Filtering and Binning with spfilter

Shawn Brown will put some information here about this demo. Until he does: What this program (spfilter) does is to average the points out into horizontal planes. Then we can connect them into a simplified streaming mesh that is much cleaner than a mesh of the original data.

As you can see below in these screenshots of the Ottawa data, spfilter, combined with a few other programs, is very effective at reducing noise and cleaning up the picture.

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Usage

To run these programs yourself, copy these command lines into your Command Prompt window, substituting your own filename for original_file.spb.

spfilter -i original_file.spb -o filtered_file.spb -ottawa -cellsize 1.0 1.0 1.0 -orig 0.0 0.0 0.0

The initialization of the spfilter program. Running this program will unfinalize the data, so it is necessary to run spfinalize to refinalize the file.

spfinalize -i filtered_file.spb -o finalized_file.spb

The data is now refinalized. Next we run spdelaunay2d to create a delaunay triangulation mesh of the filtered and finalized data points.

spdelaunay2d -i finalized_file.spb -o triangulated_file.smb

We could view the finished mesh right now, but in order to speed up the program and make the finished product cleaner, we will compress the data using smsimp and sm2sm. We decide to use 1% (0.01) of the original data, which we enact with the -t parameter:

smsimp -t 0.01 -m 16 -n 10000000 -i triangulated_file.smb -osmb -o simplified_file.smb (This should take a relatively long time, depending on your computer and the file used)

Then we convert the file:

sm2sm -i simplified_file.smb -o compressed_file.smc

Finally, we can view the finished file in sm_viewer:

sm_viewer -i compressed_file.smc

A close-up of the mesh we have just created:

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For more information, go to spfilter, or contact Shawn Brown.

-- ChristianStith - 01 Jul 2008