[GRASS-user] newbie: processing lidar with r.in.xyz

[Hamish]

andrew haywood wrote:
> 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.

cheers, it is always nice to hear what it is used for.

> 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.

Just pass the intensity as the z= column instead of the height column?
That is why I called it "Column number of data values in input file" instead of "elevation values". It doesn't know/care what the data means.


> 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

what sort of metrics are you after?

> 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
> ...
> 
> I suspect I should start to learn python.

time well spent regardless; good return on investment if you like to think like that.

a nice place to start:
  10 minutes Python tutorial for programmers of other languages
  http://www.poromenos.org/tutorials/python


you could probably do what you want quite simply in awk as well, but I'd only really suggest that if you know UNIX or C already.


Hamish