[GRASS-user] NVIZ - Visualization of buildings
Hi everyone, I'm trying to visualize a DEM that I've generated of the buildings of a city. In each cell I have the meters of elevation. When I try to see it with NVIZ I found that it makes something like interpolation, smoothing the corners like it was a DEM of terrain instead of hard edges (i don't know how to say it). Anyone knows how could i get a correct visualization of the buildings?? It would be very important to me getting it. I have the raster, and the vectorial with the areas and the attribute. Thanx!! Andres -- View this message in context: http://n2.nabble.com/NVIZ-Visualization-of-buildings-tp3917825p3917825.html Sent from the Grass - Users mailing list archive at Nabble.com. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Problem with Lidar Tools
Dear list, I am quite new to Grass and need to generate a DSM from Lidar data. Here is my workflow so far: v.in.ascii input=f:\lidar_test\single.csv output=single fs=, x=1 y=2 z=3 -z -b -t --o v.build single g.region vect=single v.in.ascii input=f:\lidar_test\first.csv output=first fs=, x=1 y=2 z=3 -z -b -t --o v.outlier input=single output=inlier_s outlier=outlier_s thres_o=5 soe=1 son=1 lambda_i=0.1 --o v.outlier input=first output=inlier_f outlier=outlier_f thres_o=5 soe=1 son=1 lambda_i=0.1 --o v.lidar.edgedetection input=inlier_s output=edgedetected see=400 sen=400 lambda_g=0.01 tgh=6 tgl=3 theta_g=0.26 lambda_r=1 --o v.lidar.growing input=edgedetected output=growing first=inlier_f tj=0.25 td=0.6 --o v.lidar.correction input=growing output=classified terrain=terrain sce=5 scn=5 lambda_c=1 tch=2 tcl=1 --o v.lidar.correction input=classified output=classified_it2 terrain=terrain_it2 sce=5 scn=5 lambda_c=1 tch=2 tcl=1 --o v.build terrain_it2 v.out.ogr in=terrain_it2 dsn=F:\lidar_test\terrain_it2 format=ESRI_Shapefile type=point lco=SHPT=POINTZ -e v.lidar.edgedetection classifies the data into cat 1 and cat 2 (=Terrain or Edge ?). This seams to work. The next step is v.lidar.growing. This tool should classify into 4 categories: TERRAIN SINGLE PULSE, TERRAIN DOUBLE PULSE, OBJECT SINGLE PULSE or OBJECT DOUBLE PULSE. But this does not happen. The cats still remain the same (cat1 and cat2) and the output looks identical to the output from v.lidar.edgedetection. v.lidar.growing seams to have no effect. Am I doing something wrong ? I have another problem with the parameters of the lidar tools (although I read Brovellis Managing and processing LIDAR data within GRASS). Can you give me some hints how to adjust the default values to very high res Lidar data (=50 points/m²). I raised see and sen parameter in v.lidar.edgedetection to 400 with the result, that the detected edges are now so wide, that they cover complete buildings. This way I can get rid of the most buildings but the result is not really satisfying and I guess the problem is false classification of v.lidar.growing Let me know if you need more infos. I am using GRass 6.3.0 on Windows. Can I expect improvements switching to 6.4 or switching to Linux ? Thank you very much !! kaipi -- View this message in context: http://n2.nabble.com/Problem-with-Lidar-Tools-tp3918684p3918684.html Sent from the Grass - Users mailing list archive at Nabble.com. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Fire Simulation bug
On Tue, Oct 20, 2009 at 10:16 PM, Adam Dershowitz
adershow...@exponent.com wrote:
I downloaded the 6.x firesimulation data set and demo script from:
http://www.hpcc.nectec.or.th/grass/download/data6.php (Yes, I am using the
script on that page, not the one that is included in the compressed file)
But, when I run it I get an error:
It gets as far as this:
r.random my_spread n=10 raster_output=my_path
Collecting Stats...
100%
Writing raster map my_path ...
100%
But then reports an error here:
r.spreadpath -v x_input=my_spread.x y_input=my_spread.y \
output=my_path
ERROR: option output: my_path exists.
It is correct that my_path exists, because it was created in the prior step.
But the documentation for r.spreadpath says in part:
output=name Name of raster map layer to contain output. Also can be used
as
the map layer of the input target points. If so used, the input
target point
map will be overwritten by the output.
It seems like the script is trying to use this as both the input and output,
as it says should be allowed. But it is instead giving an error. I also
tried to add --overwrite to r.spreadpath, but then I just get a completely
yellow window for the output with no paths at all.
Is there a bug in the script, or a bug in r.spreadpath?
I am not sure but in main.c I see
/* Set flag according to input */
if (path_mapset != NULL) {
if (head_start_pt == NULL)
/*output layer exists and start pts are not given on cmd line */
flag = 1;
/* output layer exists and starting pts are given on cmd line */
else
flag = 2;
}
else
flag = 3; /* output layer does not previously exist */
which could interfere with the libgis magic to handle overwriting of files.
Perhaps r.spreadpath wasn't updated accordingly?
Markus
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