Detection and Delineation of Water Bodies in Hilly Region using CartoDEM SRTM and ASTER GDEM Data

2017 ◽  
Vol 1 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Sainath Aher ◽  
Komali Kantamaneni ◽  
Pragati Deshmukh
Keyword(s):  
Nearest Neighbor ◽  
Assessment Tool ◽  
Rapid Assessment ◽  
Water Bodies ◽  
Western Ghat ◽  
Landsat 8 ◽  
Srtm Dem ◽  
Resources Management ◽  
Aster Gdem ◽  
Hilly Region

Detection and delineation of Water Body Area (WBA), particularly over inaccessible hilly region is not always possible in view of time, resources and cost issues. An automated procedure for detection and delineation of water bodies in the hilly region was performed using satellite-derived DEMs. CartoDEM, SRTM and ASTER GDEM data with 30, 90 and 30 m resolutions, respectively to generate the Elevation Points Features (EPF) in GIS platform. Total 7194906 EPFs were generated using these three DEMs. Contour and slope maps were also prepared to eliminate the outlier EPFs (non-water bodies) with flattered surface logic. Flattened area on DEMs, connected contour at edges of water bodies and 0° to 0.5° slopping area were considered as WBA in the region (2311 Km2) of Western Ghat (India). The nearest neighbor to cubic convolution conversion of DEMs was found useful for detection of boundary of water bodies more precisely. These results were validated from Landsat-8 satellite images and topographic maps (Survey of India). About 3.09% from CartoDEM, 2.22% area from ASTER GDEM and 4.38% from SRTM DEM were estimated as WBA. CartoDEM data can be suggested for precise detection of smaller water bodies in hilly region. Methodology formulated in this study could be used as a rapid assessment tool for detection of water bodies, especially in the inaccessible region for better water resources management.

Impact of LULC Changes on LST in Rajshahi District of Bangladesh: A Remote Sensing Approach

2020 ◽  
Vol 3 (1) ◽  
pp. 11-23 ◽  
Author(s):  
Abdulla Al Kafy ◽  
Abdullah Al-Faisal ◽  
Mohammad Mahmudul Hasan ◽  
Md. Soumik Sikdar ◽  
Mohammad Hasib Hasan Khan ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Surface Temperature ◽  
Land Surface ◽  
Agricultural Land ◽  
Global Climate ◽  
Urban Expansion ◽  
Water Bodies ◽  
Landsat 8 ◽  
Lulc Changes ◽  
The Impact

Urbanization has been contributing more in global climate warming, with more than 50% of the population living in cities. Rapid population growth and change in land use / land cover (LULC) are closely linked. The transformation of LULC due to rapid urban expansion significantly affects the functions of biodiversity and ecosystems, as well as local and regional climates. Improper planning and uncontrolled management of LULC changes profoundly contribute to the rise of urban land surface temperature (LST). This study evaluates the impact of LULC changes on LST for 1997, 2007 and 2017 in the Rajshahi district (Bangladesh) using multi-temporal and multi-spectral Landsat 8 OLI and Landsat 5 TM satellite data sets. The analysis of LULC changes exposed a remarkable increase in the built-up areas and a significant decrease in the vegetation and agricultural land. The built-up area was increased almost double in last 20 years in the study area. The distribution of changes in LST shows that built-up areas recorded the highest temperature followed by bare land, vegetation and agricultural land and water bodies. The LULC-LST profiles also revealed the highest temperature in built-up areas and the lowest temperature in water bodies. In the last 20 years, LST was increased about 13ºC. The study demonstrates decrease in vegetation cover and increase in non-evaporating surfaces with significantly increases the surface temperature in the study area. Remote-sensing techniques were found one of the suitable techniques for rapid analysis of urban expansions and to identify the impact of urbanization on LST.

scholarly journals Monitoring the Spatial Variation of Aerosol Optical Depth and Its Correlation with Land Use/Land Cover in Wuhan, China: A Perspective of Urban Planning

2021 ◽  
Vol 18 (3) ◽  
pp. 1132
Author(s):  
Qijiao Xie ◽  
Qi Sun
Keyword(s):  
Land Use ◽  
Air Quality ◽  
Urban Planning ◽  
Land Cover ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Water Bodies ◽  
Landsat 8 ◽  
Land Use Land Cover ◽  
The Impact

Aerosols significantly affect environmental conditions, air quality, and public health locally, regionally, and globally. Examining the impact of land use/land cover (LULC) on aerosol optical depth (AOD) helps to understand how human activities influence air quality and develop suitable solutions. The Landsat 8 image and Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol products in summer in 2018 were used in LULC classification and AOD retrieval in this study. Spatial statistics and correlation analysis about the relationship between LULC and AOD were performed to examine the impact of LULC on AOD in summer in Wuhan, China. Results indicate that the AOD distribution expressed an obvious “basin effect” in urban development areas: higher AOD values concentrated in water bodies with lower terrain, which were surrounded by the high buildings or mountains with lower AOD values. The AOD values were negatively correlated with the vegetated areas while positively correlated to water bodies and construction lands. The impact of LULC on AOD varied with different contexts in all cases, showing a “context effect”. The regression correlations among the normalized difference vegetation index (NDVI), normalized difference built-up index (NDBI), normalized difference water index (NDWI), and AOD in given landscape contexts were much stronger than those throughout the whole study area. These findings provide sound evidence for urban planning, land use management and air quality improvement.

scholarly journals Comparing of Landsat 8 and Sentinel 2A using Water Extraction Indexes over Volta River

2017 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
Clement Kwang ◽  
Edward Matthew Osei Jnr ◽  
Adwoa Sarpong Amoah
Keyword(s):  
Remote Sensing ◽  
Satellite Images ◽  
Remote Sensing Data ◽  
Unsupervised Classification ◽  
Water Bodies ◽  
Water Extraction ◽  
Landsat 8 ◽  
Sensing Data ◽  
Optimal Classifier ◽  
Sentinel 2A

Remote sensing data are most often used in water bodies’ extraction studies and the type of remote sensing data used also play a crucial role on the accuracy of the extracted water features. The performance of the proposed water indexes among the various satellite images is not well documented in literature. The proposed water indexes were initially developed with a particular type of data and with advancement and introduction of new satellite images especially Landsat 8 and Sentinel, therefore the need to test the level of performance of these water indexes as new image datasets emerged. Landsat 8 and Sentinel 2A image of part Volta River was used. The water indexes were performed and then ISODATA unsupervised classification was done. The overall accuracy and kappa coefficient values range from 98.0% to 99.8% and 0.94 to 0.98 respectively. Most of water bodies enhancement indexes work better on Sentinel 2A than on Landsat 8. Among the Landsat based water bodies enhancement ISODATA unsupervised classification, the modified normalized water difference index (MNDWI) and normalized water difference index (NDWI) were the best classifier while for Sentinel 2A, the MNDWI and the automatic water extraction index (AWEI_nsh) were the optimal classifier. The least performed classifier for both Landsat 8 and Sentinel 2A was the automatic water extraction index (AWEI_sh). The modified normalized water difference index (MNDWI) has proved to be the universal water bodies enhancement index because of its performance on both the Landsat 8 and Sentinel 2A image.

scholarly journals How objective are protected area management effectiveness assessments? A case study from the iSimangaliso Wetland Park

Koedoe ◽  
2013 ◽  
Vol 55 (1) ◽  
Author(s):  
Clinton Carbutt ◽  
Peter S. Goodman
Keyword(s):  
Peer Review ◽  
Protected Area ◽  
Best Practice ◽  
Assessment Tool ◽  
Rapid Assessment ◽  
Operating Conditions ◽  
Protected Area Management ◽  
Management Effectiveness ◽  
Effectiveness Assessment ◽  
Area Management

The assessment of protected area management effectiveness was developed out of a genuine desire to improve the way protected areas are managed and reported on, in relation to a formalised set of conservation objectives. For monitoring and reporting purposes, a number of participatory methods of rapidly assessing management effectiveness were developed. Most rapid assessment methods rely on scoring a range of protected area-related activities against an objective set of criteria documented in a formal questionnaire. This study evaluated the results of two applications of the same management effectiveness assessment tool applied to the same protected area, namely the iSimangaliso Wetland Park, South Africa. The manner in which the assessments were undertaken differed considerably and, not unexpectedly, so did the results, with the national assessment scoring significantly higher than the provincial assessment. Therefore, a further aim was to evaluate the operating conditions applied to each assessment, with a view to determining which assessment was more closely aligned with best practice and hence which score was more credible. The application of the tool differed mainly with respect to the level of spatial detail entered into for the evaluation, the depth and breadth of the management hierarchy that was consulted, the time in which the assessment was undertaken and the degree of peer review applied. Disparate scores such as those obtained in the assessments documented here are likely to bring the discipline of management effectiveness assessment into disrepute unless an acceptable and standardised set of operating procedures is developed and adopted. Recommendations for such a set of ‘indispensable constants’ were made in this article to ensure that management effectiveness assessments remain robust and reputable, thereby ensuring an honest picture of what is happening on the ground. Conservation implications: We proposed that standard operating procedures should be in place when protected area management effectiveness assessments are undertaken, in order for the results to be credible. This involves ensuring that the right people participate and that each participant is allowed sufficient time to peer review each other.

scholarly journals Análisis de componentes biofísicos del balance de radiación neta, usando teledetección, en la cuenca hidrográfica de Sorocaba con bosque atlántico intervenido, Brasil

2021 ◽  
Author(s):  
Argemiro José Moreno Arteaga ◽  
Manoel Mariano Neto da Silva ◽  
Gabriel Vidal Mota ◽  
Salmi Lizzeth Tapia Aguirre ◽  
Bernardo Barbosa da Silva
Keyword(s):  
Landsat 8 ◽  
Aster Gdem ◽  
América Del Sur

Los ecosistemas forestales, como el bosque atlántico en América del sur, han sido removidos para dar lugar a actividades agropecuarias y asentamiento humanos. Tal situación estaría ocasionando cambios en la absorción de la energía solar en la superficie terrestre, lo que modifica el consumo de radiación neta, que, a su vez, puede influir en la temperatura del aire. Por consiguiente, esta investigación tuvo como objetivo evaluar las alteraciones de la radiación neta en la cuenca hidrográfica de Sorocaba, para analizar cómo el cambio de bosque atlántico por áreas agropecuarias y construcciones antrópicas impacta en la radiación neta y la repercusión que podría estar ocasionando en la regulación del clima local. Para esto fue determinado el balance de radiación en la cuenca y sus componentes biofísicos (NDVI, temperatura superficial, albedo y radiación emitida), por medio del modelo SEBAL, utilizando imágenes OLI/TIRS–Landsat 8 y ASTER(GDEM). Los resultados revelaron que las zonas construidas, seguidas por las agropecuarias, en comparación con la de bosque atlántico, presentan valores de albedo y temperatura superficial superiores, y, consecuentemente, mayores flujos de calor emitido a la atmósfera en forma de radiación infrarroja. Por consiguiente, se generó menores consumo de radiación neta, cuya media para las áreas boscosas, agrícolas, con pastos, suelos desnudos y construidas fue de 712,40Wm-2, 669,40Wm-2, 629,90Wm-2, 616,60Wm-2 y 524,40Wm-2, respectivamente. Así, la deforestación en la cuenca ocasionó que disminuyera la radiación neta y se emita más calor a la atmósfera, lo que favorece el efecto invernadero (principal causante del calentamiento global), en detrimento de poder regular la temperatura del aire.

scholarly journals Combining Multi-Sensor Satellite Imagery to Improve Long-Term Monitoring of Temporary Surface Water Bodies in the Senegal River Floodplain

2020 ◽  
Vol 12 (19) ◽  
pp. 3157
Author(s):  
Andrew Ogilvie ◽  
Jean-Christophe Poussin ◽  
Jean-Claude Bader ◽  
Finda Bayo ◽  
Ansoumana Bodian ◽  
...  
Keyword(s):  
Surface Water ◽  
Water Bodies ◽  
Landsat 8 ◽  
Site Specific ◽  
Senegal River ◽  
Landsat 7 ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Sentinel 2

Accurate monitoring of surface water bodies is essential in numerous hydrological and agricultural applications. Combining imagery from multiple sensors can improve long-term monitoring; however, the benefits derived from each sensor and the methods to automate long-term water mapping must be better understood across varying periods and in heterogeneous water environments. All available observations from Landsat 7, Landsat 8, Sentinel-2 and MODIS over 1999–2019 are processed in Google Earth Engines to evaluate and compare the benefits of single and multi-sensor approaches in long-term water monitoring of temporary water bodies, against extensive ground truth data from the Senegal River floodplain. Otsu automatic thresholding is compared with default thresholds and site-specific calibrated thresholds to improve Modified Normalized Difference Water Index (MNDWI) classification accuracy. Otsu thresholding leads to the lowest Root Mean Squared Error (RMSE) and high overall accuracies on selected Sentinel-2 and Landsat 8 images, but performance declines when applied to long-term monitoring compared to default or site-specific thresholds. On MODIS imagery, calibrated thresholds are crucial to improve classification in heterogeneous water environments, and results highlight excellent accuracies even in small (19 km2) water bodies despite the 500 m spatial resolution. Over 1999–2019, MODIS observations reduce average daily RMSE by 48% compared to the full Landsat 7 and 8 archive and by 51% compared to the published Global Surface Water datasets. Results reveal the need to integrate coarser MODIS observations in regional and global long-term surface water datasets, to accurately capture flood dynamics, overlooked by the full Landsat time series before 2013. From 2013, the Landsat 7 and Landsat 8 constellation becomes sufficient, and integrating MODIS observations degrades performance marginally. Combining Landsat and Sentinel-2 yields modest improvements after 2015. These results have important implications to guide the development of multi-sensor products and for applications across large wetlands and floodplains.

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