Airborne laser scanning has become an established tool for generating digital terrain model (DTM) . To obtain DTM in the vegetative area, laser-reflected points on the canopies should be filtered out from digital surface model (DSM) . The filtering is automatically and manually performed, but it is difficult to obtain the perfect DTM, especially in the vegetative hills or mountain areas. In this study accuracy of the“DTM”, which was obtained in the winter of December 2001 and 2002, is validated with ground control points, surveyed by traversing. As a result, root mean square errors (RMSE) are about 0.15m and 0.4-0.6m in the bare flat areas and vegetative slope areas, respectively. Moreover, penetration ratio which is defined by the number of reflected points in DSM divided by the number in DTM, was examined with the RMSE. It was found that the more the penetration ratio increases, the smaller the RMSE is.
This paper proposes vertical search stereo matching for 3-D conversion of building polygons in existing 2-D digital maps. This stereo matching is considered as a special type of vertical search locus method which uses a polygon as search window on a pair of stereo images. The 2-D coordinates of the polygon window is fixed to the known position in a 2-D map. The algorithm searches the elevation of polygon which gives the best fit between parts of stereo images within the areas where the polygon is projected. This method can be applied to 3-D conversion of building polygons in a 2-D digital map. Each searched elevation is expected to be the dominant elevation of the building roof. The experimental test shows that the precision of the vertical search is almost a height of 1 floor level and enough for city modeling or map modification on a digital stereo plotter.
GLI (Global Imager) is an imaging instrument that had been flying on ADEOS-II, a satellite launched in December 2003 as a part of JAXA's Earth observing programme. Precise geometric correction is one of the most difficult and indispensable process in remote sensing data. In this study, firstly, radiometric and geometric correc-tions were applied to 229 scenes of GLI levellb data over the world. Secondly, accuracy of system geometric correction was evaluated with the coastal lines using template matching technique. As a result, the root mean square geometric error was found to be 435-485m which corresponds to 1.7 pixel size in 250m resolution. The error vectors in one scene have the random distribution both in direction and size and it was found that the qualitative instrumental errors was not found in the system geolocation information. The whole processing system is developed as a package software under multi-platform environment and is freely available via the FTP site (ftp: //webgli.iis.u-tokyo.ac.jp/pub/gligeo/) .
This paper will focus on the administration or management of remote sensing data with the web based network communication. Though it is one of the important aspects to carry on esearch activities or encourage knowledge sharing, there is no adequate software to handle the remote sensing data in terms of cost and benefit. In this study, a free software package is developed for web based management system of remote sensing data from Terra ASTER and its performance is evaluated by comparing with the same type of existing systems. The advantage of our system is that it is designed to work under UNIX system in conjunction with the free software attached with that operating system. Another strength is the point that this system can be easily applied for other data source management such as Landsat and JERS-1 by modifying the corresponding module. An easy to use interface and processing system is expected to promote the use of ASTER data. The full package with UNIX compatible binary format is freely available via the FTP (ftp: //webmodis.iis.u-tokyo.ac.jp/ASTER/) .