Dear all, I have been trying to import a pointcloud into GRASS, by following Markus' direction as quoted below. The import of the pointcloud into GRASS works fine, but since I am quite new to GRASS, I have problems with the next logical steps - and in producing any meaningfull/viewable results.
I have uploaded the pointcloud-file: pc_xyzrgb.txt at a forum; http://uavmapping.com/forum/index.php?topic=17.0 It would be great if anyone would download the pointcloud and post a few examples of how to produse and display results. (Besides explanaition of the steps). Background: I have been writing a software/tool for georeferencing pointclouds from MS Photosynth/PMVS, by the use of 3D affine transformation. The objective is to use GRASS to produce digital elevation models out of the pointclouds, and to output the dem's into file-formats suitable for distribution to end users. Jørn, [email protected] > Date: Wed, 12 Jan 2011 15:29:41 +0100 > Subject: Re: [GRASS-user] From pointcloud to dem - help > From: [email protected] > To: [email protected] > CC: [email protected] > > On Wed, Jan 12, 2011 at 2:17 PM, Jorn Anke <[email protected]> wrote: > > > > Dear Grass users, > > > > I have a pointcloud form PMVS > > (http://grail.cs.washington.edu/software/pmvs/) consisting of near to 6 > > million points. > > > > The pointclouddata is georeferenced into world-coordinates (EUREF-89), and > > stored in a text file with the following format: X Y Z R G B. (RGB colordata > > can be deleted if required). > > > > What I want to do is to import the pointcloud into Grass 7.0, and to > > generate a surface modell/ dem, and to export the dem to a common > > file-format, e.g. ESRI SHP or Land-XML. > > > > I am quite new to Grass, so I would very much appreciate a brief description > > of the steps I will need to go through in order to obtain this. > > > First, import the point cloud with v.in.ascii. You can then filter the > points with the lidar tools to remove outliers (v.outlier) and obtain > a digital terrain model and a digital surface model > (v.lidar.edgedetection, v.lidar.growing, v.lidar.correction). The > v.surf.* modules can create a (raster) DEM by interpolating the > points. GRASS prefers raster maps for surface/terrain representation; > that also means that ESRI SHP or Land-XML being vector formats are not > really appropriate for a DEM. Common raster formats are e.g. GeoTIFF, > Erdas Imagine, or ESRI .hdr [1]. > > Markus M > > [1] http://www.gdal.org/formats_list.html
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