lasclip

[Möst, Karin (LDBV)]

Hi,

I use lasclip to change the classification of building points.
Is it an advantage, to put a spatial index on the lidar files first?
Is there a limitation to the number of buildings in the shapefile for the classification?

Thank you
Karin

[Jochen Rapidlasso]

Hi Karin,
a) Using index files
I did a small test:

Running a sample lasclip without indexing:
>> 54 sec.

Creating an index:
>> 13 sec.

Running the same sample with this index:
>> 45 sec.

So I would say: If you have to touch a file just once in a workflow the index does not increase the overall performance.
If you touch the file multiple times the index most likely improve the performance.

b) limitation of SHP files
The SHP file format is a funny one - the numbers in the file itself are 32 bit signed integers - so they will hold
everything up to ~2gig, the used DBF database for attribute has limitation of 1G entries and 2G in total file size.
Anyway, it is wise to split your files to small portions for easy handling and may parallel processing.

Best,

Jochen @rapidlasso