An earthquake of Ms 8 struck Wenchuan County, western Sichuan, China on May 12th, 2008. This devastating earthquake was caused by Longmen Shan thrust belt with more than 300km fault rupture. The displacement of the Longmen Shan fault is 6m in average. The large ground motion of Wenchuan Earthquake did not only damage the buildings and killed more than 70,000 people, but also caused huge amount of landslides in the mountainsides. Therefore, the geohazards monitoring will be also the important issue after Wenchuan earthquake. This study area is located in the Bei-Chuan of Sichuan province. In order to evaluate the geohazards of Wenchuan Earthquake rapidly, the spectrum images of FORMOSA-II, TerraSAR, and ASTER satellites was adopted for interpreting the landslide area and the reservoirs of the landslide dam. The pair of images of ASTER satellites was adopted for producing the DEM. Furthermore, the satiability of the landslide dam was evaluated by extracting the elevation from DEM and the calculating the area of landslide dam reservoir in GIS. From the experience of this case study, using multi-scale satellite images could provide information for geohazard mitigation planning rapidly, and prevent damage and reduce loss validly.

The mobile mapping system is one of the most important civil applicaiotns of INS/GPS integrated systems because of its rapidly direct geo-referencing capability which is useful in Geospatial Information acquisition for Taiwan, a small island with high population. In this study, a low cost INS/GPS integrated POS, was developed and applied to provide the positional and orientation information seamlessly. For system calibration, a high-accuracy ground control field was established by means of the ground survey. The measurements collected by the proposed system from the control field were added to the bundle adjustment procedure to solve the lever-arm and boresight angles between those image sensors. Based on the parameters obtained after calibration, the proposed system could perform direct geo-referencing tasks. This study describes the architecture of the proposed system and the establishment of the control field. Then a two-step approach with some strategies are proposed to conduct system calibration. Finally, the system test, error analysis, and the results of system calibration are presented. The results of the experiment depict that the accuracy of direct geo-referencing capability in term of the positioning accuracy of the proposed is less than 15cm(HPE) and 28cm (3D). The analysis proves the stability of proposed system is high, and the applications in the disaster assessment or the highway inventory investigation are also feasible. While the maturity of related technology becomes higher, the system can provide more contribution in the future.

This study aims to improve on stream flow simulation using the Generalized Watershed Loading Functions (GWLF) model by including remote sensing techniques to estimate the cover coefficient (CV), as well as integrating the SEBAL model, the CGCM1 model, and the Markov model to predict land-use and ET changes. Moreover, the results were adopted to assess the effect of environmental changes on future hydrology or the north of Taiwan. The processes include land-use classification using hybrid approach and Landsat-5 TM images, a comparison of stream flow simulations using the GWLF model with two CV values derived from remote sensing and traditional methods, and finally the prediction of future land-use and CV parameters for assessing the effect of land-use change and ET change. The results indicated that the study area was classified into seven land-use types with 89.09% classification accuracy. The stream flows simulated by two estimated CVs were different, and the simulated stream flows using the remote sensing approach presented more accurate hydrological characteristics than a traditional approach. In addition, the consideration of land-use change and ET change indeed affected the predicted stream flows under climate change conditions. The results of the hydrology analysis based on the SRES scenarios of CGCM1 model predicted that the river flows of north Taiwan will become greater due to the effects of climate change, land-use change and ET change. Therefore, the results obtained from this study can be extrapolated to the future studies of global environmental change and water resource management.

The coordinates of interested points can be determined by space intersection of the images, whose interior and exterior orientation parameters are determined from the navigation and calibration data. Obtaining conjugate points of image sequences by image matching is much more efficient than manual measurement. However the factors of scale variations, different field of view, and occlusion may result in incorrect matching points. In this research, image matching in object space with virtual surface is proposed to overcome the problem of matching in image space. The process to filter out occluded images is proposed, and the remaining useful images are kept for multiple image matching with multiple windows, which is developed to ease the problems caused by complex backgrounds. The test results of the experiments show the proposed method can deliver correct matching results good to about 90%. The determined coordinates are about 10 cm in precision, and about 50 cm in accuracy. Accuracy can be improved, if the positioning and orientation system of the MMS can be improved.

Both location and environment information are the key reference for either buying parties or selling parties in real estate market, however consumers acquired them hardly. It will provide consumers the information, by objectivity and quantity, through photo-realistic cyber city based on Web 3D GIS. Due to large amount of geo-spatial data, narrow network bandwidth, limited computation ability of server, and non-superior performance of client, it is so difficult to perform the photo-realistic cyber city on Web 3D GIS server. Thus, at the beginning, a multi-scale building modeling based on GIS 3D modeling tool is proposed in this study. The degree of scale for a certain building is decided according to its importance and relative location to a major road. The result showed the geo-data volume was decreased largely, and the efficiency during data transfer on the Internet is increased, and the cost in production was also reduced, and therefore its applicability in Web-based 3D GIS is raised. In real estate applications based on the designed Web-based 3D GIS platform, a location and physical environment query system to assist users to choose the optimum house has been thus established. It applied buffer-zone analysis tool on location queries, and other GIS spatial analysis tools, i.e. shadow, view-shed, terrain-profile and sea-level rising analysis, on physical environmental queries. The result showed users can obtain the location and physical environment information of real estate in quantity via this query system.

Instrumentation plays an important role in the development of the surveying methodology. The reciprocal relationship of demand and supply also imposes large influence to the progress of change. Particularly in the past ten years, aerial survey has experienced tremendous change in Taiwan. After reviewing the progress of surveying methodology and the practice of aerial survey in Taiwan, five issues are identified, namely, the surveying datum, the aerial survey permit application regulation, the confrontation of spatial information dissemination policy and national defense and security, the internationalization, and the long term plan with coordination. All these five issues are of different time frames. Although there are technique content in these five issues, they are largely in the policy and management level. The fast progress of communication and transportation technology has almost removed the restriction arising from the geographic distance. This made the competitions and mutual influences across boarder. The award for a right decision or movement will arrive quick. It is sincerely hoped that the aerial survey in Taiwan will progress well in the upcoming decade.