Bulletin of the GSI (Vol.62)
Toru NAGAYAMA, Yoshihisa SERIZAWA
The Geospatial Information Authority of Japan (GSI) established its Long-Term Plan for Basic Survey and the GSI Research and Development Basic Plan in April 2014. The LT Plan gives the objectives of basic surveys and the measures of GSI to achieve these objectives. Meanwhile, the RD Plan gives the direction for research and development implemented by GSI. Based on these strategic plans, GSI applies itself on its work. This article presents the highlights of these two important plans toward the realization of geospatially enabled society in Japan.
2. Long-Term Plan for Basic Survey
2.1 Background of establishment
2.2 Highlights of the LT Plan
3. GSI Research and Development Plan
3.1 Background of establishment
3.2 Highlights of the RD Plan
Basara MIYAHARA, Tokuro KODAMA, Yuki KUROISHI
We have developed a new hybrid geoid model of Japan, “GSIGEO2011”, which was made publicly available on April 1, 2014. The model was created in such a way that a high-resolution gravimetric geoid model for Japan, “JGEOID2008” was fitted to GNSS/leveling geoid undulations at 971 sites by the Least-Squares Collocation method. The model reproduces geoid heights at the GNSS/leveling sites with the consistency of a standard deviation of 1.8 cm. By utilizing the model to convert GNSS-derived three-dimensional positions to orthometric heights, GNSS survey can determine orthometric heights at the same precision as third-order leveling surveys. Orthometric height determination by GNSS surveying has been applicable in public surveys as alternative to third-order leveling in Japan since April 1 2014.
2. Strategy of Model Development
3. GNSS/leveling Derived Geoid Undulation Data
4. Development of Hybrid Geoid Model, GSIGEO2011
4.1 Geoid Model for the Western Part of Japan
4.2 Geoid Model for Eastern Part of Japan
4.3 Internal Consistency of the Final Geoid Model
Noriyuki TAKAKUWA, Shoichi OKI, Hidenori FUJIMURA, Ritsu OKAYASU, and Takenori SATO
The GSI uses contour maps to express topography on planar maps, but users need a certain ability to read and understand the topography. Therefore, the GSI developed the GSI Maps 3D that enables users to view any area in Japan in 3D on an Internet browser and to create the data for 3D printers, so that anyone can intuitively understand topography.
The GSI Maps 3D site acquires elevation tiles delivered from the GSI Maps web server for the surrounding area which the user selects, and create a 3D model using a technology called WebGL. Then, the site displays 3D map by attaching corresponding topographical map or aerial photo images to the ground surface. This 3D processing utilizes the latest Internet technologies such as WebGL and HTML5 Canvas, and various technical issues associated with these technologies have been addressed. Regarding functions that are output as data for 3D printers, the GSI received advice from outside experts on such things as file formats.
Future plans call for such public infrastructure as dams and bridges to be displayed in GSI Maps 3D and to improve functions for managing it.
3. Basic elements and processing flow of 3D CG
4. Use of GSI tiles
4.1 Restrictions on image processing when using Canvas
5. Provision of data for 3D printers
6. Concluding remarks
Yudai SATO, Hiroki MURAMATSU, Kenichi OSHIMA, Takaaki INUKAI
Okinotorishima Island is the southernmost island of Japan, located on the Philippine Sea plate. On the island, Geospatial Information Authority of Japan (GSI) set triangulation points and a GPS continuous observation station in 1989 and 2005, respectively, and has conducted GPS surveys since 1992 for surveying and crustal deformation monitoring. This report describes the displacement of Okinotorishima Island from 2005 to 2013 as a result of re-analyzing GPS data using GAMIT software. The displacement suggests that Okinotorishima Island has moved WNW at Vns = +21.6 mm/year and Vew = -58.0 mm/year, or moved N66.8°W at 61.9 mm/year. The rate of collection of data at the island is lower than that of the GSI’s other GNSS stations because the station is an extremely isolated island in the Pacific Ocean. In order to monitor the movement of Philippine Sea plate, it is necessary to continue the maintenance of observation devices and enhance the station’s data availability.
2. Okinotorishima Island and control points
3. Data and Analysis
4. Result and Discussion
5. Maintenance of control points for stable GNSS data collection