I have a task I would like to solve with GRASS GIS 7, if somehow possible. I want to create a cross section from a landslide - and would like to calculate the area of that cross section/profile. Any way to do this easily without using ArcGIS?
If I understood the question right, take a look at r3.cross.rast which creates cross section 2D raster map from 3D raster map based on 2D elevation map. From that 2D map you can generate the area report.