Vol.1 No.2 2008

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Research paper : Creation of seamless geological map of Japan at the scale of 1:200,000 and its distribution through the web (K. Wakita et al.)−80 Synthesiology - English edition Vol.1 No.2 (2008) Map of Japan provided on the web will be 3 m x 7 m if printed in scale. Almost 4 gigabyte file size is necessary to provide image that is clear enough to be enlarged on screen (400 dpi). Since this data size is too large for users to download at once, it became crucial for us to develop a transmission system to instantaneously deliver required data to where they were needed. Although several software for this purpose were already available commercially, we decided to develop our own program, J-GeoView, to reduce cost and to optimize representational function. It enabled continuous zooming in/out and displayed geological explanation at the position of the cursor. Along with academic description, we provided plain and simple explanations without complex technical terms for general users.5 Further development of seamless geological map and challenges for the future5.1 Refinement of geological information and integrating technologyThe seamless geological map was created without conducting field surveys. However, field surveys and mapping are essential to improve the accuracy of geological maps and to update the geological information such as distribution of rocks, faults, and other geological features. To accomplish this task, we must collaborate with specific research groups who are in charge of making geological maps at 1:200,000 and 1:50,000 scales. We are planning to revise the already published 1:200,000 geological maps in order of their publication date in the second business term of AIST (April 2005 ~ March 2010), and compile new maps in the third term or later (from April 2010). The above plans will significantly improve the contents of the seamless geological map.Data in the seamless geological map are delivered in vector format by GeoMapDB developed in 2006 at http://iggisl.muse.aist.go.jp/ja/top.htm. One of the features of vector format is that it can separately manage corresponding data by cutting each element that composes the ground surface based on object-oriented concept. It allows continuous zooming in/out and arbitrary change of color and size. It also enables addition of attributes for rocks or faults such as age, thickness, and lithofacies. The method adopted in seam-smoothing geological map fully exploits the above features. In the future, strict standardization of data and development of data model to standardize the structures among data sets will lead to deployment of the maps as spatial relational database, and consequently will result in convenient usage including flexible search, analysis, drawing, simulation, and automatic control[12].Combination of these features will enable us not only to use the seamless map as a planimetric map, but also allows us to draw geological profile and multi-dimensional map, and create geologic time scale using a single set of data in the seamless geological map. We have started normalization and standardization of geological data, data model establishment, and development of the data to achieve these goals.5.2 Seamless geological map as an information infrastructureThe seamless map aims not only for greater convenience and broader delivery via the Internet, but also aims to make geological maps shared and widely used in society as a common national property. We shall continue our efforts in making the map available to everyone through the Internet.One example is the mutual use of data between engineering geological map and surface geological map of the Ministry of Land, Infrastructure, Transportation and Tourism (MLIT) and seamless geological map of the AIST, and this is making major contribution to the reciprocal exchange of the latest geological map information (Figure 9), as well as to cost reduction. Actually, engineering geological map[13] was used as reference in the compilation of the seamless map of Shikoku region. On the other hand, vector data of the seamless geological map were used to create the engineering geological map of Tohoku region[14]. Interoperation between other geospatial information is another important aim of the seamless geological map. We are currently promoting joint researches in environmental field with Nagoya University, Tohoku University, and others. Within AIST, the seamless geological map is utilized as basic geological information in the study of active faults and soil contamination.Creation of the 1:200,000 Seamless Geological Map of Japan triggered the research project called “Basic Research on Development of a Highly Information-Interoperable Database for Integrated Geoscience Atlas” in which other Fig. 8 Homepage of the Seamless Geological Map of Japan 1:200,000.(8)−

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