Large-scaled internal waves are active in the Sulu Sea, South of Philippine. In this paper, we had collected more than 400 of ERS-1/2 SAR images, obtained during 1996 and 2001, from web site of Centre for Remote Imaging, Sensing and Processing (CRISP), http://crisp.nus.edu.sg. First, we plotted the distribution map of the internal waves in the Sulu Sea. From this map, we study the generation, propagation and evolution of internal waves in the Sulu Sea. We found similar results as mentioned in Apel et al. (1985) and Liu et al.(1985). It is found that most of the internal waves are generated from the Sulu archipelago in southeast of the Sulu Sea and travels toward the Palawan Island. But, SAR images provide us more details. SAR images indicated that there are at least 3 sources. Wave fronts from each source will interact and be connected as a long wave crest with length of 100 km near the source. The 2D effect of "hand-in-hand" phenomenon is essential for the formation of huge internal solitons in the Sulu Sea. The SAR images also showed us some other features, such as no internal waves in the North East of the Sulu Sea, the refraction and diffraction of internal waves are clear in the shallow water South West of the Sulu Sea.

The calibration of mounting angles is one of the important works of the highly precise airborne laser scanning. In the paper, an effectively automated calibration of mounting angles is developed for improving the defect of the present hand-operated calibration. The results of the experiments have shown that the automated calibration developed here can obtain better and more reliable achievements than the present hand-operated calibration, because huge observations are used in the automated calibration.

Watershed unit has been regarded as an analyzed object for slopeland disaster assessment. With the fast growing progress of computer technologies, instead of manual operation, there is a trend of applying Digital Elevation Model (DEM) in automated watershed delineating and drainage network design. This study first focused on improving extraction method for automated watershed delineating. The concepts for depression outlets decision, looped drainage direction calculation, reasonable watersheds area delineation, and simulation of realistic drainage networks are all revised to propose a new approach for more reasonable and efficient in watershed delineation. Three major reservoir watersheds (Shihmen, Techi and Tsenwen) were chosen to calculate watershed geomorphologic and hydrologic information for verifying the suitability of proposed approach. Universal Soil Loss Equation (USLE) and Sediment Delivery Ratio (SDR) coupled with automated watershed delineation theory is applied to estimate watershed sediment yield. The system shows good performance for Shihmen, Techi, Tsenwen reservoir and Erzen creek watersheds. The results are summarized as follows: This study proposed surface-inclining approach to couple with elevation-differencing approach (Jenson and Domingue, 1988) for determining incipient drainage directions. The calculation of optimal outlet and drainage direction in the depressions can be performed using watershed depression approach with PROMETHEE theory. Compared with elevation-smoothing, depression-filling and repeatedly elevation-incrementing approaches, the drainage directions for Shihmen, Techi and Twensen reservoir watersheds calculated by watershed depression approach show more reasonable and realistic outcomes. The watershed area extracted for Shihmen, Techi and Twensen reservoir with the outlet located at the site of dam is 75634 ha, 52367 ha and 48396 ha, respectively. Due to inhomogeneous characteristics of geomorphology, geology, soil and/or climates of a watershed, the real drainage networks can not be delineated properly using single-threshold approach. Instead, a multiple-threshold approach is developed to cope with the real spatial distribution of streams in a watershed. Annual watershed sediment yield calculated for Shihmen, Techi, Twensen reservoirs and Erzen creek is 1928168 tons/yr, 1793742 tons/yr, 4807205 tons/yr and 5074396 tons/yr, and the corresponding annual erosion depth is 1.82mm, 2.45mm, 7.10mm and 25.81mm, respectively. Tsenwen reservoir and Erzen creek show higher erosion depth because of moderate mudstone distribution in the watershed. Model efficiency calculated using Nash and Sutcliffe (1970) for sediment yield estimation is 81.21%, the model (Ŷ=1.15Y, R^2=0.96*) shows significant correlation between estimated (Ŷ) and measured (Y) data.

Many applications, such as traffic management, urban planning, tourism, require 3D city model as their basic spatial information, which makes building extraction a hot research topic in the last two decades. This paper proposes a close-range photogrammetric procedure for building reconstruction based on model-image fitting. The model-image fitting process is applied in image orientation recovery and building part extraction. For image orientation recovery, previously measured building parts or outline can be used as control models. Orientation recovery is achieved by adjusting orientation parameters so as the image optimally fits to the control models. For building part extraction, the shape and pose parameters of a representative CSG primitive are adjusted to fit all of the corresponding images. The proposed procedure is especially suitable for updating or refining some building models in a city model built previously using aerial photogrammetry. Breaking through the traditional point measurement concept, this paper promotes a model (or object) based measurement concept to increase the efficiency of building reconstruction. Some experimental tests are demonstrated to show the feasibility of the proposed method. The accuracy assessment of the test results shows that the accuracy of proposed method is comparable to that of manual point measurement.

The objective of this investigation is to build up a geometric correction model for EROS A satellite images. The major works comprise orbit modeling and orthorectification. In addition to the Bundle Adjustment and On-board Data Correction Method in orbit modeling, we include least squares filtering technique to compensate for the local systematic errors. Considering the indirect approach in orthorectification, a Point-by-point Backprojection Method is developed. We also propose Patch Backprojection Method to minimize the computation load without significantly losing accuracy. Experimental results indicate that the proposed scheme may reach an accuracy of 2.5 pixels in orbit modeling for an image with an asynchronous ratio of 13. The accuracy of the generated orthoimage is equivalent to the one for orbit modeling.

Most of major rivers on the western coast of Taiwan flow into the Taiwan strait, and dense artificial constructions are distributed on the western coast, Besides, the areas of land subsidence induced by ground water over-pumping are also concentrated on the western coast. Therefore, the coastal zone of western Taiwan has more complicated topographic change than that of eastern Taiwan. In this study, multi-temporal remote sensing data, including aerial photographs dated from 1947 to 1949 and satellite images dated from 1973 to 1999, were used to analyze the change of western Taiwan coast. Aerial photographs were digitized, geometrically corrected and mosaicked before overlay analysis. On the other hand, satellites images were geometrically corrected, resampled and normalized before change analysis by means of various change detection methods. Results showed that the most serious erosion areas on the western coast include Bali coast, the southern coast of Hsinchu harbor, Poutsuliao coast, Howmeili reclaimed land coast, and the sandbars offshore the southwestern coast.