From geographic information service to geographic knowledge service: research issues and development roadmap
SHEN Li, XU Zhu, LI Zhilin, LIU Wanzeng, CUI Bingliang
Acta Geodaetica et Cartographica Sinica . 2021, (9): 1194 -1202 .  DOI: 10.11947/j.AGCS.2021.20210183