Scale effects of digital elevation model on topographic indices

The accuracy of topographic indices derived from digital elevation models (DEMs) is of critical importance for eco-environment simulating and modeling based on DEMs. The objective of this study was to evaluate the accuracy of topographic indices derived from DEMs with different scales. Maps with scales of 1:10000, 1:50000, 1:100000, and 1:250000 were digitized and corresponding DEMs were produced using Arclnfo. Topographic indices including slope, aspect, profile curvature, and plan curvature were determined using the DEMs. Overall, certain topographic features were less perceptible on coarser DEMs than finer DEMs. Slope, profile and plan curvatures varied with the scales of the studied DEMs. Decreasing the scale of the studied DEMs produced lower slope gradients, narrower ranges in profile and plan curvatures. Further work will focus on the extraction and self-information of more other topographic indices and the scale impacts on different indices.