[GRASS-user] Mask creation from sporadic data v.hull

[John Tate]

Hi all,

For a while now I have been trying to make an accurate mask for LiDAR points. 
As I am working with 1m resolution data I want the mask to be accurate (no 
more than 1m around the edge of the points/flight area).

The data is wavy around the edges, due to a windy flight when the data was 
collected, so v.hull ignores the waves and joins the crests, adding vast NULL 
areas to the mask. Also, there are up to 10m holes within the individual 
swaths.

r.in.xyz at 5m resolution has given me the best results so far as final 
accuracy masks, but not for the processing as I want holes within the data 
filled with v.surf.rst.

I have looked at v.delaunay and v.voronoi too, but both need topology built 
and don't have similar outputs to v.hull regarding vast NULL areas. This is ok 
for 1km tiles, but I want to process each swath separately (study on swath 
accuracy) and these can be c.5million points each.

Does anyone know if there is way to do this accurately without manually 
digitizing? Have I missed something in the book/manual?

Cheers

John