The QGIS plugin Seilaplan is a GIS-based forest management support tool for designing and optimizing cable road layouts. It was developed in 2012 as part of Dr. Leo Bont's dissertation at ETH Zurich and has been under further development by him at the Swiss Federal Institute for Forest, Snow and Landscape Research WSL since 2017.
The abbreviation "Seilaplan" stands for cable road layout planner. Using defined start and end coordinates, machine data and other technical skyline parameters, the tool calculates the optimal cable road layout based on a digital elevation model. The position and height of the supports, as well as the most important characteristic values of the cable roads are determined. The load path curve is calculated using Zweifel's (1960) algorithm, a catenary method. In the research project "New Foundations for Efficient cable road-Layout Planning" completed in 2020 by the Sustainable Forestry Research Group (WSL) under the direction of Dr. Leo Bont, calculations of load-path curves according to Zweifel (1960) achieved significantly more accurate results than with the widely used method of Pestal (1961).