Characteristics of ring tectonic landforms in Yunnan’s Lufeng Dinosaur Valley based on ALOS DEM

Based on ALOS DEM data and GF-2 satellite images, the topographic features of the annular structures in Yunnan Province were quantitatively explored by extracting the topographic features through modern remote sensing mapping technology and GIS tools. The results showed that: ① The optimal analysis window of topographic relief in the study area is 16×16 (0.04 km²). ② By using correlation analysis, it is found out that optimal is the combination of such terrain factors as slope, aspect, topographic relief and surface roughness. ③ The study area presents obvious characteristics of double ring ridgelines and the valley line, and the distribution of the ring area is radioactive. The valley water system network demonstrates a dendritic pattern, dense in the north and sparse in the south. ④ Gentle slopes (42.372%) and steep slopes (37.589%) are the main slopes in the study area, with obvious slope-degree changes and complex slope-orientation distributions. The overall topography of the study area is hilly, gradually rising from the center to the ridgelines, and contains a number of undulating hills with some craters among them. The area of the ring between the ridgelines and the valley line is a longitudinally distributed ridge valley with steep slopes and deep gullies.