Re: [GRASS-user] image spatial syncronization
Daniel wrote: > You could also try a software called regimy (or some other > spelling). If I recall correctly, it was developed by some > guys at inpe this seems to be the one: "REGEEMY" http://regima.dpi.inpe.br > and it finds matching control points between a set of images. > We have been using it for some old landsat images. Restrictive license, no linux binary since 2006 and no source code to recompile it for 64bit, so I won't bother to add it to the wiki (but if it's super useful I don't mind), but seeing they haven't touched in in years maybe the authors could be convinced to set it free? Hamish ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] [LAStools] lasground options -fine and -extra_fine: is the only difference processing speed?
Hello Adam, the '-fine', '-extra_fine', and '-ultra_fine' option specifies how much work the algorithm should invest to find the *initial* ground estimate that will get refined subsequently. As a rule of thumb you need a finer ground estimate the steeper your terrain. The option essentially defined how fine of a subgrid should be used to look for probable ground returns between the chosen step size. Each finer option quadruples the granularity of this subgrid (whose unrefined size is detmined by the step size). For very steep terrains extra fine is recommended but also for flat areas with subtle bumps in the ground the ultra fine setting can help to get better detail. For computing tree canopies, for example, in flat terrain the default granularity should be fine enough. Cheers, Martin On Jun 17, 2013, at 20:55, Adam Pryor wrote: > In lasground do the _fine and extra_fine options simply search a larger > proportion of the points to find ground points (requiring longer processing > time), or does it use a different method too? > > i.e. Is the only downside longer processing or could there be another benefit > for going with a coarser search? > > -- > Download LAStools at > http://lastools.org > http://rapidlasso.com > Be social with LAStools at > http://facebook.com/LAStools > http://twitter.com/LAStools > http://linkedin.com/groups/LAStools-4408378 > Manage your settings at > http://groups.google.com/group/lastools/subscribe > > -- Download LAStools at http://lastools.org http://rapidlasso.com Be social with LAStools at http://facebook.com/LAStools http://twitter.com/LAStools http://linkedin.com/groups/LAStools-4408378 Manage your settings at http://groups.google.com/group/lastools/subscribe ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] [LAStools] Lasclip on many files - can you skip creation of useless tiles with no overlap?
Hello Adam, currently lasclip seems to generate "empty" LAS/LAZ files when there is no overlap. It would be an easy feature to add a "remove file" operation once it becomes apparent the the produced file was empty. Can anyone think of a reason why we should keep the zero point files? Otherwise i will make what Adam suggests the default behaviour of lasclip in some future version ... Cheers, Martin @rapidlasso On Jun 17, 2013, at 21:16, Adam Pryor wrote: > Is there a way to prevent creation of useless files when applying lasclip > when working on a bunch of files using *.laz? > > I would like to run it on a whole directory of las tiles and only have new > files created for the tiles that actually have an overlap. > > (btw The youtube about spatial indexing with lax files has been very helpful > so far https://www.youtube.com/watch?v=FMcBywhPgdg) > > -- > Download LAStools at > http://lastools.org > http://rapidlasso.com > Be social with LAStools at > http://facebook.com/LAStools > http://twitter.com/LAStools > http://linkedin.com/groups/LAStools-4408378 > Manage your settings at > http://groups.google.com/group/lastools/subscribe > > -- Download LAStools at http://lastools.org http://rapidlasso.com Be social with LAStools at http://facebook.com/LAStools http://twitter.com/LAStools http://linkedin.com/groups/LAStools-4408378 Manage your settings at http://groups.google.com/group/lastools/subscribe ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] [LAStools] Cannot understand why lasoverage is not behaving as expected
Hello Adam, lasoverage is fully functional in the version that is online - except for the black diagonal lines that are added to the output raster. However, these only minimally affect your ability to judge the quality of the flight line alignment but let you evaluate the speed and efficiency of using LAStools for quality checking. The GPS time is not being used for lasoverlap. For lasoverlap it is important that an adequate step size is used and that the input contains correct populated point source ID fields. If the input is a set of flight lines this means that the option '-files_are_flightlines' needs to be set. Then there will be one single output raster. If the input are already tiled flightlines then each point must indicate which flight line it is from with a flight line unique point source ID. Then there will be one ouput raster per tile (unless '-merged' was specified). Any issues with lasoverlap are to be blamed either on user error or on poor documentation. (-: Regards, Martin PS: Also see the tutorial section on http://rapidlasso.com ... On Jun 17, 2013, at 21:20, Adam Pryor wrote: > I am still playing with the trial version until commercial license is > finalised... Should I expect lasoverage to be totally broken until the > commercial version is used? I remember seeing something about GPS time being > butchered on trial version? > > If you could confirm that it should be working in the trial version I will > persist and perhaps follow up with a detailed outline of the issues I am > having. > > Thanks. > -- > Download LAStools at > http://lastools.org > http://rapidlasso.com > Be social with LAStools at > http://facebook.com/LAStools > http://twitter.com/LAStools > http://linkedin.com/groups/LAStools-4408378 > Manage your settings at > http://groups.google.com/group/lastools/subscribe > > -- Download LAStools at http://lastools.org http://rapidlasso.com Be social with LAStools at http://facebook.com/LAStools http://twitter.com/LAStools http://linkedin.com/groups/LAStools-4408378 Manage your settings at http://groups.google.com/group/lastools/subscribe ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] [LAStools] Visualising data such as scan angle, gps time, etc
Hello Adam, the tools for gridding parameters other than the elevation are las2dem/blast2dem for intensity, slope, and RGB and lasgrid for scan_angle, classification, intensity, return counts, etc ... the GUI shows you the possible options in the selection box. You can then create a BIL or ASC raster and visualize this with your favorite raster software or with lasview ... lasgrid -i lidar.laz ^ -lowest -abs_scan_angle ^ -step 1 ^ -o minscanangles.asc lasview -i minscanangles.asc ^ -color_by_elevation2 ^ -win 1200 900 ^ -points 500 cheers, martin @rapidlasso On Jun 17, 2013, at 20:43, Adam Pryor wrote: > Is there a way to visualize things like scan angle or gps time in a las/laz > file. I dont want to view the raw data as ascii, I want to view it in a > convenient format, such as a raster or similar. > > e.g. Can I output a raster using las2dem where the cell values are populated > with these other datapoints instead of the usual elevation? Or is there some > nice GUI for viewing this other data? > > -- > Download LAStools at > http://lastools.org > http://rapidlasso.com > Be social with LAStools at > http://facebook.com/LAStools > http://twitter.com/LAStools > http://linkedin.com/groups/LAStools-4408378 > Manage your settings at > http://groups.google.com/group/lastools/subscribe > > -- Download LAStools at http://lastools.org http://rapidlasso.com Be social with LAStools at http://facebook.com/LAStools http://twitter.com/LAStools http://linkedin.com/groups/LAStools-4408378 Manage your settings at http://groups.google.com/group/lastools/subscribe ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] image spatial syncronization
Hi Miltinho, You could also try a software called regimy (or some other spelling). If I recall correctly, it was developed by some guys at inpe and it finds matching control points between a set of images. We have been using it for some old landsat images. Cheers Daniel On Jun 17, 2013 2:35 PM, "miltinhoastronauta ." < miltinho.astrona...@gmail.com> wrote: > WAW!!! Great suggestions, let try it! > > [ ]s > > milton > > 2013/6/16, Nikos Alexandris : > > Markus Neteler wrote: > >> > The easiest thing might be to use a SIFT algorithm in order to find > the > >> > GCPs automatically. Then use those as an input for i.rectify or > >> > similar. > >> > SIFT is used by Hugin for example. > > > >> > I used "autopano-sift-C" for a similar task (Fedora, rpmfusion-free > >> > repository). > > > > Hamish wrote: > >> link: > >> http://grasswiki.osgeo.org/wiki/Stereoscopic_analysis#See_also > > > > Really nice! Thank you, N > > > > > -- > Miltinho - m...@rc.unesp.br > Laboratório de Ecologia Espacial e Conservação - LEEC > Depto de Ecologia - UNESP - Rio Claro > Av. 24A, 1515- Bela Vista > 13506-900 Rio Claro, SP, Brasil > > Fone: +55 19 3526-9647 (office) 19 3526-9680 (lab) > Cel: 19 9853-3220 / 19 9853-5430 > > Depto Ecologia http://www.rc.unesp.br/ib/ecologia/ > > PG ECO & BIODIV > http://www.rc.unesp.br/ib/ecologia/posbiodiversidade/index.php > > CV > http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4792988H6&mostrarNroCitacoesISI=true&mostrarNroCitacoesScopus=true > > Google citations http://scholar.google.com/citations?user=OWX_2eAJ > ___ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user > ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
