标题：Qualitative direction relation reasoning in 3-dimensional GIS
作者：Liu, Xin ;Liu, Wen-Bao ;Cui, Xian-Guo
作者机构： College of Geo-information Science and Engineering, Shandong University of Science and Technology, Qingdao 266510, China
来源：Liaoning Gongcheng Jishu Daxue Xuebao (Ziran Kexue Ban)/Journal of Liaoning Technical University (Natural Science Edition)
摘要：The spatial relation is described with the direction relation in GIS. The 27 × 27 = 729 qualitative reasoning results of 27-direction system can be got in 3D space. Laws of qualitative direction relation reasoning between direction relations are the improvement of studying qualitative seasoning between single direction relations. Using simplicial data model, some laws in qualitative direction relation reasoning are studied based on projection 27 direction relation system in the paper. Some important results are given in the end.