Finding/highlighting significant elevation change

Question

I am quite new to QGIS, so pardon if I use the wrong terminology etc.

I am scouting terrain to find new bouldering/climbing locations. My goal is to find significant elevation differences and highlight them. The idea is, that if there is a difference of 2+ meters in a very short distance, it would mean that there is something to climb there.

I have access to all kinds of data provided by Maanmittauslaitos, including elevation model, hill shade and LiDAR data. How can I process this data into something that would highlight or filter significant changes in elevation in a short distance?

Answer 1

Change rate of elevation is called slope. I think you are trying to calculate the slope of a terrain. You will need a Digital Elevation Model (DEM) to determine the slope. If you specify the distance e.g. 1 meter, your threshold slope will be arctan(2/1). You can calculate slope using the Slope tool in QGIS. The output of slope is in degree.

After calculating slope, you can use the Raster Calculator to select the areas having slope > arctan(2) i.e. in degree, slope > 63. The output will be in binary, where 1 is the true condition.