scholarly journals Potencial para la exploración de aguas subterráneas en la Demarcación Hidrográfica Puyango Catamayo, Ecuador, utilizando un proceso de análisis jerárquico basado en SIG y teledetección

2018 ◽  
pp. 135
Author(s):  
V.X. Macas-Espinosa ◽  
K.F. López-Escobar
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Drainage Density ◽  
Groundwater Potential ◽  
Groundwater Exploration ◽  
Point Of View ◽  
Primary Data ◽  
Analytic Hierarchy ◽  
Potential Index ◽  
Elevation Model

<p>The objective of this study is to apply geographic information systems and remote sensing techniques to map potential areas for groundwater exploration in the Puyango Catamayo hydrographic demarcation, based on free input data. The research’s primary data are a digital elevation model, satellite images, regional geology and rainfall. From the methodological point of view, Multi-Criteria Decision Analysis is applied, using an Analytic Hierarchy Process, which takes as thematic layers the  rock permeability, the rainfall, the drainage density,  the terrain slope, and the normalized difference vegetation index. Thus,  the Groundwater Potential Index is obtained, which is used to map potential areas for groundwater exploration. The resulting map is compared with the existing data of the water point inventory, generated by the Ecuador’s National Institute of Meteorology and Hydrology. Data validation by this method shows that 30% of the water points are located in areas not suitable for groundwater exploration, while 70% are in favorable areas.</p>

scholarly journals Estimación de zonas potenciales de aguas subterráneas en la cuenca del río Portoviejo mediante análisis jerárquico basado en SIG y teledetección

2021 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Jorge Patricio Chonlong Alcivar ◽  
Henry Antonio Pacheco Gil
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Groundwater Potential ◽  
Free Access ◽  
Gis And Remote Sensing ◽  
Potential Index ◽  
El Sistema ◽  
Potential Groundwater ◽  
Del Rio ◽  
Hydrogeological Information

  La utilización del agua subterránea en Ecuador se ha venido incrementando y cada día gana importancia debido al agotamiento, contaminación o inexistencia de fuentes superficiales. Sin embargo, la información hidrogeológica de la cual dispone el país es incompleta, desactualizada y dispersa, faltando implementar estrategias para la gestión del recurso hídrico subterráneo, iniciando con el proceso de legalización y regularización de los concesionarios formales e informales. El presente estudio tuvo como objetivo determinar las zonas potenciales de aguas subterráneas en la cuenca del río Portoviejo aplicando el método de análisis jerárquico (AHP, según sus siglas en inglés) basado en el sistema de información geográfica (SIG) y teledetección de acceso libre. A partir de este análisis se obtuvo el índice de potencial de aguas subterráneas (GWPI, según sus siglas en inglés), utilizado para la creación del mapa de zonas potenciales, el cual fue comparado con datos existentes en el inventario de puntos de agua. En la validación, se obtuvo una efectividad del 87 % para el mapa resultante, el cual ha sido influenciado en mayor grado por la permeabilidad de la roca, la precipitación y la densidad de drenajes, y en menor proporción por la pendiente del terreno y el índice de vegetación de diferencia normalizada (NDVI, según sus siglas en inglés).   Palabra clave: agua subterránea, AHP, GWPI.   Abstract The use of groundwater in Ecuador has been increasing and is gaining importance every day due to the depletion, contamination, or non-existence of surface sources. However, the hydrogeological information available in the country is incomplete, outdated, and dispersed, and there is a lack of strategies for managing subway water resources, starting with the process of legalization and regularization of formal and informal concessionaires. The objective of this study was to determine the potential groundwater areas in the Portoviejo River basin by applying the hierarchical analysis method (AHP) based on geographic information system (GIS) and remote sensing with free access. From this analysis, the groundwater potential index (GWPI) was obtained, used to create the map of potential areas, which was compared with existing data in the inventory of water points. In the validation, effectiveness of 87 % was obtained for the resulting map, which has been influenced in greater degree by the permeability of the rock, the precipitation and the density of drainages, and in smaller proportion by the slope of the land and the normalized difference vegetation index (NDVI).  Keywords: AHP, groundwater, GWPI.

scholarly journals Identification of Groundwater Potential Zones Using GIS and Multi-Criteria Decision-Making Techniques: A Case Study Upper Coruh River Basin (NE Turkey)

2021 ◽  
Vol 10 (6) ◽  
pp. 396
Author(s):  
Ümit Yıldırım
Keyword(s):  
Drainage Density ◽  
Groundwater Potential ◽  
High Potential ◽  
Groundwater Potential Zones ◽  
Topographic Wetness Index ◽  
Analytic Hierarchy ◽  
Soil Thickness ◽  
Çoruh River Basin ◽  
Basin Area ◽  
Very High

In this study, geographic information system (GIS)-based, analytic hierarchy process (AHP) techniques were used to identify groundwater potential zones to provide insight to decisionmakers and local authorities for present and future planning. Ten different geo-environmental factors, such as slope, topographic wetness index, geomorphology, drainage density, lithology, lineament density, rainfall, soil type, soil thickness, and land-use classes were selected as the decision criteria, and related GIS tools were used for creating, analysing and standardising the layers. The final groundwater potential zones map was delineated, using the weighted linear combination (WLC) aggregation method. The map was spatially classified into very high potential, high potential, moderate potential, low potential, and very low potential. The results showed that 21.5% of the basin area is characterised by high to very high groundwater potential. In comparison, the very low to low groundwater potential occupies 57.15%, and the moderate groundwater potential covers 21.4% of the basin area. Finally, the GWPZs map was investigated to validate the model, using discharges and depth to groundwater data related to 22 wells scattered over the basin. The validation results showed that GWPZs classes strongly overlap with the well discharges and groundwater depth located in the given area.

Assessment and Modeling of Groundwater Potential Zones by using Geospatial and Decision-making approaches: A case study in Anantapur district, Andhra Pradesh, India

2021 ◽  
Vol 5 (1) ◽  
pp. 34-44
Author(s):  
B. Pradeep Kumar ◽  
K. Raghu Babu ◽  
M. Rajasekhar ◽  
M. Ramachandra
Keyword(s):  
Andhra Pradesh ◽  
Primary Source ◽  
Drainage Density ◽  
Groundwater Potential ◽  
Groundwater Exploration ◽  
Groundwater Potential Zone ◽  
Potential Zone ◽  
Groundwater Potential Zones ◽  
Thematic Layers ◽  
Total Study Area

Freshwater scarcity is a major issue in Rayalaseema region in Andhra Pradesh (India). Groundwater is the primary source of drinking and irrigation water in Anantapur district, Andhra Pradesh, India. Therefore, it is important to identify areas having groundwater potential; however, the current methods of groundwater exploration consume a lot of time and money. Analytic Hierarchy Process (AHP)-based spatial model is used to identify groundwater potential zones in Anantapur using remote sensing and GIS-based decision support system. Thematic layers considered in this study were geology, geomorphology, soils, land use land cover (LULC), lineament density (LD), drainage density (DD), slope, and rainfall. According to Saaty’s AHP, all these themes and individual features were weighted according to their relative importance in groundwater occurrence. Thematic layers were finally combined using ArcGIS to prepare a groundwater potential zone map. The high weighted value area was considered a groundwater prospecting region. Accordingly, the GWPZ map was classified into four categories: very good, good, moderate, and poor. The very good GWPZ area is 77.37 km2 (24.93%) of the total study area. The northeastern and southeastern sections of the study area, as well as some medium patches in the center and western regions, are covered by moderate GWPZs, which cover an area of 53.07 km2 (17.10%). However, the GWP in the study area’s central, southwestern, and northern portions is poor, encompassing an area of approximately 79.31 km2 (25.56%). Finally, RS and GIS techniques are highly effective and useful for identifying GWPZs.

scholarly journals Spatial analysis of damaged vegetation in the Mianyuan River basin after the Wenchuan Earthquake

2015 ◽  
Vol 3 (5) ◽  
pp. 3225-3250
Author(s):  
H. Z. Zhang ◽  
J. R. Fan ◽  
X. M. Wang ◽  
T. H. Chi ◽  
L. Peng
Keyword(s):  
Slope Stability ◽  
Wenchuan Earthquake ◽  
River Basin ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Probabilistic Approach ◽  
Model Development ◽  
Slope Aspect ◽  
2008 Wenchuan Earthquake ◽  
Elevation Model

Abstract. The 2008 Wenchuan earthquake destroyed large areas of vegetation. Presently, these areas of damaged vegetation are at various stages of recovery. In this study, we present a probabilistic approach for slope stability analysis that quantitatively relates data on earthquake-damaged vegetation with slope stability in a given river basin. The Mianyuan River basin was selected for model development, and earthquake-damaged vegetation and post-earthquake recovery conditions were identified via the normalized difference vegetation index (NDVI), from multi-temporal (2001–2014) remote sensing images. DSAL (digital elevation model, slope, aspect, and lithology) spatial zonation was applied to characterize the survival environments of vegetation, which were used to discern the relationships between successful vegetation regrowth and environmental conditions. Finally, the slope stability susceptibility model was trained through multivariate analysis of earthquake-damaged vegetation and its controlling factors (i.e. topographic environments and material properties). Application to the Subao River basin validated the proposed model, showing that most of the damaged vegetation areas have high susceptibility levels (88.1% > susceptibility level 3, and 61.5% > level 4). Our modelling approach may also be valuable for use in other regions prone to landslide hazards.

Mapping of Groundwater potential zones in Lingasugur Taluk in North-eastern part of Karnataka, India using Remote Sensing, GIS and multi-criteria data analysis

2021 ◽  
Vol 14 (12) ◽  
pp. 13-22
Author(s):  
Ajgaonkar Swanand ◽  
S. Manjunatha
Keyword(s):  
Remote Sensing ◽  
Groundwater Resources ◽  
Drainage Density ◽  
Groundwater Potential ◽  
Groundwater Exploration ◽  
Geographical Information ◽  
Groundwater Potential Zones ◽  
Thematic Maps ◽  
North Eastern

Groundwater research has evolved tremendously as presently it is the need of society. Remote Sensing (RS) and Geographical Information System (GIS) are the main methods in finding the potential zones for the groundwater. They help in assessing, exploring, monitoring and conserving groundwater resources. A case study was conducted to find the groundwater potential zones in Lingasugur taluk, Raichur District, Karnataka State, India. Ten thematic maps were prepared for the study area such as geology, hydrogeomorphology, land use/ land cover, soil type, NDVI, NDWI, slope map, lineament density, rainfall and drainage density. A weighted overlay superimposed method was used after converting all the thematic maps in raster format. Thus from analysis, the classes in groundwater potential were made as very good, moderate, poor and very poor zones covering an area of 10.1 sq.km., 169.25 sq.km., 1732.31 sq.km. and 53.66 sq.km. respectively. By taking the present study into consideration, the future plans for urbanization, recharge structures and groundwater exploration sites can be decided.

THE NORMALIZED DIFFERENCE VEGETATION INDEX AS AN INDICATOR OF DYNAMICS

2021 ◽  
Author(s):  
Haddad Amar ◽  
Beldjazia Amina ◽  
Kadi Zahia ◽  
Redjaimia Lilia ◽  
Rached-Kanouni Malika
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Climatic Factors ◽  
Mediterranean Ecosystems ◽  
Point Of View ◽  
Aleppo Pine ◽  
Landsat 8 ◽  
North East ◽  
The North ◽  
Pine Trees

Mediterranean ecosystems are considered particularly sensitive to climate change. Any change in climatic factors affects the structure and functioning of these ecosystems and has an influence on plant productivity. The main objective of this work is to characterize one of the Mediterranean ecosystems; the Chettaba forest massif (located in the North-East of Algeria) from a vegetation point of view and their link with monthly variations using Landsat 8 satellite images from five different dates (June 25, 2017, July 27, 2017, August 28, 2017, October 15, 2017). The comparison of NDVI values in Aleppo pine trees was performed using analysis of variance and the use of Friedman's non-parametric test. The Mann-Kendall statistical method was applied to the monthly distribution of NDVI values to detect any trends in the data over the study period. The statistical results of NDVI of Aleppo pine trees indicate that the maximum value is recorded in the month of June, while the lowest values are observed in the month of August where the species studied is exposed to periods of thermal stress.

scholarly journals Deserted Medieval Village Reconstruction Using Applied Geosciences

2020 ◽  
Vol 12 (12) ◽  
pp. 1975
Author(s):  
Alexandru Hegyi ◽  
Apostolos Sarris ◽  
Florin Curta ◽  
Cristian Floca ◽  
Sorin Forțiu ◽  
...  
Keyword(s):  
High Resolution ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Vegetation Indices ◽  
Archaeological Site ◽  
Point Of View ◽  
Surface Model ◽  
Small Satellites ◽  
High Resolution Images ◽  
Remote Sensing Techniques

This study presents a new way to reconstruct the extent of medieval archaeological sites by using approaches from the field of geoinformatics. Hence, we propose a combined use of non-invasive methodologies which are used for the first time to study a medieval village in Romania. The focus here will be on ground-based and satellite remote-sensing techniques. The method relies on computing vegetation indices (proxies), which have been utilized for archaeological site detection in order to detect the layout of a deserted medieval town located in southwestern Romania. The data were produced by a group of small satellites (3U CubeSats) dispatched by Planet Labs which delivered high-resolution images of the Earth’s surface. The globe is encompassed by more than 150 satellites (dimensions: 10 × 10 × 30 cm) which catch different images for the same area at moderately short intervals at a spatial resolution of 3–4 m. The four-band Planet Scope satellite images were employed to calculate a number of vegetation indices such as NDVI (Normalized Difference Vegetation Index), DVI (Difference Vegetation Index), SR (Simple Vegetation Ratio) and others. For better precision, structure from motion (SfM) techniques were applied to generate a high-resolution orthomosaic and a digital surface model in which the boundaries of the medieval village of “Șanțul Turcilor” in Mașloc, Romania, can be plainly observed. Additionally, this study contrasts the outcomes with a geophysical survey that was attempted inside the central part of the medieval settlement. The technical results of this study also provide strong evidence from an historical point of view: the first documented case of village systematization during the medieval period within Eastern Europe (particularly Romania) found through geoscientific methods.

scholarly journals Generating annual estimates of forest fire disturbance in Canada: the National Burned Area Composite

2020 ◽  
Vol 29 (10) ◽  
pp. 878 ◽  
Author(s):  
R. J. Hall ◽  
R. S. Skakun ◽  
J. M. Metsaranta ◽  
R. Landry ◽  
R.H. Fraser ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Landsat Imagery ◽  
Fire Disturbance ◽  
Automated System ◽  
Primary Data ◽  
Burned Area ◽  
Average Accuracy ◽  
Mapping System

Determining burned area in Canada across fire management agencies is challenging because of different mapping scales and methods. The inconsistent removal of unburned islands and water features from within burned polygon perimeters further complicates the problem. To improve the determination of burned area, the Canada Centre for Mapping and Earth Observation and the Canadian Forest Service developed the National Burned Area Composite (NBAC). The primary data sources for this tool are an automated system to derive fire polygons from 30-m Landsat imagery (Multi-Acquisition Fire Mapping System) and high-quality agency polygons delineated from imagery with spatial resolution ≤30m. For fires not mapped by these sources, the Hotspot and Normalized Difference Vegetation Index Differencing Synergy method was used with 250–1000-m satellite data. From 2004 to 2016, the National Burned Area Composite reported an average of 2.26 Mha burned annually, with considerable interannual variability. Independent assessment of Multi-Acquisition Fire Mapping System polygons achieved an average accuracy of 96% relative to burned-area data with high spatial resolution. Confidence intervals for national area burned statistics averaged±4.3%, suggesting that NBAC contributes relatively little uncertainty to current estimates of the carbon balance of Canada’s forests.

scholarly journals Spatial Downscaling of GPM Annual and Monthly Precipitation Using Regression-Based Algorithms in a Mountainous Area

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Chesheng Zhan ◽  
Jian Han ◽  
Shi Hu ◽  
Liangmeizi Liu ◽  
Yuxuan Dong
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Mountainous Area ◽  
Monthly Precipitation ◽  
Practical Applications ◽  
Precipitation Measurement ◽  
Digital Elevation ◽  
Elevation Model ◽  
Global Precipitation ◽  
Spatial Downscaling

As a fundamental component in material and energy circulation, precipitation with high resolution and accuracy is of great significance for hydrological, meteorological, and ecological studies. Since satellite measured precipitation is often too coarse for practical applications, it is essential to develop spatial downscaling algorithms. In this study, we investigated two downscaling algorithms based on the Multiple Linear Regression (MLR) and the Geographically Weighted Regression (GWR), respectively. They were employed to downscale annual and monthly precipitation obtained from the Global Precipitation Measurement (GPM) Mission in Hengduan Mountains, Southwestern China, from 10 km × 10 km to 1 km × 1 km. Ground observations were then used to validate the accuracy of downscaled precipitation. The results showed that (1) GWR performed much better than MLR to regress precipitation on Normalized Difference Vegetation Index (NDVI) and Digital Elevation Model (DEM); (2) coefficients of GWR models showed strong spatial nonstationarity, but the spatial mean standardized coefficients were very similar to standardized coefficients of MLR in terms of intra-annual patterns: generally NDVI was positively related to precipitation when monthly precipitation was under 166 mm; DEM was negatively related to precipitation, especially in wet months like July and August; contribution of DEM to precipitation was greater than that of NDVI; (3) residuals’ correction was indispensable for the MLR-based algorithm but should be removed from the GWR-based algorithm; (4) the GWR-based algorithm rather than the MLR-based algorithm produced more accurate precipitation than original GPM precipitation. These results indicated that GWR is a promising method in satellite precipitation downscaling researches and needed to be further studied.

scholarly journals Selecting Inter-city Transportation Routes in Complex Terrains Using Quantitative Methods – A Case Study from Northern Yunnan, China

2020 ◽  
Vol 32 (2) ◽  
pp. 269-277
Author(s):  
Jisheng Xia ◽  
Pinliang Dong ◽  
Zhifang Zhao
Keyword(s):  
Quantitative Methods ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Route Selection ◽  
Analytic Hierarchy ◽  
Suitability Evaluation ◽  
Grey Relational ◽  
Transportation Routes ◽  
Hierarchy Process

A variety of factors are involved in inter-city transportation route selection in the areas of complex terrain. With the help of Geographic Information System (GIS), three quantitative methods were employed to determine the transport routes between 44 cities in Northern Yunnan (China), an area with alpine valleys, Karst mountains, and plateau basins. The network analysis in GIS was used to find the routes based on the Transport Suitability Evaluation (TSE) map, which was produced from several factors, including population density, terrain slope, vertical terrain dissection, landslide and mud-flock area, land cover types, and Normalized Difference Vegetation Index (NDVI). Analytic Hierarchy Process (AHP), Grey Relational Analysis (GRA), and Delphi analysis were used to collect and calculate suitability values of these factors. Finally, all the routes connecting 44 cities of Northern Yunnan formed a network which could provide reference for route selection planning in the area.  

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