I wish to create building footprints from the classification in our LAS files. I have filtered out the building points, using the point cloud filter. But I now trying to join the outermost points of the buildings, which I can't figure out how to achieve this. I understand that this may be a little hit and miss with the LAS classifications but I am happy to accept this. I am a inexperienced FME user.
Have a read of the following link Concave Hull and the Alpha Value, which was what I was trying to achieve by joining the Classified LIDAR building data and creating polygons around clusters of these points. Secondly as suggested look at this previously posted question Polygon from Point Cloud. Or review the attached image with my workflow, very important to read the metadata that comes with the LIDAR data. Some of the issues I found was the density of points and I had issues with the classification of data with incorrect values placed on points, causing my buildings to come out incorrect/slither polygons through buildings (but it did what i was trying to achieve)..
Best Way for free Building Footprint data. Use it once and you will get best output:
Go to Arc tool box add LAStools.tbx.
Drop down tool, you will see multiple of tools.
First click Las Ground provide Las file as input and run - It will give you output.
Now Run Las Height, provide Las ground output as input for Las height.
Now run Las Classify, Provide Las Height output as input for Las Classify.
Now run Las Boundary, Provide Las classify output as input for Las Boundary provide concavity - 8 best as per my study, Use option - Select Building.
Output will be your Building Footprint.
Note: Please don't change any options given in default by tool. I didn't change it and found the best output.