extracting building footprints with lasboundary

[Martin Isenburg]

hello,

for LAS files with already classified buildings points it is possible
to extract building footprints with lasboundary. this is not really a
full-fledged feature of LAStools but a capability that I stumbled
across when an engineering company asked me whether LAStools could be
used to extract building footprints.

here are the command lines:
lasboundary -i Dallas.las -keep_class 6 -disjoint -concavity 5 -o
Dallas_5_0.shp
lasboundary -i Dallas.las -keep_class 6 -disjoint -concavity 2.5 -o
Dallas_2_5.shp -holes
lasboundary -i Dallas.las -keep_class 6 -disjoint -concavity 2.5 -o
Dallas_2_5.kml -holes

here are the results:
http://www.cs.unc.edu/~isenburg/lastools/download/pics/lasboundary_buildings1.png
http://www.cs.unc.edu/~isenburg/lastools/download/pics/lasboundary_buildings2.png
http://www.cs.unc.edu/~isenburg/lastools/download/pics/lasboundary_buildings3.png
http://www.cs.unc.edu/~isenburg/lastools/download/pics/lasboundary_buildings4.png

here is the data:
http://bin.us.lizardtech.com/lidar/LT_LiDAR_Sample_Data.zip

one still has to simplified and clean-up the rigged polygons into nice-
looking rectified building shapes. does anyone know a good algorithm
for doing that?

cheers,

martin