[Qgis-user] TIN Interpolation

[Bernd Vogelgesang]

Hi folks,

i'm currently playing around with a set of LIDAR points (200m Grid, but  
for free).
Trying to "pimp" the model up, i also added some hight points from a  
topo-wms and wanted to add break lines and structure lines (streams).

Now i'm a bit clueless about the usage of the line features. The  
interpolation plugin always asks for a interpolation attribute, which  
doesn't make much sense cause those lines don't have them. They choice of  
the attribute field seems automatically limited to numerical fields (which  
makes sense for the z-values of points).

When i just create and pick a numerical field without values, the lines  
seem not to have any effect on the interpolation. When i use e.g the id,  
it has bizarre effects on the outcome.

So, how are line features supposed to work in interpolation plugin? Or how  
can i give structure lines hight values that make sense?

All tutorials and documentations (e.g.  
http://docs.qgis.org/1.8/html/en/docs/user_manual/plugins/plugins_interpolation.html  
) i found on that only cover the unproblematic usage of points and leave  
out the lines completely.

Thanx
Bernd

-- 
Bernd Vogelgesang * Siedlerstrasse 2 * 91083 Baiersdorf * +49-9133-825374