Evaluation of topographic index in relation to terrain roughness and DEM grid spacing

Mukherjee, Samadrita; Mukherjee, Sandip; Garg, Rahul; Bhardwaj, Ashutosh; Raju, P. L. N.

doi:10.1007/s12040-013-0292-0

Cited by 59 publications

(29 citation statements)

References 50 publications

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“…In this study, the TRI was used as the amount of elevation difference among the adjacent cells of a DEM (Mukherjee et al, 2013b). The residuals in elevation between a grid cell and its eight neighbors were derived, and the RMSE of the elevation differences was calculated as the TRI.…”

Section: Resultsmentioning

confidence: 99%

A geomorphology-based approach for digital elevation model fusion – case study in Danang city, Vietnam

et al. 2014

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Abstract.Global digital elevation models (DEM) are considered a source of vital spatial information and find wide use in several applications. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global DEM (GDEM) and Shuttle Radar Topographic Mission (SRTM) DEM offer almost global coverage and provide elevation data for geospatial analysis. However, GDEM and SRTM still contain some height errors that affect the quality of elevation data significantly. This study aims to examine methods to improve the resolution as well as accuracy of available free DEMs by data fusion techniques and evaluating the results with a high-quality reference DEM. The DEM fusion method is based on the accuracy assessment of each global DEM and geomorphological characteristics of the study area. Land cover units were also considered to correct the elevation of GDEM and SRTM with respect to the bare-earth surface. The weighted averaging method was used to fuse the input DEMs based on a landform classification map. According to the landform types, the different weights were used for GDEM and SRTM. Finally, a denoising algorithm (Sun et al., 2007) was applied to filter the output-fused DEM. This fused DEM shows excellent correlation to the reference DEM, having a correlation coefficient R 2 = 0.9986, and the accuracy was also improved from a root mean square error (RMSE) of 14.9 m in GDEM and 14.8 m in SRTM to 11.6 m in the fused DEM. The results of terrain-related parameters extracted from this fused DEM such as slope, curvature, terrain roughness index and normal vector of topographic surface are also very comparable to reference data.

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Section: Resultsmentioning

confidence: 99%

A geomorphology-based approach for digital elevation model fusion – case study in Danang city, Vietnam

et al. 2014

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“…In this study, second-order finite difference was used. Four Closest Neighbours (FCN) algorithm (Guth 1995;Raaflaub and Collins 2006;Mukherjee et al 2013a) was used for computing slope. It takes into account two orthogonal components of slope in x and y direction.…”

Section: Calculation Of Slopementioning

confidence: 99%

“…Like any spatial dataset, DEMs are also subjected to different types of error (Rodgriguez et al 2006), deficient orientation of stereo images (systematic error) when photogrammetrically determining elevation values (Mukherjee et al 2011), and some unknown combinations of errors (random error) which cannot be avoided. The other issues related to DEM accuracy are grid spacing and interpolation techniques (Mukherjee et al 2013a).…”

Section: Introductionmentioning

confidence: 99%

Accuracy of Cartosat-1 DEM and its derived attribute at multiple scale representation

Mukherjee

Bhardwaj

et al. 2015

J Earth Syst Sci

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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.

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“…Several researchers have concluded that the DEM grid size influences the slope gradient and slope length factors (Gao 1997;Lin et al 2013;Mukherjee et al 2013). The average of slope gradient decreased with increasing DEM grid size (Gao 1997;David and McCabe 2000;Thompson et al 2001;Wang and Wang 2009).…”

Section: Introductionmentioning

confidence: 99%

Effects of DEM grid size on predicting soil loss from small watersheds in China

Cao

Liu

et al. 2014

Environ Earth Sci

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The topography (slope gradient and slope length) has an important effect on soil erosion by water. Slope gradient and slope length factor are the parameters of the universal soil loss equation that is commonly used to predict soil erosion. These factors are usually extracted from the digital elevation model (DEM). Thus the DEM grid size will influence topographic factors and therefore soil loss calculation. The purpose of this study was to investigate the effect of DEM grid size on the topographic factors and therefore soil loss prediction on a typical watershed in northeast of China. The site for the case study was Dontaigou watershed which is located at Huairou district, Beijing, China. Contour lines of 2 m interval digitized from 1:2,000 scale of topographic maps were used to generate DEM with grid size of 2 m. The DEMs with grid sizes of 3-30 m, at 1 m intervals, were created using the nearest neighbor resampling method. In total, 29 DEMs with different grid sizes were obtained. Four different scenarios of the channel initiation threshold were used to extract the drainage channel and let the slope length cutoff. Chinese soil loss equation was used to predict the soil loss. The results show that DEM grid size had different effects on the topographic factor. The average calculated slope steepness factor decreased with the increase of the DEM grid size in a linear decay function. The average slope length factor increased with DEM grid size when the drainage channel was not considered. It slightly decreased with DEM grid size and then increased when the drainage channel suitable for DEM grid size was used. However, comparing different grid sizes, the LS factor and the soil loss prediction of DEM grid size less than or equal to 10 m were close to those of 2 m DEM. The channel initiation threshold had effects on the extraction of slope length and then slope length factor. We found that the effect of DEM grid size on predicting soil loss depends on selection of suitable channel initiation threshold.

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Evaluation of topographic index in relation to terrain roughness and DEM grid spacing

Cited by 59 publications

References 50 publications

A geomorphology-based approach for digital elevation model fusion – case study in Danang city, Vietnam

A geomorphology-based approach for digital elevation model fusion – case study in Danang city, Vietnam

Accuracy of Cartosat-1 DEM and its derived attribute at multiple scale representation

Effects of DEM grid size on predicting soil loss from small watersheds in China

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