[Liblas-devel] Re: las2txt question

[Mike Grant]

Hi all,

A simple parseable header definitely sounds nice, though I'd share
Martin's concerns about a bullet hole in our feet re: creating a first
class text based LIDAR format.

+1 to parseable --header-only and --data-only outputs though, for
interoperability purposes.

On 25/11/10 01:07, Angley, William [USA] wrote:
> *       On the flip side, being able to transform .las data into GML
> or KML formats would be extremely helpful at times.  Among other
> things, this would allow for the display of LiDAR data in Google
> Earth and via MapServer.

This would be a very nice thing to have, though it's probably a separate
thread :)

> a file format design issue.    The combination of simple, open
> standards that I've suggested (YAML + tab-separated values) is

Just a note but, as I understand it, YAML parsers blow up when you feed
them anything with tabs, so one would have to programmatically prune the
header from the data (assuming it's in one stream ; two streams would be
fine).

> I don't know how well it would work in general use, but it seems
> worthwhile to note that word processing file formats have been
> evolving in this direction for some time.  Both OpenDocument Format
> and Office Open XML are compressed, structured text successors to
> binary file formats.

I'd echo Martin's comment that text files aren't very efficient for
storage (unless compressed) but they're also very bad for random access
(which compression makes worse).  Even a few minutes of an aircraft
flying produces hundreds of MB of binary data (approximately doubles in
conversion to ASCII, for discrete data).  All the indications are that
that'll get bigger in the next few years - full waveform (will increase
the multiplier), higher pulse rates, etc.

Cheers,

Mike.

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