Buildings
Not Lite
Buildings routine classifies points on building roofs which form a planar surface. The routine requires that ground points have been before. It is also advisable to classify points above the ground into a separate class, so that this class contains points in an elevation range above ground where building roofs are included.
The routine starts from empty areas in the ground class and tries to find points on planar surfaces above these areas.
SETTING |
EFFECT |
|---|---|
Ground class |
Point class that contains points on the ground. |
From class |
Source class(es). |
To class |
Target class. |
Inside fence only |
If on, points inside a fence or selected polygon(s) are classified. |
Accept using |
Defines how easily a group of points is accepted as building roof points. The more strict the rules, the closer the points must follow a plane surface. |
Minimum size |
Smallest size of a building footprint. Points are only classified if the footprint area of the whole building is larger than the given value. |
Z tolerance |
Minimum elevation difference of a point from the plane fitted through the points on a roof. The value is related to the noise level of the points on roof planes. |
Use echo information |
If on, the echo type attribute of laser points is considered in the classification process. This can support the classification because points on roofs mostly belong to the echo type ‘only echo’ whereas vegetation usually contains lot of ‘first of many’ and ‘intermediate’ echoes. |
Use dimension |
If on, software identifies surface points using normal vector dimension. Planar dimension points gain higher weight in classification. Dimension can help avoiding complex vegetation points in classification. This option requires normal vectors. |
Use vegetation index |
If on, software identifies vegetation points using vegetation index. Low vegetation index points have higher weight in classification. Suitable Limit for the index formula Type can be identified coloring points by vegetation index. This option requires color information. |
