[GRASS-user] Local Relief Model tool

[Eric Goddard]

Hi Vaclav,

Your script looks very nice (much cleaner than mine!). I definitely need to
add some better error handling. I can see how using v.to.rast and
r.fillnulls may introduce fewer artifacts than v.surf--looking forward to
testing it. Based on the amount of helpful advice we've already received,
I'm leaning towards grass-dev for discussing the best methods to use and
merging of the scripts, but off-list is also ok.

Eric


On Wed, Sep 25, 2013 at 11:26 PM, Vaclav Petras <wenzeslaus at gmail.com>wrote:

> Hi Eric,
>
> actually I was working on the same module (named r.local.relief), so we
> have some duplication now. It is also based on [Hesse2010]. I was about to
> commit it to GRASS Addons but I need to write documentation first. For now,
> I'm adding the Python script into a attachment.
>
> I've quickly tested both and they give slightly different results. The
> other visible difference is the contours-to-really_smooth_elevation step.
> It seems that usage of r.fillnuls is faster than v.surfs. But this might
> require more testing as well as the different results do (probably caused
> by different elevation reconstruction). We can talk about it off-list if
> you prefer or at least on grass-dev list. And of course, we should discuss
> some merge of our scripts.
>
> As a side note I want also mention [r.shaded.pca] which I haven't
> announced yet but which is already in addons. It is based on [Devereux2010].
>
> Best,
> Vaclav
>
> [Hesse2010] Hesse, Ralf (2010): LiDAR-derived Local Relief Models - a new
> tool for archaeological prospection. Archaeological Prospection 17:67-72.
> [Devereux2008] Devereux, B. J., Amable, G. S., & Crow, P. P. (2008).
> Visualisation of LiDAR terrain models for archaeological feature detection.
> Antiquity, 82(316), 470-479.
> [r.shaded.pca]
> https://trac.osgeo.org/grass/browser/grass-addons/grass7/raster/r.shaded.pca
>
>
> On Wed, Sep 25, 2013 at 10:50 PM, Eric Goddard <egoddard1010 at gmail.com>wrote:
>
>> Hi all,
>>
>> I've created a grass python script that generates a local relief model
>> (LRM) from a high-resolution (such as from LIDAR) DEM based on Hesse, Ralf
>> (2010): LiDAR-derived Local Relief Models - a new tool for archaeological
>> prospection. Archaeological Prospection 17:67-72.
>>
>> I've tested it on several data sets of mine and it seems to be working
>> fine, however my data is limited to prehistoric Native American mounds. If
>> anyone else has some data they can test the tool on and report on the
>> results it would be much appreciated. The tool can be downloaded from
>> https://github.com/egoddard/r.surf.lrm.
>>
>> To install in a linux environment, I followed the instructions at
>> http://grasswiki.osgeo.org/wiki/GRASS_and_Python#Testing_and_installing_Python_extensions.
>> I haven't been able to find solid information on how users who don't
>> compile themselves can install an addon that isn't available via
>> g.extension. There is
>> http://grasswiki.osgeo.org/wiki/Compile_and_Install#Scripts, but I'm not
>> sure how that applies to Windows users. Any advice in this area would be
>> much appreciated.
>>
>> As a final note, I adapted this tool based on Rebecca Bennett's bash
>> script that was published in her dissertation. Thank you, Rebecca, for
>> answering all of my questions and for your efforts in trying to test it out
>> :)
>>
>> Eric
>>
>> _______________________________________________
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>>
>
>
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