[R-sig-Geo] read function for LAS data

[Etienne Bellemare Racine]

This is interesting, I'll try your code on my lidar files in the next 
few days.

  2010-06-04 22:36, Michael Sumner wrote :
> Thanks Alex, I will eventually post this to a broader audience.
>
> I've used liblas and lastools, but the aim here is for a pure R
> implementation that is built directly from the LAS specification
> without 3rd party tools.
>    

What might be of interest in using liblas is that it provides support 
for many las versions and they plan to provide support for some versions 
to come (conditional to funding) so having an R binding might be of 
interest here. They are also working on the integration of a spatial 
index which would allow easier handling of large files. I must say I 
don't know how hard writing a wrapper for R might be for that particular 
tool.

To other issue I see here is that R is loading the whole file in memory, 
so if you can manage small files, that might not be that easy with 
(standard) larger ones. Don't you think ? Did you give a try to the R 
SAGA package. There is a module for loading las files but again, I don't 
know how it manages memory. I guess that it could be possible to use 
some sort of ff package to handle bigger files, but that's just on the 
top of my head.

Etienne

> The R code already works quite well to extract x/y/z/time/intensity,
> it just needs some extra work to tidy up and generalize things and
> ensure that very big datasets can be read.
>
> Cheers, Mike.
>
>
> On Sat, Jun 5, 2010 at 6:07 AM, Alex Mandel<tech_dev at wildintellect.com>  wrote:
>    
>> On 06/03/2010 07:54 PM, Michael Sumner wrote:
>>      
>>> Hello,
>>>
>>> I'm looking for interest in this functionality and eventually working
>>> it into a package.
>>>
>>> I don't actually use LAS data much, and only have one example file so
>>> I'm hoping others who do or know others who would be interested can
>>> help. I have previously posted this to r-spatial-devel.
>>>
>>>        
>> I think there are people who would use it. You might want to have a look
>> at http://liblas.org/ (some of the same people that do gdal/org work)
>> Wrapping this library might be a good approach. There are example files
>> available too.
>>
>> Thanks,
>> Alex
>>
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