Ik Woo

The effect of spatial resolution on the accuracy of landslide susceptibility mapping: a case study in Boun, Korea

The authors have evaluated the effect of spatial resolution on the accuracy of landslide susceptibility mapping. For this purpose, landslide locations were identified from the interpretation of aerial photographs and field surveys in the Boun region of Korea. Topography, soil, forest, geological, lineament and landuse data were collected, processed, and constructed into a spatial database using GIS and remote sensing data. The 15 factors that influenced landslide occurrence were extracted and calculated from the spatial database at 5, 10, 30, 100 and 200 m spatial resolution. Hazardous landslide areas were analyzed and mapped using the landslide-occurrence factors by employing a probability models frequency ratio for the five spatial resolutions. The results of the analysis were verified using the landslide location data and area under success rate curve. The spatial resolutions of 5, 10 and 30 m showed similar results (the normalized area values 0.97, 1.00 and 0.92, respectively), but the 100 and 200 m spatial resolutions showed less well-verified data (the normalized area values 0.48, and 0.00, respectively). Because the scale of the input data was 1∶5,000–1∶50,000, the 5, 10 and 30 m spatial resolutions had a similar accuracy, but the 100 and 200 m spatial resolutions had a lower accuracy. From this, we conclude that spatial resolution has an effect on the accuracy of landslide susceptibility, as it is dependent on the input map. At least, less than 30 m resolution is need for landslide analysis in Korea where most of map scale is in the range 1∶5,000–1∶50,000.