I've a project involving a very small area (only a few hectares in size)
and I need topographic and flow data for it. Fortunately, abundant LiDAR
data are available for the area from 2007, 2009, and 2010. This will let me
determine if there are any changes in that period which I very much doubt.
Anyway, ...
I'm studying the wiki's LiDAR page to determine how best to proceed. My
data are in ESRI grid format, not LAS format. For example, the Bare_Earth
2007 subdirectory contains these files:
ls Bare_Earth/2007/be45123b1/
dblbnd.adf log prj.adf w001001.adf
hdr.adf metadata.xml sta.adf w001001x.adf
It's been several years since I've worked with topographic data in this
format and I don't recall which module imports them. Please point me in the
right direction. Also, pointers for the optimal modules for creating contour
lines and flow are appreciated because I'm confident much has improved since
I last did topographic and hydrological modeling.
Also, on the wiki page the top two references (Detailed description: here
(FOSS4G 2006) and Summarised version: LiDAR filtering with GRASS) have
broken links.
TIA,
Rich
On Mon, Aug 29, 2016 at 6:11 PM, Rich Shepard <rshepard@appl-ecosys.com> wrote:
I've a project involving a very small area (only a few hectares in size)
and I need topographic and flow data for it. Fortunately, abundant LiDAR
data are available for the area from 2007, 2009, and 2010. This will let me
determine if there are any changes in that period which I very much doubt.
Anyway, ...
I'm studying the wiki's LiDAR page to determine how best to proceed. My
data are in ESRI grid format, not LAS format. For example, the Bare_Earth
2007 subdirectory contains these files:
ls Bare_Earth/2007/be45123b1/
dblbnd.adf log prj.adf w001001.adf
hdr.adf metadata.xml sta.adf w001001x.adf
these were probably derived from lidar, but this is a raster format,
so you can import them in standard way using r.in.gdal/r.import
If you would get the original las files, you could have more control
over the processing if that's desired.
It's been several years since I've worked with topographic data in this
format and I don't recall which module imports them. Please point me in the
right direction. Also, pointers for the optimal modules for creating contour
lines and flow are appreciated because I'm confident much has improved since
I last did topographic and hydrological modeling.
for contours use r.contours and for flow accumulation use r.watershed,
but depends what exactly you want do. Some of these topics are covered
for example here:
http://ncsu-geoforall-lab.github.io/geospatial-modeling-course/grass/
Best,
Anna
Also, on the wiki page the top two references (Detailed description: here
(FOSS4G 2006) and Summarised version: LiDAR filtering with GRASS) have
broken links.
TIA,
Rich
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On Mon, 29 Aug 2016, Anna Petrášová wrote:
If you would get the original las files, you could have more control
over the processing if that's desired.
Hi, Anna,
I don't know if the original las files are available; I'll ask the agency
for them (and I have a las compression library that reduces storage volume
for the .las files.)
As I'm learning about LiDAR data I've no idea what I need in terms of
processing. These data are quite different from the 10m DEMs I've used for
years.
for contours use r.contours and for flow accumulation use r.watershed, but
depends what exactly you want do. Some of these topics are covered for
example here:
http://ncsu-geoforall-lab.github.io/geospatial-modeling-course/grass/
OK, then, nothing significant has changed external to the modules.
Thanks very much,
Rich
On 30/08/16 00:11, Rich Shepard wrote:
Also, on the wiki page the top two references (Detailed description: here
(FOSS4G 2006) and Summarised version: LiDAR filtering with GRASS) have
broken links.
Thanks for the heads up !
I've corrected the first, and found one publication which could correspond to the second, but am not sure. In any case, I've added that link instead of the dead one.
Moritz
On Mon, 29 Aug 2016, Anna Petrášová wrote:
If you would get the original las files, you could have more control over
the processing if that's desired.
Anna,
Please point me to something I can read to learn more about processing LAS
files. My web searches result in companies' instructions for LiDAR data in
their software.
TIA,
Rich
On Tue, Aug 30, 2016 at 11:57 AM, Rich Shepard <rshepard@appl-ecosys.com>
wrote:
Please point me to something I can read to learn more about processing LAS
files. My web searches result in companies' instructions for LiDAR data in
their software.
Here is set of lectures and assignments from NCSU partially dealing with
lidar:
http://ncsu-geoforall-lab.github.io/geospatial-modeling-course/topics/geomorphometry_basics.html
Here are my talks focused on some basic and some new GRASS GIS features
related to lidar:
https://wenzeslaus.github.com/grass-lidar-talks
And my paper dealing with some general and some specific point cloud
processing things:
https://www.researchgate.net/publication/304340172_Processing_UAV_and_lidar_point_clouds_in_GRASS_GIS
And as far as I understood from previous emails, you already looked at
GRASS wiki.
On Tue, 30 Aug 2016, Vaclav Petras wrote:
Here is set of lectures and assignments from NCSU partially dealing with
lidar:
http://ncsu-geoforall-lab.github.io/geospatial-modeling-course/topics/geomorphometry_basics.html
Here are my talks focused on some basic and some new GRASS GIS features
related to lidar:
https://wenzeslaus.github.com/grass-lidar-talks
And my paper dealing with some general and some specific point cloud
processing things:
https://www.researchgate.net/publication/304340172_Processing_UAV_and_lidar_point_clouds_in_GRASS_GIS
Vaclav,
Thanks. That will do nicely.
And as far as I understood from previous emails, you already looked at
GRASS wiki.
Yep.
I also just learned that here in Oregon the state charges for providing
raw LAS data to the public ($150+ for 50G, about 4 7.5 minute topo quads),
but provides ESRI-formatted data for free. Makes no sense to me, but I'm not
a bureaucrag. I'll use the Grid formatted data because I cannot justify
charging my client for the raw data.
Thanks very much,
Rich
Hi Vaclav,
On 30/08/16 18:28, Vaclav Petras wrote:
On Tue, Aug 30, 2016 at 11:57 AM, Rich Shepard <rshepard@appl-ecosys.com
<mailto:rshepard@appl-ecosys.com>> wrote:
Please point me to something I can read to learn more about
processing LAS
files. My web searches result in companies' instructions for LiDAR
data in
their software.
Here is set of lectures and assignments from NCSU partially dealing with
lidar:
http://ncsu-geoforall-lab.github.io/geospatial-modeling-course/topics/geomorphometry_basics.html
Here are my talks focused on some basic and some new GRASS GIS features
related to lidar:
https://wenzeslaus.github.com/grass-lidar-talks
And my paper dealing with some general and some specific point cloud
processing things:
https://www.researchgate.net/publication/304340172_Processing_UAV_and_lidar_point_clouds_in_GRASS_GIS
Could you add these references to the wiki page ?
Moritz
On Wed, Aug 31, 2016 at 7:56 AM, Moritz Lennert <
mlennert@club.worldonline.be> wrote:
Could you add these references to the wiki page ?
Done.
https://grasswiki.osgeo.org/w/index.php?title=LIDAR&type=revision&diff=23485&oldid=23478
On 31/08/16 15:55, Vaclav Petras wrote:
On Wed, Aug 31, 2016 at 7:56 AM, Moritz Lennert
<mlennert@club.worldonline.be <mailto:mlennert@club.worldonline.be>> wrote:
Could you add these references to the wiki page ?
Done.
Thanks !