Creating Red Relief Image Maps using LAStools?

[bobby riley]

Group,

      Has anyone tried using LAStools to create Red Relief Image Maps?

      http://www.isprs.org/proceedings/XXXVII/congress/2_pdf/11_ThS-6/08.pdf

      If so, how successful were your efforts?

Thks,

Bobby

[Terje Mathisen]

bobby riley wrote:
> Group,
>
> Has anyone tried using LAStools to create Red Relief Image Maps?
>
> http://www.isprs.org/proceedings/XXXVII/congress/2_pdf/11_ThS-6/08.pdf

Interesting, this might in fact be more useful than a plain slope image
for my orienteering base maps, since the red-black axis clearly shows
the difference between a ditch and an earth bank.

>
> If so, how successful were your efforts?

I haven't tried yet, but I'm assuming that I can use a local DEM (which
I always generate at the same time as the slope image) to calculate a
concave/convex measure from the average height of the surrounding cells,
possibly scaled by distance, from the height of the current cell.

Thanks for the link!

Terje

--
- <Terje.M...@tmsw.no>
"almost all programming can be viewed as an exercise in caching"

[Václav Petráš]

Hi,

RRIM is interesting but I'm not sure if LAStools are the best way to do it. I would import data into GRASS GIS 7 as (raster) DEM and than use the tools there to accomplish things. There are also some ready-to-use tools similar to RRIM. The steps I used in GRASS GIS 7 to produce output which is very close to RRIM are:

r.skyview (similar to openness used in the RRIM article)

r.slope.aspect (to compute slope)

r.colors for slope raster (change color table to):

0% white

100% red

Then use 'Add various raster layers' button and 'Add shaded map' (d.shadedmap)

Skyview raster is used as 'reliefmap' and the red slope as 'drapemap'.

I know that this is not a LAStools solution but it is what I would use.

Vaclav

Links:
http://grass.osgeo.org/grass70/manuals/d.shadedmap.html
http://grass.osgeo.org/grass70/manuals/r.horizon.html
http://grass.osgeo.org/grass70/manuals/addons/r.skyview.html
http://grass.osgeo.org/grass70/manuals/addons/r.shaded.pca.html

Note that r.skyview and r.shaded.pca are in GRASS 7 Addons, so you have to install them separately.

Output of the steps above:

Thks,

Bobby

[Žiga Kokalj]

Dear all,

We have produced an easy to use, standalone and free tool for visualizing
raster relief data (Relief Visualization Toolbox
<http://iaps.zrc-sazu.si/en/svf> ). We have only implemented techniques
proven to be effective for identification of small scale features. They are
shortly described in the readme file
<http://iaps.zrc-sazu.si/sites/default/files/rvt_1.0_0.pdf> , and in more
detail in a comparative book chapter (Kokalj et al. 2013. "Visualizations of
Lidar Derived Relief Models." In: Interpreting Archaeological Topography.
100-114. Oxford: Oxbow Books). Openness is one of them, but because it
completely remove a general sense of topography I'd recommend using
anisotropic sky view factor. Which technique to use is a big issue in
archaeology and we've found you usually need a combination of them, and use
of various is needed for different features on different terrain types. If
you are interested in more details I'd be happy to discuss :)

With best wishes,

Ziga
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Ziga Kokalj, PhD
Institute of Anthropological and Spatial Studies
Scientific Research Centre of the Slovenian Academy of Sciences and Arts
Novi trg 2, SI - 1000 Ljubljana, Slovenia
Centre of Excellence for Space Sciences and Technologies
Novi trg 2, SI - 1000 Ljubljana, Slovenia
web: iaps.zrc-sazu.si
e-mail: ziga....@zrc-sazu.si
tel: +386 (0) 1 47 06 458
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~