{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,4]],"date-time":"2025-11-04T23:32:38Z","timestamp":1762299158273,"version":"build-2065373602"},"reference-count":36,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2019,12,3]],"date-time":"2019-12-03T00:00:00Z","timestamp":1575331200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the Open Project Program of the State Key Laboratory of Virtual Reality Technology and Systems, Beihang University","award":["01119220010011"],"award-info":[{"award-number":["01119220010011"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJGI"],"abstract":"<jats:p>Urban areas involve different functions that attract individuals and fit personal needs. Understanding the distribution and combination of these functions in a specific district is significant for urban development in cities. Many researchers have already studied the methods of identifying the dominant functions in a district. However, the degree of collection and the representativeness of a function in a district are controlled not only by its number in the district but also by the number outside this district and a number of other functions. Thus, this study proposed a quantitative method to identify urban functions, using Fisher\u2019s exact test and point of interest (POI) data, applied in determining the urban districts within the Sixth Ring Road in Beijing. To begin with, we defined a functional score based on three statistical features: the p-value, odds-ratio, and the frequency of each POI tag. The p-value and odds-ratio resulted from a statistical significance test, the Fisher\u2019s exact test. Next, we ran a k-modes clustering algorithm to classify all urban districts in accordance with the score of each function and their combination in one district, and then we detected four different groups, namely, Work and Tourism Mixed-developed district, Mixed-developed Residential district, Developing Greenland district, and Mixed Recreation district. Compared with the other identifying methods, our method had good performance in identifying functions, except for transportation. In addition, the Coincidence Degree was used to evaluate the accuracy of classification. In our study, the total accuracy of identifying urban districts was 83.7%. Overall, the proposed identifying method provides an additional method to the various methods used to identify functions. Additionally, analyzing urban spatial structure can be simpler, which has certain theoretical and practical value for urban geospatial planning.<\/jats:p>","DOI":"10.3390\/ijgi8120555","type":"journal-article","created":{"date-parts":[[2019,12,4]],"date-time":"2019-12-04T04:30:35Z","timestamp":1575433835000},"page":"555","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["Quantitative Identification of Urban Functions with Fishers\u2019 Exact Test and POI Data Applied in Classifying Urban Districts: A Case Study within the Sixth Ring Road in Beijing"],"prefix":"10.3390","volume":"8","author":[{"given":"Disheng","family":"Yi","sequence":"first","affiliation":[{"name":"College of Resources Environment and Tourism, Capital Normal University, Beijing 100048, China"},{"name":"2D Information Collection and Application Key Lab of Education Ministry, Capital Normal University, Beijing 100048, China"},{"name":"Beijing State Key Laboratory Incubation Base of Urban Environmental Processes and Digital Simulation, Capital Normal University, Beijing 100048, China"}]},{"given":"Jing","family":"Yang","sequence":"additional","affiliation":[{"name":"College of Resources Environment and Tourism, Capital Normal University, Beijing 100048, China"},{"name":"2D Information Collection and Application Key Lab of Education Ministry, Capital Normal University, Beijing 100048, China"},{"name":"Beijing State Key Laboratory Incubation Base of Urban Environmental Processes and Digital Simulation, Capital Normal University, Beijing 100048, China"}]},{"given":"Jingjing","family":"Liu","sequence":"additional","affiliation":[{"name":"College of Resources Environment and Tourism, Capital Normal University, Beijing 100048, China"},{"name":"2D Information Collection and Application Key Lab of Education Ministry, Capital Normal University, Beijing 100048, China"},{"name":"Beijing State Key Laboratory Incubation Base of Urban Environmental Processes and Digital Simulation, Capital Normal University, Beijing 100048, China"}]},{"given":"Yusi","family":"Liu","sequence":"additional","affiliation":[{"name":"College of Resources Environment and Tourism, Capital Normal University, Beijing 100048, China"},{"name":"2D Information Collection and Application Key Lab of Education Ministry, Capital Normal University, Beijing 100048, China"},{"name":"Beijing State Key Laboratory Incubation Base of Urban Environmental Processes and Digital Simulation, Capital Normal University, Beijing 100048, China"}]},{"given":"Jing","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Resources Environment and Tourism, Capital Normal University, Beijing 100048, China"},{"name":"2D Information Collection and Application Key Lab of Education Ministry, Capital Normal University, Beijing 100048, China"},{"name":"Beijing State Key Laboratory Incubation Base of Urban Environmental Processes and Digital Simulation, Capital Normal University, Beijing 100048, China"}]}],"member":"1968","published-online":{"date-parts":[[2019,12,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"446","DOI":"10.1111\/tgis.12289","article-title":"Extracting urban functional regions from points of interest and human activities on location-based social networks","volume":"21","author":"Gao","year":"2017","journal-title":"Trans. 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