The circuit and the trees along it

Which spans of this 115 kV line need tree work first, and how much clearance each conductor keeps over the ground. Marengo County, Alabama, from public lidar.

USGS 3DEP lidar flown in 2020, about 5 points per square meter, with a NAIP photo laid over the surface. The towers are found in the point cloud, a catenary is fitted to every span, and every crown within 50 ft of the centerline is measured against the nearest conductor.

The line

Closest tree--

Crowns under 15 ft--

Crowns 15 to 25 ft--

Crowns over 25 ft--

Crowns on unresolved spans--

Lowest ground clearance--

Lowest on the main line--

Spans--

Towers--

Line length--

Mean span--

Crown counts are the crowns within 50 ft of the centerline, by clearance to the nearest conductor; the per-mile rate is over the whole line.

Span

Between--

Length--

Sag--

Min ground clearance--

Min tree clearance--

Show

Towers Conductors Trees by clearance Right of way Lidar points

Context

Gen-tie 13.0 mi on public roads to the 230 kV POI.

Method and limits

This is the workflow Trendline runs on surveyor lidar, here on public data: find the towers in the point cloud, fit the sag of the conductor for every span, then measure every tree along the line against the nearest wire.

Interpolated spans borrow their sag from the fitted spans, so their clearances are estimates. On the unresolved spans the conductor runs through canopy the lidar cannot see past, so those spans are drawn but not measured.

A lower distribution line runs about 50 to 60 ft (15 to 19 m) beside the 115 kV. It shows in the lidar points but is not modeled here.

Loading the corridor surface

Tree clearance

Under 15 ft15 to 25 ftOver 25 ftOn an unresolved span

Conductors, fitted catenary Interpolated span, dashed Unresolved span, gray Picked span Right of way, 50 ft each side Faint crowns are outside the right of way