Digital Map 50m Grid (Elevation) provided by Geographical Survey Institute (GSI) is very useful for users to prepare the data set suitable for their purposes. However, the altitude accuracy is verified only in the limited narrow region. This research estimates the accuracies of the 50m DEM data set using 965 triangulation points in the entire Japan. It is found that the mean range of altitude is 6.2m, the standard deviation is 6.2m and the root mean square error is 8.8m.

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The Seamless Digital Geological Map of Japan (1:200,000) (SDGMJ) is a geological map covering the entire area of Japan with a unified legend. SDGMJ is available via Web Map Tile Service (WMTS) that is one of the standard services implemented by the Open Geospatial Consortium. However, WMTS for SDGMJ has not been in widespread use because WMTS is a relatively new standard service. The purpose of this study is to create better conditions for promoting utilization of geological information. In this paper, we described a usage of WMTS for SDGMJ using Free and Open Source Software for Geoinformatics (FOSS4G): GDAL Utility Programs (GDAL UPs), Quantum GIS (QGIS), Leaflet, and OpenLayers. In addition, focusing on purpose of use of WMTS for SDGMJ, we summarized characteristics of each FOSS4G: GDAL UPs is suitable for getting SDGMJ within multiple areas with arbitrary zoom level. QGIS is suitable for overlay SDGMJ on various geospatial information, which are stored in one's PC or are distributed from other Web services. Leaflet and OpenLayers are suitable not only for constructing Web sites that display SDGMJ with other geospatial data but also for searching a legend of SDGMJ at arbitrary points. In conclusion, FOSS4G enables us to use WMTS for SDGMJ without any concern for fee and restriction on the use. Furthermore, combined use of several FOSS4G enable integrated analyses using geological information in conjunction with other geospatial information.

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