Gully feature mapping is an indispensable prerequisite for the motioning and control of gully erosion which is a widespread natural hazard. The increasing availability of high-resolution Digital Elevation Model(DEM) a...Gully feature mapping is an indispensable prerequisite for the motioning and control of gully erosion which is a widespread natural hazard. The increasing availability of high-resolution Digital Elevation Model(DEM) and remote sensing imagery, combined with developed object-based methods enables automatic gully feature mapping. But still few studies have specifically focused on gully feature mapping on different scales. In this study, an object-based approach to two-level gully feature mapping, including gully-affected areas and bank gullies, was developed and tested on 1-m DEM and Worldview-3 imagery of a catchment in the Chinese Loess Plateau. The methodology includes a sequence of data preparation, image segmentation, metric calculation, and random forest based classification. The results of the two-level mapping were based on a random forest model after investigating the effects of feature selection and class-imbalance problem. Results show that the segmentation strategy adopted in this paper which considers the topographic information and optimal parameter combination can improve the segmentation results. The distribution of the gully-affected area is closely related to topographic information, however, the spectral features are more dominant for bank gully mapping. The highest overall accuracy of the gully-affected area mapping was 93.06% with four topographic features. The highest overall accuracy of bank gully mapping is 78.5% when all features are adopted. The proposed approach is a creditable option for hierarchical mapping of gully feature information, which is suitable for the application in hily Loess Plateau region.展开更多
In this study, a new method for quantitative and efficient measurement for the ground surface movement was developed. The feature of this technique is to identify geomorphic characteristics by image matching analysis,...In this study, a new method for quantitative and efficient measurement for the ground surface movement was developed. The feature of this technique is to identify geomorphic characteristics by image matching analysis, using the intelligent images made from high resolution DEM(Digital Elevation Model). This method is useful to extract the small ground displacement where the surface shape was not intensely deformed.展开更多
Landsat ETM+ data and SRTM DEM data were used to delineate the geological, structural and geomorphological features in the intermontane Imphal Valley in Manipur, India. This area has simple geology, structural feature...Landsat ETM+ data and SRTM DEM data were used to delineate the geological, structural and geomorphological features in the intermontane Imphal Valley in Manipur, India. This area has simple geology, structural features and there- fore provides an ideal site to test the utility of remote sensing and GIS techniques in geological studies. The various techniques such as band ratioing, Principal Component Analysis (PCA) and generation of FCC (False Colour Composite) were employed on ETM+ data. The SRTM DEM data is used in generating the west-east transects of altitude pro- files in the valley for characterization of altitude levels of the litho-units. DEM derived drainage network and relative drainage density in the basin were used in interpreting the location of fault plane in the valley. The slope and lineament maps were prepared using SRTM DEM. It suggests that entire valley is covered by very low slope (0? - 9?). Lineaments are oriented N-S, 180? while in south-east of valley the direction is largely NW-SE. The change in lineament direction suggests that the eastern side of the valley is controlled by Indonesian Island arc strike direction.展开更多
This paper develops a method which can be used to assist aerial navigation by determining the spatial position and posture of the aerial photographic plane. After the method, aerial images match known DEM to capture t...This paper develops a method which can be used to assist aerial navigation by determining the spatial position and posture of the aerial photographic plane. After the method, aerial images match known DEM to capture the spatial position and posture. Some aerial images and terrain data are used to testify our method. Compared with those of analytic and stereo mappers, the results by our method are correspondent to real measurements well.展开更多
基金Under the auspices of Priority Academic Program Development of Jiangsu Higher Education Institutions,National Natural Science Foundation of China(No.41271438,41471316,41401440,41671389)
文摘Gully feature mapping is an indispensable prerequisite for the motioning and control of gully erosion which is a widespread natural hazard. The increasing availability of high-resolution Digital Elevation Model(DEM) and remote sensing imagery, combined with developed object-based methods enables automatic gully feature mapping. But still few studies have specifically focused on gully feature mapping on different scales. In this study, an object-based approach to two-level gully feature mapping, including gully-affected areas and bank gullies, was developed and tested on 1-m DEM and Worldview-3 imagery of a catchment in the Chinese Loess Plateau. The methodology includes a sequence of data preparation, image segmentation, metric calculation, and random forest based classification. The results of the two-level mapping were based on a random forest model after investigating the effects of feature selection and class-imbalance problem. Results show that the segmentation strategy adopted in this paper which considers the topographic information and optimal parameter combination can improve the segmentation results. The distribution of the gully-affected area is closely related to topographic information, however, the spectral features are more dominant for bank gully mapping. The highest overall accuracy of the gully-affected area mapping was 93.06% with four topographic features. The highest overall accuracy of bank gully mapping is 78.5% when all features are adopted. The proposed approach is a creditable option for hierarchical mapping of gully feature information, which is suitable for the application in hily Loess Plateau region.
文摘In this study, a new method for quantitative and efficient measurement for the ground surface movement was developed. The feature of this technique is to identify geomorphic characteristics by image matching analysis, using the intelligent images made from high resolution DEM(Digital Elevation Model). This method is useful to extract the small ground displacement where the surface shape was not intensely deformed.
文摘Landsat ETM+ data and SRTM DEM data were used to delineate the geological, structural and geomorphological features in the intermontane Imphal Valley in Manipur, India. This area has simple geology, structural features and there- fore provides an ideal site to test the utility of remote sensing and GIS techniques in geological studies. The various techniques such as band ratioing, Principal Component Analysis (PCA) and generation of FCC (False Colour Composite) were employed on ETM+ data. The SRTM DEM data is used in generating the west-east transects of altitude pro- files in the valley for characterization of altitude levels of the litho-units. DEM derived drainage network and relative drainage density in the basin were used in interpreting the location of fault plane in the valley. The slope and lineament maps were prepared using SRTM DEM. It suggests that entire valley is covered by very low slope (0? - 9?). Lineaments are oriented N-S, 180? while in south-east of valley the direction is largely NW-SE. The change in lineament direction suggests that the eastern side of the valley is controlled by Indonesian Island arc strike direction.
基金uisition of Directional Funded by the National 973 Project (No.2003CB415205).
文摘This paper develops a method which can be used to assist aerial navigation by determining the spatial position and posture of the aerial photographic plane. After the method, aerial images match known DEM to capture the spatial position and posture. Some aerial images and terrain data are used to testify our method. Compared with those of analytic and stereo mappers, the results by our method are correspondent to real measurements well.
