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

[Rebecca Bennett]

Hello Luis,

I'm about to commit a sacrilegious act on the GRASS-user list but it would seem that Martin Isenburg's LAStools software is more appropriate for this stage of your lidar processing.

http://rapidlasso.com/lastools/

My workflow is to do the tasks you mention below (including the point cloud visualization and DEM generation) in LAStools and then import the DEM / DTM to GRASS for all subsequent processing.


Best,
Rebecca


Rebecca Bennett
Postdoctoral Associate, Wired! Group
Department of Art, Art History and Visual Studies
Duke University, Durham, NC
www.pushingthesensors.com



>________________________________
> From: Luis Ramirez <lu.ramirez.c at gmail.com>
>To: grass-user at lists.osgeo.org 
>Sent: Monday, 26 August 2013, 9:03
>Subject: [GRASS-user] v.lidar.edgedetection,	v.surf.bspline and visualization issues
> 
>
>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!
>
>Luis
>
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