Vol.9 No.2 2016

Research paper : Three-dimensional urban geological map (T. NAKAZAWA et al.)−83−Synthesiology - English edition Vol.9 No.2 (2016) Using this algorithm, a temporary 3D geological model was created based on the standard borehole data of 14 points, outcrop logs at 355 points, and landform classification maps. We created the prototype of the 3D geological map that allows browsing of maps, arbitrary cross-section diagrams, 3D models, and borehole data using the aforementioned browsing system (Fig. 6).[30] We are aiming ultimately for geological maps that can be used at 1:25,000 scale that surpasses the basic scale (1:50,000) of the geological maps, by raising the precision of the geological model by increasing the standard borehole data to 20 points or more and using about 20,000 existing borehole data. Through such organization of the geological maps, it is expected that geological disaster risk evaluation will become possible at higher precision.6 ConclusionFor the 3D geological map that is being attempted presently in the testing area, standard borehole data will be added in the future, and correlation of strata for the existing borehole data will be furthered to enhance the precision of the 3D geological model. The cross-section diagrams and 3D models will be revised for better operation and usability, and it is scheduled for disclosure in FY 2017. This result will be proposed as a new style of geoinformation for urban areas, and we hope this will initiate the expansion to other cities through the cooperation of the local governments. A guideline is considered that allows the local governments to create their own geological maps, and technical support will be provided where needed. By promoting the organization of geoinformation that is easy to understand, easy to use, and highly reliable for the urban areas, we hope the utilization of the geoinformation by the administration, companies, and general public will be further promoted.AcknowledgementsIn pursuing this research topic, we held various discussions to determine the direction of research with the following people from the start of the project: Measurement and Intellectual Infrastructure Division, METI; Research Planning Office for Geological Survey and Applied Geoscience (currently, Research Planning Office for Geological Survey of Japan), AIST; Geoinformation Center (currently, Geoinformation Service Center), AIST; executive personnel of the Research Institute of Geology and Geoinformation; Junko Komatsubara, Tomonori Naya, Ikuo Cho, and Kentaro Sakata of the Research Institute of Geology and Geoinformation who participated in this research topic; and the people of the Geological Environment Laboratory, Chiba Prefectural Environmental Research Center. We are grateful to all those involved.TerminologiesTerm 1.Secondary use: According to the “Guide for the promotion of disclosure and secondary use of ground information” (June 2013) of the Ministry of Internal Affairs and Communications, secondary use of ground information is defined as “the use or provision of ground information (such as borehole data) supplied by administrative organizations and others, by forming them into information that can be easily used or by adding other information.” Primary use is defined as “the use by the administrative institutions and others that possess the ground information mainly for their internal use.” In the open government data strategy, it is written that “the public data possessed by the Government, independent administrative bodies, local governments, or others should be disclosed in the machine readable data format, and should be subject to rules that allow secondary use including for commercial purposes.”Term 2.Stratigraphy: A discipline that clarifies the layering order of the strata from fossils, measured age, and strata characteristics.Term 3.Sedimentology: A discipline that clarifies the process and mechanism by which the sedimentary layers are formed from the properties of the deposits.Term 4.Spline: A piecewise polynomial function in which the target region is broken down into multiple segments and the polynomial equation is set for each segment. It is excellent for fitting curves and curved surfaces with complex shapes.Term 5.RDBMS (relational database management system): A general term for the software for managing relational databases. In RDBMS, comparison, joining, extraction, and others of the data are done while the data are managed in a table format.Term 6.PostgreSQL: Open source RBDMS that can be used for various purposes, free of fee, license, secondary distribution, and others. SQL is used for database operation.References[1]K. Wakamatsu and S. Senna: Tohoku Chiho Taiheiyo-oki Jishin (Higashi Nihon Dai Shinsai) ni yoru ekijoka to kako no ekijoka rireki [Liquefaction in the 2011 Off the Pacific Coast of Tohoku Earthquake (Great East Japan Earthquake) and past history of liquefaction], Chishitsu To Chosa, 2013


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