[Liblas-devel] LAS Schema

[Mike Grant]

On 17/03/10 15:43, Howard Butler wrote:
> If we think this is legal, it would be a simple extension to allow the
> LASSchema to be written into a VLR that describes the layout of this
> extra data *within* the LAS file (as well as coincidently help me
> describe data in OPC, but that's an unrelated issue).

This sounds like a very neat extension to the LAS format that doesn't
break the existing specification.  In terms of liblas / reading standard
LAS files though, what would the purpose of this be?

I can see it definitely helps with your OPC problem and suggests a
(nice) possible future path for a new LAS [12].x, but I'm not sure if
it'd currently add to the fragmentation of formats problem that others
have mentioned.  If this were part of an official, well defined and
well-considered new specification, it sounds like a nice generic
solution to the variability of point data formats.  As an extra
libLAS-only format it risks being another variation, and one that might
be overridden by a LAS 1.4 / 2.0 spec at any time.

On that note, Martin's call for a 1.4 workshop also sounds interesting,
but I'd politely suggest avoiding getting a new spec done quickly - that
seems to have been the problem with 1.3.  Take the time to get feedback,
get community support and get it right.  As someone not particularly
versed in all the various LIDAR formats, it'd also be really interesting
to see a consolidated list of issues that need addressing - and
hopefully would help form an agenda for the workshop.

Pardon the notes of caution - as someone that's got LAS 1.3 files to
handle, I'm feeling a little burnt ;)

Cheers,

Mike.

P.S. we're going to provide a LAS 1.3 file for the sample archive soon,
though I understand we may not be able to read it for a long time!

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