• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.434-437
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• 2007

Maps contain and effectively visualize a number of spatial information. Advances in GIS enable researchers to analyze and represent spatial information through digital maps. Choropleth maps represent different quantities showing usually rates, percentages or densities. Generally, researchers make choropleth maps using raw rates. But, if the events are rare, raw rates cannot be sufficient in representing spatial phenomena. That is to say, if the population is large and events are rare, we cannot be sure that the raw rate is correct. The objective of this study is to make choropleth maps by several rate calculation methods and compare them. We use three methods in choropleth mapping; a raw rate, empirical Bayesian method, and spatial rate method which use prior probabilities. The experiments reveal that maps are somewhat different by used methods. We suggest that a raw rate method can not be an only way to make a rate map and researchers should choose an appropriate method for their objectives.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.6
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• pp.571-580
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• 2014

To address unsolved issues of change detection in animated choropleth maps, we proposed the concept of 'gross change detection' and performed an experiment that empirically verifies the incidence of change blindness stems from the 'magnitude of change (MOC)', spatial distribution in animated choropleth maps. We generated experimental materials using the change-characterization arrays and the global Moran's I. Participants had 108 cases of changing maps with time duration (1 to 3 sec) and had questions. The results showed that MOC and duration affect gross change detection, but the most interesting result from our experiment was that different spatial distributions between two adjacent choropleth maps may lead the map reader to under- or over-estimate the level of gross change in the map. It implies that we should consider spatial distribution of change when we design animated choropleth maps.

• Spatial Information Research
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• v.2 no.2
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• pp.107-116
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• 1994

Choropleth map is a type of thematic maps in which areal units are shaded with a color or pattern that symbolizes some characteristic of the mapped unit. CMS was first developed to produce choropleth maps on ordinary microcomputer environments in 1988. Since then there have been significant technological developments and enhancements in user environments, which have affected the field of choropleth mapping systems posi¬tively. A new version of CMS was developed in accordance with these changes. CMS II requires an IBM PC, or compatible, with the minimum 640KB memory and VGA graphic board. It supports HP laser jet printers to output a high resolution map. The program can use Hangul letters for main menu, map title, and legend. And dBase file format (DEW) was implemented to exchange attribute files effectively.

• Journal of Preventive Veterinary Medicine
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• v.41 no.2
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• pp.79-83
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• 2017

In this study, we used a choropleth map to explore the spatial variation of the risk of cattle herds being bovine tuberculosis (BTB) positive in Gangwon-do in 2015. The map shows that the risk of being BTB-positive was lower in provinces located in the middle of Gangwon-do (Wonju, Youngwol, Peongchang, and Kangneung) than in other provinces. In addition, one province located in the north (Goseong) had a low risk of BTB. The estimate for the intercept of the spatial lag model was 0.66, and the spatial autocorrelation coefficient (lambda) was 0.20 (Table 1). The Moran's I was 0.33 with p-value of 0.02. In 2015, provinces located in the North West (Hwacheon) and East (Donghae) of Gangwon-do had a higher BTB risk. We identified some specific provinces at low BTB-positive risk, information that may prove useful for control of BTB in the study area.

• Journal of the Korean Geographical Society
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• v.36 no.4
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• pp.434-443
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• 2001

Differing from the existing method to optimize the statistical proximity, the new optimization method was developed to maximize the spatial proximity among the unit areas of choropleth map. 25 choropleth maps were made using 5 classification methods(maximum BEI, maximum TEI, equal interval, natural break, n-tile) for 5 classes(3∼7) and were analyzed to elucidate the effectiveness of classification methods on the basis of 3 evaluation indeces (TEI, BEI, $C_{F}$). The results from the maximum TEI and maximum BEI were evaluated as relatively stable and effective compared to those from other classification methods. But they showed the opposite trends owing to the trade-off relationships. Meanwhile, the resets from the natural break method got higher marks, which was also identified through the analysis using a new $alpha$-index.x.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.1
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• pp.107-117
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• 2011

This study aimed to inquire into possibilities of the web-based representation of thematic maps by geo-information mashup in the geoweb platform. In the Web2.0, Google platform leads the geoweb by offering effective mashup functions for geo-information. Geo-information mashup is opening a new horizon of map applications in fusion with a great of data in the Internet. Geo-information mashup by the available data method can be classified as two type; one is linkage of sources of platform itself(satellite images) and external data, the other is linkage of platform itself and user created contents. This study made heatmap, proportional map, and choropleth map based on Google satellite images by the linkage of platform itself and external data. As a result, thematic map of Google mashup expected to give us to a flexibility for difference interpretations of geographical distribution by representing overlap with satellite images.

• Journal of the Korean Geographical Society
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• v.46 no.1
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• pp.67-80
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• 2011

Choropleth mapping of population distribution is based on the assumption that people are uniformly distributed throughout each enumeration unit. Dasymetric mapping technique improves choropleth mapping by refining spatially aggregated data with residential information. Further, pycnophylactic interpolation can upgrade dasymetric mapping by considering population distribution of neighboring areas, while preserving the volumes of original units. This study proposed a combined solution of dasymetric mapping and pycnophylactic interpolation to improve the accuracy of population density distribution. Specifically, the dasymetric method accounts for the spatial distribution of population within each census unit, while pycnophylactic interpolation considers population distribution of neighboring area. This technique is demonstrated with 1990 census data of the Athens, GA. with land use land cover information derived from remotely-sensed imagery for the areal extent of populated areas. The results are evaluated by comparison between original population counts of smaller census units (census block groups) and population counts of the grid map built from larger units (census tracts) aggregated to the same areal units. The estimated populations indicate a satisfactory level of accuracy. Population distribution acquired by the suggested method can be re-aggregated to any type of geographic boundaries such as electoral boundaries, school districts, and even watershed for a variety of applications.

• Spatial Information Research
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• v.12 no.2
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• pp.165-179
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• 2004

With the spread of wireless internet, the interest in mobile applications and services is increasing. Korea Wireless Internet Standardization Forum has been establishing the standards for mobile platform and map service in the wireless internet environment. This study aims to present a paragon of mapping middleware that plays the role of broker for wireless internet map service: in particular, it focuses on the interoperability with generic map servers. In this study, we developed a method for applying current map servers to the wireless internet map service, and analyzed the request/response structure of the map servers which have different operation characteristics in order to allow our middleware to fully utilize the functionalities of the map servers. The middleware we developed is composed of .NET-based XML Web Services: it has a lightweight module for image map and a map representation module for choropleth map, symbol map, chart map, etc. This mapping middleware is a broker between mobile client and generic map server, and supports .NET clients and Java clients as well. Its component-based interoperability grants the extensibility for the wireless internet dedicated map servers of the future in addition to the current generic map servers.

• Spatial Information Research
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• v.18 no.4
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• pp.141-149
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• 2010

One of recent trends in Web-based GIS is the system development using FOSS (Free and Open Source Software). Open Source software is independent from the technologies of commercial software and can increase the reusability and extensibility of existing systems. In this study, we developed a Web-based GIS for interactive visualization of geographic information using Google Earth and spatial DBMS(database management system). Google Earth Plug-in and Google Earth API(application programming interface) were used to embed a geo-browser in the Web browser. In order to integrate the Google Earth with a spatial DBMS, we implemented a KML(Keyhole Markup Language) generator for transmitting server-side data according to user's query and converting the data to a variety of KML for geovisualization on the Web. Our prototype system was tested using time-series of LAI(leaf area index), forest map, and crop yield statistics. The demonstration included the geovisualization of raster and vector data in the form of an animated map and a 3-D choropleth map. We anticipate our KML generator and system framework will be extended to a more comprehensive geospatial analysis system on the Web.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.149-151
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• 2018

The purpose of this paper is to visualize and to analyze differences of regional mortality rates by major causes of death. We use causes of death statistics from KOSIS and compare regional mortality rates divided by national mortality rates by three causes of death. To do this, we define regional mortality ratio and regional age-standardized mortality ratio, and visualized by choropleth map using R. As a result, In case of neoplasm, there was no significant difference by region. In case of circulatory system, Ulsan, Daegu, Busan and Gyungnam showed relatively high regional age-standardized mortality ratio. In case of respiratory system, the ratios were in order of Gangwon, Sejong, and Chungbuk.