This article aims at dealing with the inconveniences—associated with places—the foreign tourists are experiencing by utilizing the big data technology. It analyzes the spatial density of floating population of foreign tourists and suggests a variety of applications based on the results. This thesis associates the roaming big data of foreign tourists with Geographic Information System(GIS) to analyze the floating population density by location, time, and country. It uses R-Studio, a statistical computing software, and QGIS, an open source GIS software to visualize the data on a map. The first step to conduct the research is to open CSV format data and set variables for analysis. Then it analyzes the spatial density of floating population of foreign tourists sorted by time, location, and country, and the number of visitors is ranked for each location. Based on the analysis results, the data are visualized on a map through QGIS. Lastly, several adjacent target points—base stations—for certain locations are matched, and the necessary data are sampled out of them. This paper selects fourteen locations whose floating population of foreign tourists is dense: Gyeongbok Palace, Namsan Hanok Village, Deoksu Palace, Insadong, Myeongdong, Namdaemun Market, Dongdaemun Market, Garosu-gil, Apgujeongdong, Itaewon, Hongik University Entrance, Gangnam Station, COEX, and Lotte World. Moreover, it categorizes fourteen places into historical, shopping, and complex attraction and delves into the pattern or characteristics of floating population according to the categories; the categorized results directly show the distinct preferences for places and visiting time period. (Although the names of the countries the tourists are from are not provided in the roaming data of foreign tourists, they could be readily inferred from the comparison of the analysis results to the survey conducted by Korea Chamber of Commerce and Industry.) This research paper makes four pragmatic proposals in order to alleviate the inconveniences regarding the signposts, bus route, and insufficient tourist information centers; it suggests to add languages in the signposts for certain locations, modify the current route of the city tour bus, and build additional tourist information centers in several sites where floating population of foreign tourists turns out to be dense. The degree of correspondence between the analysis results and reality is examined via field inspection. Recently, tremendous amount of data is produced and open to public, which leads to the enhancement of transparency. This article, which connects the big data to GIS technology, would be one of the significant cases of effectual spatial decision.