[Liblas-devel] New win32 installer

[Mateusz Loskot]

Martin Vales pisze:
> Hi:
> 
>> 
>> We have discussed (together with Frank Warmerdam) some ideas about 
>> extracting CRS/projections part from libgeotiff as a tiny separate
>> library. Conclusion was that it's not a good idea.
> 
> 
> Perhaps i am a little silly asking this[?], but why liblas need 
> CRSs/projections????. Many companies have their own projection
> libraries and perhaps they want use it.

You can find the answer in LAS specification:

"The projection information for the point data is required for all data.
The projection information will be placed in the variable length 
records. Placing the projection information within the variable length 
records allows for any projection to be defined including custom 
projections. The GeoTiff specification 
http://www.remotesensing.org/geotiff/geotiff.html is the model for 
representing the projection information, and the format will be 
explicitly defined by this specification."

> For example if i want change the CRS of my las file i am going to use
> my favorite library to transform de file. If i want add CRS
> information i have a library for that (sharpmap, mapwindow, etc).

But you have to have tools for reading/writing/managing GeoTIFF
model of SRS stuff. The easiest is to use libgeotiff, so we can also use 
their rich set of dictionaries, etc.

> i don´t know but perhaps Neil wanted use his CRS library of the ERDAS
>  software.[?] Besides the proj format is not used in all software.
> *WKT* definition is most standarized in privative(esri) and free
> software (sharpmap).

The proj/WKT is just a input/output that users deal with. The LAS format 
uses GeoTIFF model (directory/records).

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org