[OSGeo-Discuss] las spec doubt

[Howard Butler]

On Oct 31, 2013, at 2:38 AM, andrea antonello <andrea.antonello at gmail.com> wrote:

> Hi everyone, I hope this is not OT.
> I wanted to ask a short advice on a las file content problem.
> 
> I wanted to get a short comment about how GPS Week Time is seen in the
> las format.
> 
> Let's assume the las file format is prior to 1.2, so no encoding
> information is available to open possibility for adjusted gps time.
> 
> In that case, is it so that the Gps Week Time is just the seconds in
> the week, without any information about the week?
> I was under the assumption that the format of GPS Week Time would be
> "week.time" as content of the double, hence giving a full timestamp
> information.
> 
> I can't find a document exactly specifying this, the las specs just
> state: "GPS Time: The GPS time is the double floating point time tag
> value at which the point was acquired."
> 
> It is interesting, since I often found the header's date not being
> accurate (and seems to reflect the file modification date), making it
> impossible for me to define a unique timestamp.
> 
> Thanks for any comment, or link to docs.

This item is quite off-topic for this mailing list. I suggest emailing the following google group for access to more LAS implementors and knowledgable folks.

https://groups.google.com/forum/#!forum/lasroom

Howard