MGH_EXAMPLE_SCATTER Name
MGH_EXAMPLE_SCATTER Purpose
3D scatter plot example.
For a discussion of the different representations possible for a
3D scatter plot in object graphics see:
http://www.sljus.lu.se/stm/IDL/misc/scatter_surface.txt
I used this procedure to test relative times for creating & drawing
different symbol types. In each case I used STYLE=0 (single polyline
with a single symbol object) and N_POINTS=10000. Times for execution
of the procedure (IDL 5.3 on Pentium II 400 MHz) were compared for
different symbol types:
IDLgrSymbol with DATA=6 (square): 0.78 s
IDLgrSymbol with DATA set to a 4-vertex polyline 1.52 s
IDLgrSymbol with DATA set to a 16-vertex polyline 1.68 s
IDLgrSymbol with DATA set to a model containing a
4-vertex polyline 1.91 s
IDLgrSymbol with DATA set to a model containing a
16-vertex polyline 2.08 s
IDLgrSymbol with DATA set to a 4-vertex polygon 1.72 s
Conclusions:
- The simplest user-defined symbols (DATA = a polyline) are about
a factor of 2 slower than the built-in symbols.
- Drawing time increases with the number of vertices in the symbol,
but much slower than linearly.
- Filled symbols (polygons) are 13% slower than unfilled symbols
(polylines).
- The extra indirection involved with embedding the user-defined
symbol in a model adds 25% to drawing time
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This software is provided subject to the following conditions:
1. NIWA makes no representations or warranties regarding the
accuracy of the software, the use to which the software may
be put or the results to be obtained from the use of the
software. Accordingly NIWA accepts no liability for any loss
or damage (whether direct of indirect) incurred by any person
through the use of or reliance on the software.
2. NIWA is to be acknowledged as the original author of the
software where the software is used or presented in any form.
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Modification History
Mark Hadfield, 2001-06:
Written.