Journal of Geography 116 (6) 749-758 2007 Configuration of Rapid Digital Mapping System Using Tablet PC and its Application to Obtaining Ground Truth Data: A Case Study of a Snow Survey in Chuetsu District, Niigata Prefecture Yuichi SHIMAMURA*, Takeki IZUMI** and Hiroshi MATSUYAMA** Abstract In this study, a rapid digital mapping system was developed using a tablet PC. Usually, digital maps are more compact and handy than hard-copy maps. GPS receivers are convenient devices for real-time positioning in outdoor fields. A digital pen provides the useful interface for a tablet PC. GIS application (ESRI ArcGIS) can enlink these devices and technologies. The distributions of snow-covered and forested areas were visually confirmed from a moving vehicle, and were input into digital maps through a tablet PC. In this system, the GPS receiver displays the current location on the digital maps. The digital maps are seamless, and can be scrolled automatically incorporating information from the GPS receiver. This mapping system, therefore, can obtain and record ground truth data quickly at a speed comparable to that of a moving vehicle, even if the operator does not have any experience of computer mapping. In comparison with mapping using hard-copy maps, 60% of the time necessary for in situ mapping is saved using this system. On the other hand, only 20% of the time necessary for editing the map is saved, due to the difficulty of making a clean copy of an in situ map. In conclusion, 30% of the total time for obtaining ground truth data is saved using this mapping system, which certainly contributes to field surveys in general. Key words ground truth data, tablet PC, GPS, digital map, GIS, snow survey * Department of Geography ** Department of Geography, Graduate School of Science, Tokyo Metropolitan University, Graduate School of Urban Environmental Sciences, Tokyo Metronolitan University
Fig. 1 Configuration of mapping system.
Table 1 Main specification of HP TC1100.
Fig. 2 In situ mapping. Mapping with tablet PC. (b) and (c) Mapping with hard-copy maps and laptop computer.
Table 2 Price of each device used to configure the mapping system.
Fig. 3 Study area for getting ground truth data.
(b) 図 4 Fig. 4 タ ブ レ ッ トPCに 入 力 さ れ た 地 表 面 状 態. 現 場 に お い て 情 報 が 書 き 込 ま れ た 状 態. Information Ground surface condition input obtained by in situ field survey. (b) を on tablet 清 書 し た も の. PC. (b) Clean copy of. (a: グ ラ ン ドトゥル ー ス) (b) (b: 衛 星 に よる推 定) 図 5 グ ラ ン ド トゥ ル ー ス と衛 星 画 像 の 重 ね 合 わ せ グ ラ ン ド ト ゥ ル ー ス に よ り得 ら れ た 積 雪 分 布 図. Fig. 5 Overlapping Snow distribution map obtained overlaid on. (b) (2006年3月28日). 衛 星 に よる積雪 分布 図 を に 重 ね 合 わ せ た も の. ground truth data and satellite image (28th March, 2006). by in situ mapping. (b) Snow distribution map estimated by satellite 755 data
Table 3 Time necessary for getting ground truth data of an area corresponding to four 1: 25,000 maps.
Shimamura, Y., Izumi, T. and Matsuyama, H. (2006) : Evaluation of a useful method to identify snow-covered areas under vegetation \Comparisons among a newly-proposed snow index, normalized difference snow index, and visible reflectance. Int. J. Remote Sens., 27, 4867-4884.