Histofit : Slope angle frequency analysis in mapping rockfall hazard
Histofit is an Excel-based application that computes the most-likely Gaussian curves in an iterative way, so that the sum of those gaussian curves fits the all kind of considered data distribution. In the case of mapping rockfall hazard at regional scale, Potential rockfall initiation areas are identified by analysing the slope angle distribution (SAD) of the topography. The fitting process is done by minimizing the standard error using optimisation processus of the Excel solver. This tool enables to fit the sum of up to 5 gaussian curves to a target function represented here by a slope angle histogram. It contains moreover the possibility to display the Gaussian curves under the target curve. In order to help the Excel application getting the best-fitting Gaussian curves and to be able to start fitting the target curve, initial parameter, such as the number of Gaussian curves with their estimate mean and standard deviation must be set manually. These can be defined according to the shape of the target function, where the trend obviously shows some unsteadiness in its distribution.
Disclaimer
Histofit is a freeware developped at the Institute of Geomatics and Risk analysis (IGAR) at the University of Lausanne by the Prof. Michel Jaboyedoff. No warranty is made by IGAR for the functioning of the software and no responsibility is assumed by IGAR in the use of this tool.
Support
There is no formal ongoing support for this freely distributed public domain software. However, if you have any questions or suggestions, please contact michel.jaboyedoff@unil.ch
Publication
Loye, A., Jaboyedoff, M., and Pedrazzini, A.: Identification of potential rockfall source areas at a regional scale using a DEM-based geomorphometric analysis, Nat. Hazards Earth Syst. Sci., 9, 1643-1653, 2009.
Michoud C., Derron M.-H., Horton P., Jaboyedoff M., Baillifard F.-J., Loye A., Nicolet P., Pedrazzini A. and Queyrel A.: Rockfall hazard and risk assessments along roads at a regional scale: example in Swiss Alps. Natural Hazards and Earth System Sciences, 12, 615-629, 2012.
Download: Histofit v 1.0