Automatic Powerline Classification

Automatic Powerline Classification is part of the Classification tool within the Automatic Point Cloud Analysis tool.

The Powerline Classification option in the Automatic Point Cloud Analysis tool can automatically detect power lines in high density lidar data. This density is typical of terrestrial lidar, mobile lidar, or uav collected lidar point clouds. Photogrammetric point clouds, such as those generated using Pixels to Points, may also have this density, but they do not typically have the reconstruction detail to precisely identify powerlines.

Once your settings have been determined for all desired classifications, click Classify Features to begin processing.

Classification and Extraction Shared Settings:

Power Line classification shares two settings with the Feature Extraction tool:

Minimum Powerline Length

Sections of powerline that are shorter than this set length will be ignored. Increase this value when using low density point clouds.

Minimum Height Above Ground

Use this field to specify the minimum height above ground that a point has to be in order to consider it as a possible powerline point.

Powerline Classification Settings

The point cloud should have ground points already classified prior to performing this classification. Global Mapper will do this automatically when the ground classification option is also selected to run simultaneously.

The powerline classification algorithm compares segments of data (bins) to best fit lines, to classify points as powerline that are within a minimum distance from a best-fit line. It recommended to run this data on point clouds with at least 20 points /m².

 

Maximum Distance from Best Fit Line

The algorithm works by creating a "best fit" line where it estimates the power line to be, then compares the points to the line. This setting determines the maximum distance (in meters) away from the best-fit 3D line of points with similar elevations in a bin, that any points can be and still be considered powerlines.

Bin Size to Check for Linear Points

This setting controls the size of each bin (meters per edge) when evaluating points to see if they follow a linear pattern. Overwrites shared resolution setting.

Maximum Slope (Height Change per Meter)

Use this field to specify the maximum difference in elevation allowed per meter to consider points as possibly part of the same powerline segment. Basically, it measures the amount of slack in the powerline. The default value is 0.5m, which allows for a change in elevation of 0.5m over a 1m distance between points. You might wish to specify a slightly larger value if your data is noisy.

Reset Existing Pole Points to Unclassified at Start

Resets the classified pole point data to unclassified at the beginning of processing.