: 176
Registered: December 2011
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Senior Member |
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Hi David,
On Thursday, May 2, 2013 4:53:44 PM UTC+2, David Fanning wrote:
> David Fanning writes:
>
>
>
>> P.S. Another way to speed this up would be to create your own user
>
>> symbol (circle) and specify PSYM=8 in the call. That way you would avoid
>
>> going into cgSymbol each time and *remaking* the circle there. That is
>
>> probably what is taking much of the time.
>
>
>
> This is interesting. Reducing the number of points in my circles from 72
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> to 36, made about 1 second of difference. Creating my own circle and
>
> passing PSYM=8 made about another second of difference. So, finally, I
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> tried to get as close to the machine as possible with this code:
>
>
>
> n = 793647L
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> lon = RANDOMU(seed,n)*360
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> lat = RANDOMU(seed,n)*180
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> cgLoadCT, 39
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> cgDisplay
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> circle = cgSymCat(3)
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> black = cgColor('black')
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> white = cgColor('white')
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> tic
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> PLOT, lon,lat, PSYM=circle, SYMSIZE=0.2, color=black, background=white
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> toc
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> END
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>
>
> This took 19 seconds, compared to my original 25 seconds in a fully
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> Coyote Graphics format. This seems to correspond pretty well to my rule
>
> of thumb that using Coyote Graphics routines adds about 20% rendering
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> time to the normal direct graphics time. But, I'm a little bit surprised
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> direct graphics is this slow here. Using a "dot" instead of a "circle"
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> can be done in about 8.5 seconds. So, circle rendering seems to be a
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> slower operation.
>
I tried this in Linux, it took 3.4 seconds through a remote X11 connection (3.2 seconds locally on a much slower machine). Maybe Windows is the limiting factor here :-)
regards,
Lajos
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