scholarly journals Ecological Niche Modelling using satellite data for assessing distribution of threatened species Ceropegia bulbosa Roxb.

2014 ◽  
Vol XL-8 ◽  
pp. 597-603
Author(s):  
S. Kumar ◽  
R. N. Kulloli ◽  
J. C. Tewari ◽  
J. P. Singh ◽  
A. Singh
Keyword(s):  
Digital Elevation Model ◽  
Satellite Data ◽  
Thermal Emission ◽  
Geographical Information ◽  
Niche Modelling ◽  
Digital Elevation ◽  
Bioclimatic Variables ◽  
Ground Truthing ◽  
Elevation Model ◽  
Ceropegia Bulbosa

<i>Ceropegia bulbosa</i> Roxb. is a narrow endemic, tuberous twiner of Asclepiadaceae family. It is medicinally important: tubers are nutritive and edible, leaves are digestive and a cure for dysentery and diarrhea. Exploitation for its tubers and poor regeneration of this species has shrunk its distribution. In order to know its present status, we report here the results of its appraisal in Rajasthan, using remote sensing and ground truthing in the past five years (2009&ndash;14). A base map of <i>C. bulbosa</i> was prepared using Geographical Information System (GIS), open source software Quantum GIS, SAGA. The Landsat Enhanced Thematic Mapper (ETM) +Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Global Digital Elevation Model (GDEM) Satellite Data were used in this study. ASTER and GDEM Data was clipped with district boundary and provided color range to get elevation information. A digital elevation model of Rajasthan physiography was developed from ASTER GDEM of 30-m resolution. GIS layers of Area of occurrences for <i>C. bulbosa</i> plant and elevation were created. This map along with topographic sheets of 1:50000 were used for field traversing and ground truthing as per GPS location inferred from map. Its geographic distribution was assessed using MaxEnt distribution modelling algorithm that employed 12 presence locality data, 19 bioclimatic variables, and elevation data. Results of this modelling predicted occurrence of <i>C. bulbosa</i> in the districts of Sirohi, Jalore, Barmer, Pali, Ajmer, Jhalawar, Dungarpur, Banswara, Baran, Kota, Bundi and Chittorgarh. Ground validation in these districts revealed its presence only at four places in three districts confirming its rarity. Analysis of dominance at their sites of occurrence revealed their poor populations and sub dominant status (RIV = 20&ndash;32) and very low density (2&ndash;12 plants per tenth ha).

Food Submergence Calculation and Analysis Using Digital Elevation Model and Geographical Information System

2014 ◽  
Vol 571-572 ◽  
pp. 792-795
Author(s):  
Xiao Qing Zhang ◽  
Kun Hua Wu
Keyword(s):  
Information System ◽  
Digital Elevation Model ◽  
Flood Control ◽  
Large Scale ◽  
Geographical Information ◽  
Economic Losses ◽  
Model Data ◽  
Digital Elevation ◽  
Elevation Model ◽  
Digital Elevation Model Data

Floods usually cause large-scale loss of human life and wide spread damage to properties. Determining flood zone is the core of flood damage assessment and flood control decision. The aim of this paper is to delineate the flood inundation area and estimate economic losses arising from flood using the digital elevation model data and geographic information system techniques. Flood extent estimation showed that digital elevation model data is very precious to model inundation, however, in order to be spatially explicit flood model, high resolution DEM is necessary. Finally, Analyses for the submergence area calculation accuracy.

scholarly journals The new remote-sensing-derived Swiss glacier inventory: I. Methods

2002 ◽  
Vol 34 ◽  
pp. 355-361 ◽  
Author(s):  
Frank Paul ◽  
Andreas Kääb ◽  
Max Maisch ◽  
Tobias Kellenberger ◽  
Wilfried Haeberli
Keyword(s):  
Satellite Data ◽  
Accuracy Assessment ◽  
Three Dimensional ◽  
Geographical Information ◽  
Glacier Inventory ◽  
Ratio Image ◽  
Digital Elevation ◽  
First Results ◽  
Gis Environment ◽  
Elevation Model

AbstractA new Swiss glacier inventory is to be compiled from satellite data for the year 2000. The study presented here describes two major tasks: an accuracy assessment of different methods for glacier classification with Landsat Thematic Mapper (TM) data and a digital elevation model (DEM); the geographical information system (GIS)-based methods for automatic extraction of individual glaciers from classified satellite data and the computation of three-dimensional glacier parameters (such as minimum, maximum and median elevation or slope and orientation) by fusion with a DEM. First results obtained by these methods are presented in Part II of this paper (Kääb and others, 2002). Thresholding of a ratio image from TM4 and TM5 reveals the best-suited glacier map. The computation of glacier parameters in a GIS environment is efficient and suitable for worldwide application. The methods developed contribute to the U. S. Geological Survey-led Global Land Ice Measurements from Space (GLIMS) project which is currently compiling a global inventory of land ice masses within the framework of global glacier monitoring (Haeberli and others, 2000).

scholarly journals DIGITAL ELEVATION MODEL FROM PRISM-ALOS AND ASTER STEREOSCOPIC DATA

2010 ◽  
Vol 6 (1) ◽  
Author(s):  
Bambang Trisakti ◽  
Ita Carolita ◽  
Firsan Ardi Pradana
Keyword(s):  
Digital Elevation Model ◽  
Spatial Resolution ◽  
Thermal Emission ◽  
Shuttle Radar Topography Mission ◽  
Contour Map ◽  
Resources Management ◽  
Digital Elevation ◽  
Other Information ◽  
Elevation Model ◽  
Terra Satellite

Digital Elevation Model (DEM) is a source to produce contour map, slope, and aspect information, which is needed for other information such as disaster and water resources management. DEM can be generated by several methods. One of them is parallax calculations from stereoscopic data of optical sensor. Panchromatic Remote-Sensing Instrument for Stereo Mapping (PRISM) sensor from Advanced LAnd Observation Satellite (ALOS) satellite and advance space borne Thermal Emission and Reflection Radiometer (ASTER) sensor from Terra Satellite is Japanese optical satellite sensor which have abilityto produce stereoscopic data. This study showed DEM generations from PRISM (2.5 m spatial resolution) and ASTER (15m spatial resolution) stereoscopic data using image matching and collinear model based on Orthobase-pro software. The Generated DEM from each sensor was compared to the DEM from Shuttle Radar Topography Mission (SRTM) X-C band with 30 m spatial resolution. The dependent on the pixel size from the DEM produced were also discussed. The result showed that both DEMs have similiar elevation and distribution pattern to the referenced DEM, but DEM for PRISM had higher relative accuracy (RMSE is 6.5 m) and Smoother pattern comparing to DEM from ASTER (RMSE is 10.2 m) Keyword : ASTER, DEM, PRISM, SRTM, Stereoscopic satellite data

scholarly journals Evaluation of the Accuracy of Digital Elevation Model Produced from Different Open Source Data

2019 ◽  
Vol 25 (8) ◽  
pp. 100-112
Author(s):  
Raghad Hadi Hasan
Keyword(s):  
Open Source ◽  
Digital Elevation Model ◽  
Thermal Emission ◽  
Shuttle Radar Topography Mission ◽  
Google Earth ◽  
Reference Points ◽  
Aster Gdem ◽  
Digital Elevation ◽  
Elevation Model ◽  
High Level

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.  

Assessment of ASTER global digital elevation model data for Arctic research

Polar Record ◽  
2011 ◽  
Vol 48 (1) ◽  
pp. 31-39 ◽  
Author(s):  
W. G. Rees
Keyword(s):  
Digital Elevation Model ◽  
Thermal Emission ◽  
Digital Elevation Models ◽  
Sampling Interval ◽  
Horizontal Resolution ◽  
The Arctic ◽  
Semivariogram Analysis ◽  
Digital Elevation ◽  
Elevation Data ◽  
Elevation Model

ABSTRACTA new source of digital elevation data, the advanced spaceborne thermal emission and reflection radiometer (ASTER) global digital elevation model (GDEM), has been freely available since 2009. It provides enormously greater coverage of the Arctic than previous satellite derived ‘global’ digital elevation models, extending to a latitude of 83 °N in contrast to 60 °N. The GDEM is described as a preliminary, research grade product. This paper investigates its accuracy in a number of specifically Arctic landscapes, including ice and snow, boreal forest, tundra and unvegetated terrain, using test sites in Svalbard, Iceland, Norway and Russia. Semivariogram analysis is used to characterise the magnitude and spatial correlation of errors in the GDEM products from the test sites. The analysis suggests that the horizontal resolution of the GDEM data is around 130 m, somewhat coarser than the sampling interval of 1 second of latitude and longitude. The vertical accuracy is variable, and the factors influencing it have not been systematically explored. However, it appears that the likely accuracy can be estimated from ‘stacking number’ data supplied with the elevation data. The stacking number is the number of independent digital elevation models averaged to generate the supplied product. Provided that this number is greater than around 6 the data have an rms accuracy of typically 5–10 m.

scholarly journals Modelo Digital de Elevação Hidrologicamente Consistente para a bacia do rio Doce: Elaboração e Análise (Conditioning hydrographic digital elevation model to rio Doce watershed: preparation and analysis)

2016 ◽  
Vol 9 (6) ◽  
pp. 1978
Author(s):  
Fernando Angelo Couto Cardoso ◽  
Deborah Luiza Poletto de Paula ◽  
Roberto Cezar de Almeida Monte Mor ◽  
James Lacerda Maia ◽  
Eliane Maria Vieira
Keyword(s):  
Digital Elevation Model ◽  
Thermal Emission ◽  
Flow Direction ◽  
Minas Gerais ◽  
Espírito Santo ◽  
Maximum Value ◽  
Digital Elevation ◽  
Elevation Model ◽  
Color Composite ◽  
Espirito Santo

O presente trabalho tem como objetivo a delimitação da bacia hidrográfica do rio Doce, que se encontra nos estados de Minas Gerais e Espírito Santo, e a elaboração do MDEHC em comparação com o MDE da mesma área, para a delimitação das Áreas de Preservação Permanente de topo de morro. Para a delimitação da bacia e a elaboração do modelo foi empregado o SIG ArcGIS e como base de dados o GDEM do ASTER e hidrografia disponibilizada pela ANA, foi empregada uma composição colorida do satélite LandSat RGB-345, para a verificação dos resultados e correção das falhas detectadas durante a execução do trabalho. Os resultados obtidos demonstraram a necessidade de modelos com qualidade satisfatória, para o correto desenvolvimento da metodologia de geração do modelo hidrológico, visto que houve variação na direção de fluxo com a mudança do MDE para o MDEHC. Também houve variação nos valores de altitude, dos dois modelos, enquanto que o valor o valor máximo obtido no MDEHC foi de 2637 m contra 2868 m no MDE. Esta variação na altitude é devida ao emprego da ferramenta para a eliminação das depressões espúrias, demonstrando que esta deve ser empregada com cautela. A variação no limite gerado com o MDEHC, em relação ao limite da ANA, demonstrou a necessidade da implementação de uma rotina computacional no SIG para a delimitação de bacias onde o exutório é constituído por uma região.     A B S T R A C T This study aims at delineation of rio Doce watershed, located in states of Minas Gerais and Espirito Santo, and the preparation of the Conditioning Hydrografic Digital Elevation Model (CHDEM), for the delineation of areas of permanent preservation on top of hills. For the delineation of the watershed and the development of the model was used the software ArcGIS® and as database the Global Digital Elevation Map (GDEM) of the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) including the Hydrography provided by Agência Nacional de Águas (ANA). It was made a color composite Landsat RGB-345 satellite, for the verification of the results and correction of faults detected during the execution of the work. The results showed the need for models with satisfactory quality to correct development of the hydrological model generation methodology, as there was variation in the flow direction with the change of the DEM for CHDEM. There was also variation in altitude values ​​of the two models, while the maximum value obtained in CHDEM was 2637 m against 2868 m in DEM. This variation in altitude is due to the use of the tool to eliminate spurious depressions, demonstrating that this should be used with caution. The variation in the boundary generated using CHDEM in relation to the ANA limit, showed the necessity of implementing a Geographic Information System (GIS) computational routine for delineation the watersheds where mouth comprises a region. Keywords: Hidrologyc model, ASTER, Geoprocessing.   

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