Rock head elevation model of northern Estonia

The last rock head elevation model covering the whole of Estonia was compiled about 40 years ago. This model relied on data from 2500 boreholes and excavations and geophysical data. Using the freely accessible present information about more than 34 640 borehole datapoints from the carbonate area, we updated the 40-year-old model. The Devonian sandstone area was disregarded in this work as it needs a different approach of interpolation due to a considerably lower data density and a different behaviour of erosional processes. During this work, the data were filtered for identifying errors and the filtered dataset was interpolated numerous times using the Topo to Raster and Spline methods available in ArcGIS software. The results were compared statistically and by employing the available rock head elevation models. The results from the Topo to Raster method proved to be superior in the correlance next to the partially mapped 1:50 000 rock head elevation model, and the best-suited model was applied to the outcrop area of carbonate rocks in Estonia. Compared to the last rock head elevation model, the new one describes the carbonate bedrock topography in much more detail. It does not match the 1:50 000 scale geological map in all places, possibly due to a much more detailed data set but also because of the errors that may have passed the filtering process during the early stages of work. The rock head elevation model is an important part of GIS-based geological mapping and one of the first steps in producing 3D geological models.