The diploma thesis deals with an illegal landfill of waste at the area of Ljubljansko barje, which has already been rehabilitated. GNSS terrain measurements have been performed to get the positions on the landfill waste for the volume computation. The first part of the thesis incorporates a short description of the Ljubljansko barje and describes the recent Slovenian project Let’s clean Slovenia in one day. The second part includes steps of data processing with final volume computation using Delaunay triangulation. According to the landowners’ information the landfill of waste deposited in the excavation at a depth of several meters. So we estimated also the volume, where the waste was located below the ground level. Landfill volume was calculated by several different criteria’s in order to get an estimation of how the number as well as distribution of points affects the final calculation. At the end we propose further activities at the same area, that acquire also landfill waste subsidence estimation.