[GRASS5] Re: vector point dataset

Hamish hamish_nospam at yahoo.com
Wed Nov 17 23:24:02 EST 2004


> We have a project (with authors of r.terraflow) for computing massive
> DEMs and your data set looks like the size that we are aiming at, but
> there may be other bottlenecks in GRASS than gridding so we need to
> look at those too.

[sorry if I'm mixing email threads here]


while hunting around in google for some digital sidescan sonar test data
so everyone can play along at home (didn't find any), I found this --
maybe of use to the sidescan folks:
  http://www.omg.unb.ca/~jhc/SwathEd.html


LIDAR data is an analogy re. data density and issues you might want to
think about while processing into a DEM and I think any GRASS method for
dealing with one dataset would deal with the other as well.

lidar sample data here:
  http://agassiz.la.asu.edu:8080/lservlet


Note along with x,y,z there might also be a return signal strength
number and timestamp to deal with.


Helena, Laura:
Creating massive DEMs into TINs - are you using Radial Basis Functions
for picking the optimum position and number of mesh points?

see e.g.,
  http://wwwradig.in.tum.de/people/buck/RBF/

(non-commercial-use C++ library + source)
 [perhaps could be talked into GPL?]




best,
Hamish




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