Mangrove forest was once cut down on a large scale area to use for shrimp culture etc. But now, mangrove reforestation is advanced for the disaster prevention in the coastal area and for increase in production of marine resources. However, reforestation activities are not so going well. Although it is known that the ground level has affected the result of reforestation, the range of exact adaptation is not examined well. When a mangrove area is used for other purposes, the ground level is usually changed. In this paper, in order to estimate the suitable growth condition in Rhizophora apiculata, the relative height in the study area was measured by high precision GPS. Then, the biomass in the area as the index of productivity was calculated using the aerial-photograph taken by radiocontrolled helicopter. Fine satellite imagery is hard to be obtained in a tropical region, and the tidal level at the observation influences analysis for mangrove region. The radio controlled-helicopter can be applied at any time standing by. This is the reason why we used this platform. As a result of the analyzing optimum growth condition in Rhizophora apiculata based on the above-mentioned, it was found that the range of relative height suitable for growing is between 36cm and 95cm.
Although many camera calibration methods for a non-metric digital camera have been proposed, there are few reports on precision of calibration results. Therefore, we conducted a field experiment to examine precision of calibration results. We adopted a calibration method using a set of calibration points distributed on the 2-D plane. A round of camera calibration utilized a set of eight convergent images acquired from eight different directions with four different camera frame rotation angles of 0°, +90°, +180° and -90° around the optical axis of the camera. 32 rounds of camera calibration for each camera were conducted. Moreover, a numerical simulation of 3-D measurement using the obtained image distortion model was carried out to investigate the influence of the difference between the obtained image distortion models. Experimental results indicated that dispersions of image distortions between obtained image distortion models cannot be neglected. Difference of image distortions may make more than twenty times larger errors at 3-D measurement without an exterior orientation. The most part of the difference between estimated image distortions was the difference of the estimated position of the principal point, while the differences of another components of the image distortion model were small enough to be negligible.
Global land cover data are necessary for global environmental monitoring and research studies. To classify land cover in Asia, first, ground truth (GT) data were collected as the training data. In the authors' previous study paddy in south China were misclassified into evergreen broadleaf and needleleaf forests, because paddy GT data were not collected in south China but in Japan. In this study, paddy GT data in China were newly collected from 1-km-grid China land use data, which were prepared by Chinese Academy of Science. Next, maximum likelihood method was applied to monthly Normarized Difference Vegetation Index (NDVI) data, which were calculated from 1-km-grid Systèm Pour 1'Observation de la Terre (SPOT) /VEGETATION data in 2000. Finally, land cover was classified into 19 items and it was found that paddy was correctly classified in south China (correct ratio : 100% on GT sites) .
This paper describes the analysis to investigate the characteristics of high resolution satellite imagery about forest species to develop a forest species discrimination method. The study was carried out for the mountain area located in the Yamato and Minami district, Gifu Prefecture, in Japan.Eight kinds of forest species, the Japanese cedar, the hinoki cypress, the Japanese red pine, the pine death area, the Japanese larch, the oak, the chestnut and the bamboo which are distributed in the area, are investigated in this study. The reflection characteristic and the texture characteristic of IKONOS pansharpen data for the eight test sites concerning the eight forest species are analyzed by using the forest type map based on the field survey.The area size of the test sites are 200m square and the size of the filter for the texture analysis is 7 pixel square.It was made clear by the analyses that the Japanese cedar and the bamboo have specific distributions on histogram of DN for ch.4 of IKONOS data and that the Japanese cedar, the hinoki cypress and the Japanese red pine have different distributions on histogram of the mean values of DN within the filter.It was also noticed by the application of the results for the discrimination for the forest species in the test sites that the results of a spectrum analysis and a texture analysis are effective for extraction of the target forest species in the test sites, especially for the Japanese cedar, the hinoki cypress, the Japanese larch and the bamboo.