Re: [GRASS-user] v.generalize dateline wrap problem
Dear all, Further to my question, here is the output of g.version: GRASS 7.1.svn (global_lonlat):~ g.version -g version=7.1.svn date=2014 revision=62762 build_date=2014-11-17 build_platform=x86_64-apple-darwin10.8.0 Thanks, Jed On 17 Nov 2014, at 15:34, Markus Neteler nete...@osgeo.org wrote: Hi, can you please send also the output of g.version -g to the list? thanks Markus ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] align large number of images in a automated way
Milton Cezar Ribeiro wrote 5. Unfortunatelly, as I have 18,000 images (and increasing), collect ground control point is not the solution That's only 12.5 minutes of video at 24 fps and the requirements you've described sound like a pretty typical camera stabilization problem. Why not take a look at camera tracking/stabilization software? In most cases such software will offer a high level of automation, however more importantly, at least from my perspective, they will also provide a good UI that will help you diagnose problems when the optimization process eventually goes off the rails. Something that you won't have if you opt for a completely command line solution. If you're looking for an open-source solution Blender has a decent tracker. The biggest feature it is probably missing for your application is being able to use ground control points in addition to image points. Most of the other commercial options do provide this feature, which would give you more reliable and accurate solves. Best, -- View this message in context: http://osgeo-org.1560.x6.nabble.com/align-large-number-of-images-in-a-automated-way-tp5154069p5154296.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] hydro-flatenning process ?
Helmut Kudrnovsky wrote r.in.xyz r.surf.idw v.surf.bspline v.surf.rst None of these, or any of GRASS's other surface interpolation tools that I'm aware of, consider breaklines. Although a feature request was filed 4 years ago: http://trac.osgeo.org/grass/ticket/793 You could probably generate hydro flattened surfaces separately and combine them with the DEM manually using the raster calculator, but unfortunately I don't think there is a one click button. -- View this message in context: http://osgeo-org.1560.x6.nabble.com/hydro-flatenning-process-tp5065095p5065874.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] Getting Started with GRASS Python Scripts
Martin Lacayo wrote #remove the location from disk print 'Removing location %s' % location_uri os.system(rm -rf %s % location_uri) Rather than rely on having 'rm' available you could also do: import shutil shutil.rmtree(location_uri) -- View this message in context: http://osgeo-org.1560.x6.nabble.com/Getting-Started-with-GRASS-Python-Scripts-tp5055380p5055759.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] Re: Generating DEM from bare ground LIDAR data: v.surf.idw or v.surf.bspline ?
stephen sefick wrote: I have a multitude of DEMs to generate at 1m resolution. Are there any references that compare v.surf.idw and v.surf.bspline? You might want to look at Bater and Coops (2009), they compared the performance of several different interpolation methods on lidar data. The short version is that for their data IDW and regularized spline interpolation produced the most extreme outliers while natural neighbor interpolation performed the best. In GRASS natural neighbor interpolation can be performed with the r.surf.nnbathy add-on. I hope this helps. Bater, C. W. Coops, N. C. Evaluating error associated with lidar-derived DEM interpolation. Computers Geosciences, 2009, v. 35, p.289-300 DOI: 10.1016/j.cageo.2008.09.001 -- Jed Frechette Lidar Guys -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/Generating-DEM-from-bare-ground-LIDAR-data-v-surf-idw-or-v-surf-bspline-tp5613649p5615341.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] Re: grass-user Digest, Vol 46, Issue 35
Michael Barton wrote: TIN's are a way of creating an elevation surface using vector polygons rather than rasters. When computers had slow processors, primitive displays, limited RAM, and limited disk space, they were a way of getting elevation in a way that optimized hardware limitations. They did so at a cost of resolution and simplicity of analysis/processing. I'm curious why you say TINs are used at the cost of resolution? What if I have a surface sampled by a dense irregularly spaced point data set, e.g. a lidar point cloud. If I create a TIN using a delaunay triangulation of those points the resulting model will exactly pass through all of the original data points with linear interpolations between. As a result it resolves all of the detail in the original data. In contrast, if I use a raster map to model the surface it will inevitably lead to some degree of aggregation as a function of the interpolation method I choose. The same is true if I want to incorporate linear features such as breaklines into the model. Of course, the question of which type of model is more useful for a given application is entirely separate. Best, -- Jed Frechette University of New Mexico Lidar Lab www.unm.edu/~lidar -- View this message in context: http://n2.nabble.com/Re-grass-user-Digest-Vol-46-Issue-35-tp4564699p4567229.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] Mask creation from sporadic data v.hull
JT-2 wrote: For a while now I have been trying to make an accurate mask for LiDAR points. As I am working with 1m resolution data I want the mask to be accurate (no more than 1m around the edge of the points/flight area). Awhile ago, inorder to solve this same problem, I hacked together a little script [1] that basically does a morphological closing on a raster map, e.g. the output of r.in.xyz. My shell scripting is pretty weak and I keep meaning to clean up the script and convert it to Python but it meets my needs for the moment so I keep finding better ways to spend my time. Maybe it will be of some help. Best, [1] http://bitbucket.org/jedfrechette/jdflib/src/tip/grass/r.closing -- Jed Frechette University of New Mexico Lidar Lab www.unm.edu/~lidar -- View this message in context: http://n2.nabble.com/Mask-creation-from-sporadic-data-v-hull-tp4186191p4190321.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
