scholarly journals Comparison of Open Source DEM’s for Morphometric Analysis of Micro Watersheds: A Case Study from the Midlands of Kerala

Author(s):  
Md. Majeed Pasha ◽  
K. K. Sathian

Morphometric analysis with the help of remote sensing and GIS is now widely used to prioritise micro watersheds for planning interventions for soil and water conservation. DEM is the main digital data used to perform the morphometric analysis. There are different types of DEMs available to perform morphometric analysis using GIS techniques. But, no authentic information is available on the degree of accuracy levels of these DEMs to quantitatively determine various morphometric parameters for the watersheds in Kerala, with typical undulating and sloping terrain features. Hence, this research has been initiated to evaluate the quality of three popular DEMs viz. SRTM(Shuttle Radar Topography Mission), CARTOSAT(Cartography and satellite) and ASTER(Advanced spaceborne thermal emission and reflection Radiometer), each with 30 m spatial resolution. Two small sub watershed of Bharathapuzha river basin have been chosen for the study which are lying near to Valanchery town in Malappuram district. More than 21 morphometric parameters including drainage network, basin geometry, basin texture and basin relief characteristics were computed using these three types of DEMs and the outputs compared with google earth map. The results shows that the SRTM 30m DEM is characterized by higher accuracy compared to CARTOSAT and ASTER and has got better matching with google earth map data sources.

2015 ◽  
Vol 72 (7) ◽  
pp. 1168-1175 ◽  
Author(s):  
Manoj Kumar ◽  
Rohitashw Kumar ◽  
P. K. Singh ◽  
Manjeet Singh ◽  
K. K. Yadav ◽  
...  

The geographical information system (GIS) has emerged as an efficient tool in delineation of drainage patterns of watershed planning and management. The morphometric parameters of basins can address linear, areal and relief aspects. The study deals with the integrated watershed management of Baliya micro-watersheds, located in the Udaipur district of Rajasthan, India. Morphometric analysis in hydrological investigation is an important aspect and it is inevitable in the development and management of drainage basins. The determination of linear, areal and relief parameters indicate fairly good significance. The low value of the bifurcation ratio of 4.19 revealed that the drainage pattern has not been distorted by structural disturbance. The high value of the elongation ratio (0.68) compared to the circulatory ratio (0.27) indicates an elongated shape of the watershed. The high value of drainage density (5.39 km/km2) and stream frequency (12.32) shows that the region has impermeable subsoil material under poor vegetative cover with a low relief factor. The morphometric parameters of relief ratio (0.041) and relative relief (0.99%) show that the watershed can be treated using GIS techniques to determine the morphometric presence of dendritic drainage pattern, with a view to selecting the soil and water conservation measures and water harvesting.


2019 ◽  
Vol 25 (8) ◽  
pp. 100-112
Author(s):  
Raghad Hadi Hasan

This study aims to estimate the accuracy of digital elevation models (DEM) which are created with exploitation of open source Google Earth data and comparing with the widely available DEM datasets, Shuttle Radar Topography Mission (SRTM), version 3, and Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM), version 2. The GPS technique is used in this study to produce digital elevation raster with a high level of accuracy, as reference raster, compared to the DEM datasets. Baghdad University, Al Jadriya campus, is selected as a study area. Besides, 151 reference points were created within the study area to evaluate the results based on the values of RMS.Furthermore, the Geographic Information System (GIS) was utilized to analyze, imagine and interpolate data in this study. The result of the statistical analysis revealed that RMSE of DEM related to the differences between the reference points and Google Earth, SRTM DEM and ASTER GDEM are 6.9, 5.5 and 4.8, respectively. What is more, a finding of this study shows convergence the level of accuracy for all open sources used in this study.  


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Vesna R. Stojanović ◽  
Ivan D. Jovanović ◽  
Sladjana Z. Ugrenović ◽  
Ljiljana P. Vasović ◽  
Vladimir S. Živković ◽  
...  

Number of sclerotic glomeruli increases during the aging process. Consequently, majority of remained nonsclerosed glomeruli become hypertrophic and some of them sclerotic, too. The aim of this study was to quantify the size and connective tissue content of nonsclerosed glomeruli and to evaluate the percentage of hypertrophic ones in examined human cases during the aging. Material was right kidney's tissue of 30 cadavers obtained during routine autopsies. Cadavers were without previously diagnosed kidney disease, diabetes, hypertension, or any other systemic disease. Tissue specimens were routinely prepared for histological and morphometric analysis. Images of the histological slices were analyzed and captured under 400x magnification with digital camera. Further they were morphometrically and statistically analyzed with ImageJ and NCSS-PASS software. Multiple and linear regression of obtained morphometric parameters showed significant increase of glomerular connective tissue area and percentage. Cluster analysis showed the presence of two types of glomeruli. Second type was characterized with significantly larger size, connective tissue content, and significantly lower cellularity, in relation to the first type. Such glomeruli might be considered as hypertrophic. First type of glomeruli was predominant in younger cases, while second type of glomeruli was predominant in cases older than 55 years.


Author(s):  
M. Kaur ◽  
S. Singh ◽  
V. K. Verma ◽  
B. Pateriya

Morphometric analysis is the measurement and mathematical analysis of the landforms. The delineation of drainage system is of utmost importance in understanding hydrological system of an area, water resource management and it's planning in an effective manner. Morphometric analysis and land use change detection of two sub-watersheds namely Kukar Suha and Ratewal of district Shahid Bhagat Singh Nagar, Punjab, India was carried out for quantitative description of drainage and characterisation. The stream order, stream number, stream length, mean stream length, and other morphometric analysis like bifurcation ratio, drainage density, texture, relief ratio, ruggedness number etc. were measured. The drainage pattern of Kukar Suha and Ratewal is mainly dendritic. The agriculture and settlements came up along the drainage network causes the pattern disturbance in the watershed. The study was undertaken to spotlight the morphometric parameters, their impact on the basin and the land use land cover changes occurred over the period of time. Morphometric parameters such as linear aspect, areal aspect and relief aspect of the watershed are computed. The land use/land cover change was extracted from LISS IV Mx + Cartosat1 PAN data. ASTER data is used to prepare DEM (digital elevation model) and geographical information system (GIS) was used to evaluate various morphometric parameters in ArcGIS10 software.


Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1138 ◽  
Author(s):  
Anurag Malik ◽  
Anil Kumar ◽  
Daniel Prakash Kushwaha ◽  
Ozgur Kisi ◽  
Sinan Q. Salih ◽  
...  

Among several components of watershed prioritization, morphometric parameters are considered to be essential elements for appropriate water resource planning and management. In the current study, nine hilly sub-watersheds are prioritized using novel hybrid model based on morphometric variables analysis at Bino Watershed (BW) located in the upper Ramganga basin, India. The proposed model is based on the hybridization of principal component analysis (PCA) with weighted-sum approach (WSA), presenting a single-frame methodology (PCWSA) for sub-watershed prioritization. The prioritization process was conducted based on several morphometric parameters including linear, areal, and shape. The PCA was performed to identify the significant correlated factor-loading matrix whereas WSA was established to provide the weights for the morphometric parameters and fix their priority ranking (PR) to be categorized based on compound factor value. The findings showed that 37.81% of total area is under highly susceptible zone sub-watersheds (SW-6 and SW-7). This is verifying the necessity for appropriate soil and water conservation measures for the area. The proposed hybrid methodology demonstrated a reliable approach for water resource planning and management, agriculture, and irrigation activities in the study region.


Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1293 ◽  
Author(s):  
Hao Wang ◽  
Hu Zhao

The Taohe River Basin is the largest tributary and an important water conservation area in the upper reaches of the Yellow River. In order to investigate the status of soil erosion in this region, we conducted a research of soil erosion. In our study, several parameters of the revised universal soil loss equation (RUSLE) model are extracted by using Google Earth Engine. The soil erosion modulus of the Taohe River Basin was calculated based on multi-source data, and the spatio-temporal variation characteristics of the soil erosion intensity were analyzed. The results showed the following: (1) the average soil erosion modulus of the Taohe River Basin in 2000, 2005, 2010, 2015 and 2018 were 1424, 1195, 1129, 1099 and 1124 t·ha−1·year−1, respectively, and the overall downward trend was obvious. (2) The ranges of soil erosion in the Taohe River Basin in 2000, 2005, 2010, 2015 and 2018 are basically the same—mainly with slight erosion—and the soil erosion in the middle and lower reaches was more serious. (3) When dealing with the vegetation cover factor and conservation practice factor in the RUSLE model, Google Earth Engine provided a new approach for soil erosion investigation and monitoring over a large area.


2012 ◽  
Vol 518-523 ◽  
pp. 5663-5667
Author(s):  
Shi Wei Li ◽  
Ji Long Zhang ◽  
Jian Sheng Yang

Vegetation covering situation is very important for the quality of air quality, soil and water conservation ability and soil forming in an area. By using the remote sensing image of Taiyuan Valley Plain, the application of Normalized Difference Vegetation Index (NDVI) and unsupervised classification, the vegetation coverage map which includes non-cultivated land disposition and cultivated land disposition was obtained using ERDAS Imagine software. To evaluate the accuracy of the results, 200 points were sampled randomly, the high spatial resolution remote sensing image from Google Earth was used as the reference. The overall classification accuracy is 82%, with the Kappa statistic of 0.81. By counting the totally pixel acreage, it was gotten that the vegetation coverage was 46% and the cultivated land coverage ratio was 31% in the study area.


2021 ◽  
Vol 13 (14) ◽  
pp. 7967
Author(s):  
Usha Poudel ◽  
Haroon Stephen ◽  
Sajjad Ahmad

Southern California’s Imperial Valley (IV) faces serious water management concerns due to its semi-arid environment, water-intensive crops and limited water supply. Accurate and reliable irrigation system performance and water productivity information is required in order to assess and improve the current water management strategies. This study evaluates the spatially distributed irrigation equity, adequacy and crop water productivity (CWP) for two water-intensive crops, alfalfa and sugar beet, using remotely sensed data and a geographical information system for the 2018/2019 crop growing season. The actual crop evapotranspiration (ETa) was mapped in Google Earth Engine Evapotranspiration Flux, using the linear interpolation method in R version 4.0.2. The approx() function in the base R was used to produce daily ETa maps, and then totaled to compute the ETa for the whole season. The equity and adequacy were determined according to the ETa’s coefficient of variation (CV) and relative evapotranspiration (RET), respectively. The crop classification was performed using a machine learning approach (a random forest algorithm). The CWP was computed as a ratio of the crop yield to the crop water use, employing yield disaggregation to map the crop yield, using county-level production statistics data and normalized difference vegetation index (NDVI) images. The relative errors (RE) of the ETa compared to the reported literature values were 7–27% for alfalfa and 0–3% for sugar beet. The average ETa variation was low; however, the spatial variation within the fields showed that 35% had a variability greater than 10%. The RET was high, indicating adequate irrigation; 31.5% of the alfalfa and 12% of the sugar beet fields clustered in the Valley’s central corner were consuming more water than their potential visibly. The CWP showed wide variation, with CVs of 32.92% for alfalfa and 25.4% for sugar beet, signifying a substantial scope for CWP enhancement. The correlation between the CWP, ETa and yield showed that reducing the ETa to approximately 1500 mm for alfalfa and 1200 mm for sugar beet would help boost the CWP without decreasing the yield, which is nearly equivalent to 44.52M cu. m (36,000 acre-ft) of water. The study’s results could help water managers to identify poorly performing fields where water conservation and management could be focused.


1993 ◽  
Vol 46 (2) ◽  
pp. 208-222 ◽  
Author(s):  
Peter J. Bennett

A GEC Marconi Avionics/MoD joint–funded integrated, digital terrain system called ' PENETRATE ' (passive enhanced navigation with terrain referenced avionics) is in its fourth year of flight trials on a Hunter fast–jet aircraft at the Defence Research Agency, Farnborough. Although originally designed to enable military aircraft to penetrate enemy defences at low level in poor weather conditions and at night, the system also has a direct read across to civil air transport operations. The heart of the PENETRATE system is a digital data–store housing a three–dimensional model of the terrain including cultural details, obstructions and tactical intelligence information.PENETRATE incorporates terrain-referenced navigation to provide accurate position information relative to the ground contours. A sophisticated digital map displays navigation information and includes intelligence and intervisibility overlays. Head-up visual enhancement options are provided which can be tailored to the outside visibility. These comprise monochrome skeletal perspective displays which are superimposed on the outside world view and also on the forward-looking infra-red (FUR) scene. The display enhancements range from obstruction cues through ridge line overlays to skeletal perspective terrain presentations.This paper covers the philosophy and architecture of PENETRATE together with details of the demonstration system. It also discusses the capability of this digital terrain system to enhance the safety of civil aircraft approaches into difficult airports such as Kathmandu and Hong Kong.


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