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Message: 7
Date: Thu, 29 May 2008 13:16:04 +1000
From: "andrew haywood" <[EMAIL PROTECTED]>
Subject: [GRASS-user] newbie: processing lidar with r.in.xyz
To: [email protected]
Message-ID:
<[EMAIL PROTECTED]>
Content-Type: text/plain; charset="iso-8859-1"
Dear List,
i am currently enjoying the flexibility of using r.in.xyz to process lidar
data over native forests in Victoria, Australia.Thank you hamish for such a
great tool.
At this stage I have 'binned' my data into 20m cells and calculated a number
of metrics (including 13 vegetation height percentiles p5 p10 p20 .. p90,
p95, p99) based on the z values.
What I was wondering is how can I calculate the mean intensity for the
associated height percentiles.
To get around this I have written a script in a proprietary stats package to
create the intensity metrics. However, I would prefer to use Grass and
opensource tools to do this binning
Any suggestions would be appreciated!!!!
My data is in the following format
x|y|ground|intensity|class|canopy_top|height
410774.45|5820999.93|773.3|23|10|766.0983886719|7.20161
410763.07|5820999.9|802.27|2|10|763.9434814453|38.3265
410765.47|5820999.94|773.11|90|10|764.2877807617|8.82222
410758.09|5820999.95|807.99|47|10|762.8372192383|45.1528
410748.12|5820999.93|760.89|8|10|760.5731811523|0.316819
Andrew,
At the risk of sounding thick, I'd like to know what "intensity"
represents in your context ... Regarding statistical packages, since R
is grass-linked, why not do the calcs in R?
Richard Chirgwin
...
...
...
I suspect I should start to learn python.
regards
Andy
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Message: 8
Date: Thu, 29 May 2008 11:17:48 +0800
From: "maning sambale" <[EMAIL PROTECTED]>
Subject: Re: [GRASS-user] Triangles polygons with Arc*
To: grass-user <[email protected]>
Message-ID:
<[EMAIL PROTECTED]>
Content-Type: text/plain; charset=UTF-8
Just curious if anybody encountered this issue with Arc*:
it's a common problem.
It does seem to be.
short answer: TINs stink. Raster maps created from TINs stink more.
My colleague used SRTM DEM converted to grid format of Arc
He mentioned that it is fairly common when you convert raster grids in
arc to vectors (shapefiles). Especially with very small areas like a
2-3 pixels. Will look into this further.
To all the others who gave me a list of Arc mailing list thanks! I am
reading a few right now.
cheers,
maning
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