haroldkumar

Extract roof form tool

Discussion created by haroldkumar on Mar 29, 2017
Latest reply on Jul 12, 2017 by k.puermayr_allee42

Hello!

 

I have a problem while using script for extraction roof forms in ArcGIS Pro, which was described here: 
Create elevation layers—Extract Roof Forms for Municipal Development | ArcGIS 

 

Although script works, it doesn't show true results. Less than 10% roofs are classified as hip or gable, and more than 90% are classified as flat which does not correspond to reality. I've computed mean slope for the roofs and I can see, that roof was classified as flat, although his mean slope is around 50 degrees. 

 

When it comes to input I have very accurate LiDAR data and created elevation layers with pixel 0,25m.

I've created completely new project and during creating LAS dataset I've set  my coordinate system (EPSG 3794).
Also in map properties I've changed everything to meters, but I thing that the problem still must be with coordinate system.

 

Key input data in extract roof form tool:
Minimum Flat Roof Area - default 250
Minimum Slope Roof Area - default 75
Minimum Roof Height - default 8

 

Because all these values are in feet, I've changed them to meters according to my data.

With parameters 25/7/2,5 (in order like above) tool extracted around 60 roofs. Rest ( more than 4000) are flat
I've made an experiment and run script with values 250/75/3 (like the input data would be in feets) and the result is 400 buildings classified (3800 buildings are still flat according to analysis). It is better but still only 8% buildings were classified as gable or hip. 

 

 

I have no idea where is the problem. Please help me.

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