Building detection
Menu: Analyze / Buildings
The building classification tool will identify points along vertical planes and classify them to class 6, which is the standard class for buildings. The algorithm is best used with points taken from ground-based scanners (terrestrial or mobile scanning) since any walls detected will appear vertical, whereas aerial surveys mostly only show rooftops: these won’t be detected by the algorithm as buildings.
Different settings are available for this function:
Slope tolerance (in degrees): Surface angle deviation tolerance accepted in a cell. A higher tolerance will allow rougher walls but may lead to more erroneous points in the classification.
Minimum cell size (in distance units): Minimal size of tiles used in this algorithm. This value determines the precision of the detection. The smaller the value, the more precise the ground will be, but the longer the process will take. The minimal size of the cell should be smaller than the size of a project cell, or else the size of the project cell will be used. The information about the project’s cell size can be found in the menu “File / Project info”.
Distance tolerance (in distance units): Maximum distance between a point and the mean plane of the wall for the point to be classified to the building class.
Starting point: Point where the algorithm will begin its process. It can be manually set or picked in the point cloud with the “Pick” button. Ideally a building point is selected in order to minimise processing time. If “Limit by radius” is used, the detection will be centered around this point.
Limit by radius (in distance units): Limits the zone to be processed around the starting point. This option is useful when trying the best combination of parameters in a project or for small areas which are distinct from the rest of the project.