董卫华团队参加江苏卫视《最强大脑》节目录制

地理科学学部董卫华老师作为特约嘉宾参加江苏卫视《最强大脑》第四季节目录制,该节目已于2017年1月13日在江苏卫视播出,题目为《一眼辨山》。在节目中,选手通过观察三张随机选取的庐山3D实景图,在庐山全貌等高线地形图中绘制相应的观察点和观察方向,选手答案与正确答案相差在四度以内,点位偏差在两百米以内则回答正确,正确两题则挑战成功。为录制该节目,董卫华老师带队进行了为期半年的研究,并亲赴庐山进行实地考察。以下为该节目的视频:

Selection of LiDAR geometric features with adaptive neighborhood size for urban land cover classification

Abstract: LiDAR has been an effective technology for acquiring urban land cover data in recent decades. Previous studies indicate that geometric features have a strong impact on land cover classification. Here, we analyzed an urban LiDAR dataset to explore the optimal feature subset from 25 geometric features incorporating 25 scales under 6 definitions for urban land cover classification. We performed a feature selection strategy to remove irrelevant or redundant features based on the correlation coefficient between features and classification accuracy of each features. The neighborhood scales were divided into small (0.5–1.5 m), medium (1.5–6 m) and large (>6 m) scale. Combining features with lower correlation coefficient and better classification performance would improve classification accuracy. The feature depicting homogeneity or heterogeneity of points would be calculated at a small scale, and the features to smooth points at a medium scale and the features of height different at large scale. As to the neighborhood definition, cuboid and cylinder were recommended. This study can guide the selection of optimal geometric features with adaptive neighborhood scale for urban land cover classification.

Cite this paper: Dong, W., Lan, J., Liang, S., Yao, W. and Zhan, Z. 2017. Selection of LiDAR geometric features with adaptive neighborhood size for urban land cover classification. International Journal of Applied Earth Observation and Geoinformation, 60, 99-110. DOI: 10.1016/j.jag.2017.04.003