file limit of lasmerge

[Pei Chun Lai]

hello everyone,

I have lots of las files to merge.  They are small data so I succeed to process files.

However, I am curious about file limit of lasmerge such as the numbers of files or size of merging files

Dose any one know about it ?

thank you

Pei_Chun

[Newcomb, Doug]

Pei,

If are merging to files that can be consumed by software that reads LAS 1.2, there is an approximately 4.2 billion point limit for the LAS 1.2 file format.

Doug 

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The opinions I express are my own and are not representative of the official policy of the U.S.Fish and Wildlife Service or Dept. of the Interior.   Life is too short for undocumented, proprietary data formats.

[Heidemann, Hans]

LAS 1.4 would theoretically support ~18,446,744,073,709,551,615 points.

How many FILES can be supported could be related to the architecture of the specific lastool being used, or by the operating system (i.e., how many file handles can be open simultaneously). Your system memory might play into that as well.

I suspect only Martin could definitively answer your question.

Karl

H. Karl Heidemann, GISP

Physical Scientist, Lidar Science

U.S. Geological Survey

Mundt Federal Building

47914 252nd Street

Sioux Falls, SD  57110

605-594-2861

kheid...@usgs.gov

"Nothing matters very much, and very few things ... matter at all."

- Arthur James Balfour

[Martin Isenburg]

Hello,

if you want to merge so many LAS 1.0/1.1/1.2/1.3 files whose total number of points exceeds 2^32-1 = 4,294,967,295 then you need to upgrade the format to LAS 1.4 as follows:

las2las -i many\*.laz -merged -set_version 1.4 -o merged14.laz

If you want to *quickly* check the total number of points in the set of LAS/LAZ file you want to merge into one file you should run:

lasinfo -i many\*.laz -merged -no_check

There should not be a limit on the number of files. That said - in general I advise people against merging too many LiDAR points into too large files. I consider this bad practice. For LAStools (and many other LiDAR softwares) can always "merge on-the-fly" using the '-i many\*.laz -merged' option. In my experience using reasonably sized tiles is a more practical way to manage large amounts of LiDAR.

Regards,

Martin @rapidlasso