Impact of Elevation - Glaciation - Tectonics on landscape characteristics of the watersheds in Bhagirathi valley, Garhwal Himalaya

Terrain attributes of watersheds i.e., mean , maximum, minimum elevation, mean slope elevation, mean aspect, HI (Hypsometrical Integral), Plan and Profile curvature index were determined using ASTER DEM in Bhagirathi basin, Uttaarakhand. These attributes are used in determine the impact of elevation, glaciations and tectonic processes on terrain characteristics of the watersheds. The scatter diagrame between altitude and terrain attribute were used to analyse th impact of altitude and impact of glacition is revealed through Box Whisker diagram using moderate and fully glacier watersheds. The results indicated that permanent snowline altitude is important that determine the watershed density in particular elevation and bear direct relationship with area and degree of glaciations. It is found that slope, STD of elevation in glacier basin, profile and plan curvature, relief influenced by glaciations.

Characterizing the Landscape Structure of Urban Wetlands Using Terrain and Landscape Indices

Several studies have shown human impacts on urban wetlands. These impacts are mostly studied at broad scales, which may generalize and aggregate important information needed for landscape quantification or terrain analysis. This situation can weakly or inappropriately address the structure of wetland landscapes, thus affecting the assessment of the quantities and qualities of terrestrial wetland habitats. To address these issues for urban wetland dynamics, this study proposes the use of landscape and terrain indices to characterize the landscape structure of urban wetlands at a fine scale in order to assess its usefulness in contributing to wildlife sustainability. To achieve this goal, secondary terrain attribute data are integrated with an object-based satellite image classification at the wetland and watershed level. The result reveals a general swell in wetland coverage at the watershed level. Further analysis shows the size and shape complexities, and edge irregularities are increased significantly at the patch level but slightly at the watershed level. Terrain analysis further reveals a potential increase in wetness and decrease in stream power vulnerability for most of the major wetlands under study. These results suggest that terrain and landscape indices are effective in characterizing the structure of urban wetlands that supports socio-ecological sustainability.

Effective Identification of Terrain Positions from Gridded DEM Data Using Multimodal Classification Integration

Terrain positions are widely used to describe the Earth’s topographic features and play an important role in the studies of landform evolution, soil erosion and hydrological modeling. This work develops a new multimodal classification system with enhanced classification performance by integrating different approaches for terrain position identification. The adopted classification approaches include local terrain attribute (LA)-based and regional terrain attribute (RA)-based, rule-based and supervised, and pixel-based and object-oriented methods. Firstly, a double-level definition scheme is presented for terrain positions. Then, utilizing a hierarchical framework, a multimodal approach is developed by integrating different classification techniques. Finally, an assessment method is established to evaluate the new classification system from different aspects. The experimental results, obtained at a Loess Plateau region in northern China on a 5 m digital elevation model (DEM), show reasonably positional relationship, and larger inter-class and smaller intra-class variances. This indicates that identified terrain positions are consistent with the actual topography from both overall and local perspectives, and have relatively good integrity and rationality. This study demonstrates that the current multimodal classification system, developed by taking advantage of various classification methods, can reflect the geographic meanings and topographic features of terrain positions from different levels.

Establishes the Precise Three-Dimensional Terrain Method Study Based on Anudem

Take a typical region in the Loess Plateau of North Shaanxi Province zone as the study area.Based on relief map with a scale of 1:1000 to generate accurate 3D terrain DEM using Anudem algorithm. Compared with the production of Anudem method TIN method and Kriging method between DEM. DEM accuracy evaluation including value target, profile and slope and terrain attribute visualization, contour line playbacking and different differential value algorithm result variance analysis. The DEM difference that the result demonstrates that the different algorithm obtains is big, and DEM precision of Anudem method production is best, can very good response precise three-dimensional terrain.