[Liblas-devel] Clipping

[Giglierano, James [DNR]]

Pete thinks this isn't needed. He's probably right....

-----Original Message-----
From: Howard Butler [mailto:hobu.inc at gmail.com] 
Sent: Wednesday, April 09, 2008 11:40 AM
To: Giglierano, James [DNR]
Cc: Liblas-devel at mail.hobu.net
Subject: Re: [Liblas-devel] Clipping

Ok.  I'll add the ability to las2las to clip on Z's.

Something like

--clip X1 Y1 X2 Y2 [Z1 Z2]

with the Z values being optional.

Sound sufficient?


On Apr 9, 2008, at 11:36 AM, Giglierano, James [DNR] wrote:
> Actually, we have seen regular cases of sunlight reflecting off water
> surfaces to the lidar sensor.  Since the sunlight is always on, it  
> gives
> a false elevation of the airplane's height.  These are usually  
> filtered
> out for the bare earth classification by the vendor, but they still
> appear in the first return data, maybe others.  Unless you are aware
> that this happens, it can be disconcerting when it first appears.  A
> height filter might be useful, or something to catch and remove  
> outliers
> such as this.
>
> -----Original Message-----
> From: liblas-devel-bounces at mail.hobu.net
> [mailto:liblas-devel-bounces at mail.hobu.net] On Behalf Of Mateusz  
> Loskot
> Sent: Wednesday, April 09, 2008 11:24 AM
> To: Liblas-devel at mail.hobu.net
> Subject: Re: [Liblas-devel] Clipping
>
> Howard Butler wrote:
>>
>> On Apr 9, 2008, at 10:32 AM, Mateusz Loskot wrote:
>>> Hi,
>>>
>>> Do we have a tool that can clip LAS file to given extent of XYZ
> pairs?
>>> I imagine to have something like:
>>>
>>> las2las --min X1 Y1 Z1 --max X2 Y2 Z2 --in file.las --out  
>>> clipped.las
>>
>> Yep, but it only clips on x and y, not z.  I'm not sure you would  
>> want
>
>> to clip z's out, but that could be easily added.
>>
>> http://liblas.org/browser/trunk/apps/las2las.c#L55
>>
>> las2las -i file.las --clip X1 Y1 X2 Y2 --out clipped.las
>
> Hobu,
>
> That's exactlu what I was looking for. You are right, clipping by Z
> value is usually not very useful.
>
> Cheers
> -- 
> Mateusz Loskot
> http://mateusz.loskot.net
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