No abstract

Shoreline prediction models have the capability of integrating geoinformatics within them. The present study is conducted on the 142 km-long coastline of Puri district, India. It aims to analyze the change in coastline due to erosion/accretion and provide best estimate of future shoreline positions based on past shorelines. A simple mathematical model, End Point Rate (EPR), has been used to calculate the rate of change of shoreline and its future positions, based on empirical observations. The erosional/accretional scenario has also been analysed by delineating the shoreline from Landsat imageries of 1972, 2001 and 2010. It is found that the northern part of Puri, in the vicinity of Kushabhadra estuary and Chandrabhaga beach undergo high rates of erosion. Based on the delineated shoreline, the short term (2015) and long term (2025) shoreline positions have been predicted.

Topographic index is an important attribute of digital elevation model (DEM) which indicates soil saturation. It is used for estimation of runoff , soil moisture, depth of ground water and hydrological simulation. Topographic index is derived from DEMs; hence the accuracy of DEM influences its computation. Commonly the raster based grid DEM is widely used to simulate hydrological model parameter, and accuracy varies with respect to DEM grid size and morphological characteristics of terrain. In this study topographic index is evaluated in terms of DEM grid size and terrain roughness. The study was carried out on four small watersheds, having different roughness characteristics, located over the Himalayan terrain. Topographic index surface is derived for each watershed from different grid spacing DEM (10-150 m), analysed and validated. It is found that DEM grid spacing affects the topographic index. The surface representation is smooth in the coarse grid spacing and the pattern of topographic index changes with grid spacing. The spatial autocorrelation of topographic index surface reduces when calculated from larger spacing DEM. The mean of the topographic index surface increases and standard deviation decreases with the increase of grid spacing and the effect is more pronounced in the rough terrain. Accuracy of the topographic index is also evaluated with respect to grid spacing and terrain roughness by comparing the topographic index surface with respect to reference data (10 m grid spacing topographic index surface). The RMSE and mean error of topographic index surface increases in larger grid spacing and the effect is more in rugged terrain.

Digital Elevation Model (DEM) provides basic information about terrain relief and is used for morphological characterisation, hydrological modelling and infrastructural studies. This paper investigates the accuracy of DEM and its derived attributes in multiple scales. This study was carried out for a part of Shiwalik Himalaya using Cartosat-1 stereo pair data. DEM at various cell sizes were generated and information content was compared using mean elevation, variance and entropy statistics. Various post-spacing DEMs were validated to understand variation in vertical accuracy along different scales. The vertical accuracy (3.14-7.24 m) is affected in larger spacing DEM and elevation is underestimated. Slope of terrain also has similar impacts. The DEM and slope accuracy are also affected by the terrain roughness while assessing coarser grid size.