EFFECT OF BREAKLINES IN DIGITAL ELEVATION MODEL ON RESULTS OF SLOPE STUDIES FOR LAND PARCELS

The research compared two variants of a digital elevation model (DEM) in the triangular irregular network (TIN) version, one constructed with breaklines and the other without such lines. The data for DEM were derived from contour maps with a scale of 1 : 5000. The two models were employed in slope studies for 1236 farmland parcels. It was found that the absence of breaklines has an influence on the results of slope studies. For the study area, the differences with the results of slope studies based on the breaklines - containing DEM constituted up to 10%. In addition, using the latter model produced a stricter conformity between the contours of the dominant slope classes, drawn in the slope studies, and the real borders of land parcels. The research proved the usefulness of incorporating breaklines in the TIN versions of DEMs intended for the purposes of farmland analyses.