| Re: MESH_DECIMATE [message #30003 is a reply to message #22279] |
Thu, 28 March 2002 00:25   |
R.Bauer
Messages: 1424
Registered: November 1998
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Senior Member |
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Karl Schultz wrote:
>
> "Reimar Bauer" <r.bauer@fz-juelich.de> wrote in message
> news:3CA21E59.1A63F0F6@fz-juelich.de...
>> Hi,
>>
>> did I miss something I like to use a function like mesh_decimate
>> but for vectors and not only for 3D Arrays.
>>
>> Did someone have already such a routines.
>>
>> Reimar
>>
>
> I'm not really sure what you are asking for, but the rest of this posting
> assumes that you want to decimate polylines, as opposed to polygons.
>
> MESH_DECIMATE is good for decimating things like regularly sampled height
> fields. The decimator removes vertices that are not as important as others
> in describing the height field. It will remove vertices in flat areas, for
> example. See the DECIMATE example that ships with IDL.
>
> The trouble is, there's no real easy way to do the same thing with
> polylines. Suppose that you had a highly detailed polyline (lots of
> vertices) that describes a coastline. You may want to simplify the line by
> reducing the number of vertices at the expense of some unwanted detail.
> There are various algorithms and approaches for the problem, but I don't
> think there's anything to directly do this in IDL.
>
> So, here's one of the tackiest things I've ever done with IDL. You can
> convert your polyline into a polygon extrusion, decimate that, and then take
> a border of your remaining extrusion as your decimated polyline. It is
> overkill, but is pretty cool nonetheless. Enjoy.
>
> Karl
>
Dear Karl,
what you described is what I like to have. The example is quite good.
thanks
Reimar
--
Reimar Bauer
Institut fuer Stratosphaerische Chemie (ICG-I)
Forschungszentrum Juelich
email: R.Bauer@fz-juelich.de
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a IDL library at ForschungsZentrum Juelich
http://www.fz-juelich.de/icg/icg1/idl_icglib/idl_lib_intro.h tml
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