[Liblas-devel] How can I find out which attributes are populated in a LAS file?

[Howard Butler]

> On Jul 10, 2015, at 6:17 AM, Kostis Kyzirakos <Kostis.Kyzirakos at cwi.nl> wrote:
> 
> Hi there,
> I am using the C api of liblas to ingest LAS/LAZ files. The files that I
> want to ingest do not have a consistent schema (i.e., all files have X,
> Y, Z information, some of them have color information and some of them
> have intensity information).
> 
> Is there a way to find out which dimensions are actually present in a
> LAS file without accessing all points?
> 
> As far as I know, I can use the data format id to find out whether the
> file contains time and color information. Is there something similar for
> the other attributes? Is there a way to find out in advance if a LAS
> file has information about the rest attributes like intensity,
> return_number, number_of_returns?

Other than as you describe for the format id, there isn’t a standard way to do this. Many softwares keep their own VLRs with some statistics to do this, but as mentioned, it isn’t standard.

Howard