True Length from DEM

Description

This component calculates the true three-dimensional length of line features by accounting for the elevation changes recorded in a Digital Elevation Model (DEM). Unlike a flat 2D measurement, the true length follows the terrain surface, giving more accurate distances for paths, roads, or pipelines over hilly ground.

The result is added as a new attribute column on the input line features.

Inputs

• DEM raster [Raster] — the elevation raster used to sample heights along each line
• Line features [Dataset] — the line dataset to measure
• NoData handling [Selection] — how to treat missing elevation values: Skip (ignore gaps), Nearest (use the nearest valid elevation), or Flag (mark affected lines as invalid)
• Length unit [Selection] — the unit for the output distance column (meters or feet)

Outputs

• Result dataset [Dataset] — the input lines with an added true-length attribute column

Use Cases

• Calculating the hiking or cycling distance of a trail that crosses uneven terrain
• Estimating the actual cable or pipe length needed for infrastructure that follows slopes
• Comparing flat 2D distances with terrain-corrected 3D distances for survey validation