<html>
<head>
<style><!--
.hmmessage P
{
margin:0px;
padding:0px
}
body.hmmessage
{
font-size: 10pt;
font-family:Tahoma
}
--></style>
</head>
<body class='hmmessage'>
Dear all,<br><br>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.<br><br>I
have uploaded the pointcloud-file: pc_xyzrgb.txt at a forum;
http://uavmapping.com/forum/index.php?topic=17.0<br><br>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).<br><br><br>Background:<br>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.<br><br><br>Jørn,<br>jornanke@hotmail.com<br><br><br>> Date: Wed, 12
Jan 2011 15:29:41 +0100<br>> Subject: Re: [GRASS-user] From pointcloud to dem
- help<br>> From: markus.metz.giswork@googlemail.com<br>> To:
jornanke@hotmail.com<br>> CC: grass-user@lists.osgeo.org<br>> <br>> On
Wed, Jan 12, 2011 at 2:17 PM, Jorn Anke <jornanke@hotmail.com>
wrote:<br>> ><br>> > Dear Grass users,<br>> ><br>> > I
have a pointcloud form PMVS<br>> >
(http://grail.cs.washington.edu/software/pmvs/) consisting of near to 6<br>>
> million points.<br>> ><br>> > The pointclouddata is
georeferenced into world-coordinates (EUREF-89), and<br>> > stored in a
text file with the following format: X Y Z R G B. (RGB colordata<br>> >
can be deleted if required).<br>> ><br>> > What I want to do is to
import the pointcloud into Grass 7.0, and to<br>> > generate a surface
modell/ dem, and to export the dem to a common<br>> > file-format, e.g.
ESRI SHP or Land-XML.<br>> ><br>> > I am quite new to Grass, so I
would very much appreciate a brief description<br>> > of the steps I will
need to go through in order to obtain this.<br>> ><br>> First, import
the point cloud with v.in.ascii. You can then filter the<br>> points with the
lidar tools to remove outliers (v.outlier) and obtain<br>> a digital terrain
model and a digital surface model<br>> (v.lidar.edgedetection,
v.lidar.growing, v.lidar.correction). The<br>> v.surf.* modules can create a
(raster) DEM by interpolating the<br>> points. GRASS prefers raster maps for
surface/terrain representation;<br>> that also means that ESRI SHP or
Land-XML being vector formats are not<br>> really appropriate for a DEM.
Common raster formats are e.g. GeoTIFF,<br>> Erdas Imagine, or ESRI .hdr
[1].<br>> <br>> Markus M<br>> <br>> [1]
http://www.gdal.org/formats_list.html<br> </body>
</html>