[GRASS-user] v.lidar.edgedetection, v.surf.bspline and visualization issues

Luis Ramirez lu.ramirez.c at gmail.com
Mon Aug 26 06:03:22 PDT 2013

Hi there,

I´m being working with Grass Gis just for few weeks. I´m trying to 
generate a dsm and dtm from LIDAR data. I imported my data as LAS and i 
was following the steps explained in the Grass Gis Book of neteler and 
mitasova. However, I'am having some problems that are transforming an 
easy task into a time-consuming-nightmare. the first thing that I do not 
understand is why v.lidar.edgedetection works under Grass Gis 6.4. and 7 
instaled in a Virtual machine with Ubuntu but not in Grass Gis 6.4. and 
7 in a windows 7 Computer. after calculating the first two regions (from 
9) it crashes. I tried to increment the parameters "see" and "sen" up to 
the value 10. it is able to calculate a bit more but it still craches. 
after googleing it i Just get information about a bug detected in 2006. 
I would really apreciate to be able to run this module in a windows 7 
computer. do you maybe have a clue?
the second issue is related to v.surf.bspline. I am using a very small 
map of 1km2 with 118798 points for testing (the goal is to use the 
procedure for a map at least 20 times larger than this one). However, 
Grass Gis 6.4 and 7 (for Ubuntu and For Windows) show me a warning 
message. it says that it could take too long depending on the amount of 
points. I already tried with different values for the parameters" sie" 
and "sin" but it doesnt get any better. I just left the computer 
calculating for few hours but I´m not really getting any result. do 
anyone have an Idea what I´m doing wrong?
Finally, I´m being trying to get a 3D visualization of the points but 
both the monitors of the GUI and the wxs ended up crashing before I can 
see a thing. is that a known problem? there is any known reason for such 
a problem or even better, a solution or an alternative?

Thank you in advance!


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