scholarly journals SPATIO-TEMPORAL ASSESSMENT OF MARGALLA HILLS FOREST BY USING LANDSAT IMAGERY FOR YEAR 2000 AND 2018

Author(s):  
R. Batool ◽  
K. Javaid

Environmental imbalance due to human activities has shown serious threat to ecosystem and produced negative impacts. The main goal of this study is to identify, monitor and classify temporal changes of forest cover, build up and open spaces in Margalla Hills National Park, Islamabad. Geographic Information Sciences (GISc) and Remote Sensing (RS) techniques has been used for the assessment of analysis. LANDSAT-7 Enhanced Thematic Mapper (ETM+) and LANDSAT-8 Operational Land Imager (OLI) were utilized for obtaining data of year 2000 and 2018. Temporal changes were evaluated after applying supervised classification and discrimination was analyzed by Per-Pixel based change detection. Results depicts forest cover decrease from 87 % to 74 % whereas build up has increased from 5 % to 7 % over the span. Consequences also justify the presence of open land in study area that has been increased from 2 % to 7 % respectively.

2017 ◽  
Vol 3 (2) ◽  
pp. 204
Author(s):  
I Nengah Jaya Nugraha ◽  
I Wayan Gede Astawa Karang ◽  
I Gusti Bagus Sila Dharma

Erosion and abrasion are the events that led to the beach shoreline position changes. The impact of climate change is the rise in sea level also causes changes in the coastline. South East coast of Bali, especially along the coast Gianyar and Klungkung changing coastline. This study aims to identify and calculate the rate of shoreline change in Gianyar and Klungkung from 1995 to 2015. The study was a preliminary information shoreline change and do not analyze the causes such as tides, currents, waves, and wind. The method used remote sensing analysis with the extraction of the coastline from the Landsat 5 satellite images in 1995, Landsat 7 in 2005, and Landsat 8 2015. Landsat imagery analyzed by a combination of methods approach the threshold and band ratio of wave infrared and green. Image processing using software Quantum GIS 2.8 and System for Automated Geoscientific Analyses (SAGA) GIS 2.2, extention Digintal Shoreline Analysis System (DSAS) to make calculations transect coastline. The results of the analysis of overlaying identify coastline in Gianyar and Klungkung change at a rate that varies every village. The rate of change of coastline in Gianyar due to accretion between 0.5096 - 8.6074 m / yr, while due to erosion between -3.7343 to -1.3201 m / yr. The rate of change in Klungkung regency coastline due to accretion between 0.6337 - 2.6875 m / yr, while due to erosion between -8.8795 to -0.8833 m / yr.


2019 ◽  
Vol 11 (16) ◽  
pp. 1857 ◽  
Author(s):  
W. Dean Hively ◽  
Jacob Shermeyer ◽  
Brian T. Lamb ◽  
Craig T. Daughtry ◽  
Miguel Quemada ◽  
...  

A unique, multi-tiered approach was applied to map crop-residue cover on the Eastern Shore of the Chesapeake Bay, United States. Field measurements of crop-residue cover were used to calibrate residue mapping using shortwave infrared (SWIR) indices derived from WorldView-3 imagery for a 12-km × 12-km footprint. The resulting map was then used to calibrate and subsequently classify crop residue mapping using Landsat imagery at a larger spatial resolution and extent. This manuscript describes how the method was applied and presents results in the form of crop-residue cover maps, validation statistics, and quantification of conservation tillage implementation in the agricultural landscape. Overall accuracy for maps derived from Landsat 7 and Landsat 8 were comparable at roughly 92% (+/− 10%). Tillage class-specific accuracy was also strong and ranged from 75% to 99%. The approach, which employed a 12-band image stack of six tillage spectral indices and six individual Landsat bands, was shown to be adaptable to variable soil-moisture conditions—under dry conditions (Landsat 7, 14 May 2015) the majority of predictive power was attributed to SWIR indices, and under wet conditions (Landsat 8, 22 May 2015) single band reflectance values were more effective at explaining variability in residue cover. Summary statistics of resulting tillage class occurrence matched closely with conservation tillage implementation totals reported by Maryland and Delaware to the Chesapeake Bay Program. This hybrid method combining WorldView-3 and Landsat imagery sources shows promise for monitoring progress in the adoption of conservation tillage practices and for describing crop-residue outcomes associated with a variety of agricultural management practices.


Nativa ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 437
Author(s):  
Ayrton Machado ◽  
Ana Paula Marques Martins ◽  
Carlos Roberto Sanquetta ◽  
Ana Paula Dalla Corte ◽  
Jaime Wojciechowski ◽  
...  

A Mata Atlântica é reconhecida internacionalmente como uma das maiores e mais importantes florestas tropicais do continente sul-americano e além de sua importância para a biodiversidade, esse Bioma exerce importante função no ciclo de carbono. O objetivo deste trabalho foi desenvolver e aplicar uma rotina de detecção de mudanças dos estoques de volume, biomassa e carbono de 2000 a 2015 na Bacia do Rio Iguaçu, Estado do Paraná. Foram utilizadas imagens Landsat-7 ETM+ para o ano 2000 e Landsat-8 OLI para o ano de 2015 totalizando dez cenas para cada período. Foi desenvolvido uma rotina em Python e implementado no Software ArcGIS 10.4 para realizar a automatização de um processo de cálculo de estimativa de volume, biomassa e carbono para os remanescentes de vegetação natural. Houve acréscimo de 15,21% em volume, 14,95% em biomassa, 14,96% em carbono não considerando os estágios sucessionais nem subdivisão por fitofisionomia na bacia do Rio Iguaçu.  Desta forma, concluiu-se que a região de estudo está colaborando de forma positiva para a remoção de dióxido de carbono da atmosfera.Palavras-chave: bacia do rio Iguaçu; mudanças climáticas; sequestro de carbono. DYNAMICS OF VOLUME, BIOMASS AND CARBON IN THE ATLANTIC FOREST BY A CHANGE DETECTION TOOL ABSTRACT: The Atlantic Forest is recognized internationally as one of the largest and most important tropical forests in the South American continent and besides its importance for biodiversity, this biome plays important role in the carbon cycle. The objective of this work was to develop and apply a routine of detection of changes in volume, biomass and carbon stocks from 2000 to 2015 in the Iguaçu River Basin, State of Paraná. They were used Landsat-7 ETM+ images for the year 2000 and Landsat-8 OLI images for the year 2015 totaling ten images for each period. A routine was developed in Python and implemented in ArcGIS 10.4 Software to perform the automation of a calculation process of volume, biomass and carbon estimation for the remnants of natural vegetation. There was an increase of 15.21% in volume, 14.95% in biomass, 14.96% in carbon, not considering successional stages nor subdivision by phytophysiognomy in the Iguaçu River basin. Thus concludes that the region of study is collaborating in a positive way for the removal of carbon dioxide from the atmosphere.Keywords: Iguaçu river basin; climate changes; carbon sequestration.


2021 ◽  
Vol 16 (3) ◽  
Author(s):  
Rajeev Shankhwar ◽  
Rajlakshmi Datta ◽  
Navendra Uniyal

Dehradun city is the capital of Uttarakhand state of India. Evidence from the past research and literature [e.g. CDP 2007, Singh et al 2013, Gupta et al 2014] shows that in the late 80s, Dehradun city was much greener compared to the present condition. In the current study, we tried to identify the correlation between land surface temperature (LST) with Forest cover density classes (FCDC) and built-up area with open land. The current study reveals that there is a relationship between FCDC and LST in the study area. The range of LST recorded is between 32.07 to 43.99 °C. Among all the classes, minimum LST record in VDF class is 32.07°C and maximum LST record in built-up area 43.99°C. The present study shows the importance of vegetation cover in urban areas to reduce LST, air temperature and maintain the urban microclimate as well as to help reduce air pollution.


2021 ◽  
Vol 11 (4) ◽  
pp. 4258-4277
Author(s):  
Samawia Rizwan ◽  
Dr. Khalid Mahmood ◽  
Dr. Sajid Rashid Ahmad ◽  
Dr. Shafiq Ur Rehman

Wetlands are one of the most important and rich eco system. Deh akro II wetland complex is unique inland type of wetlands comprise of 35 wetlands in middle of Nara desert on bank of Nara Canal. They face a lot of degradation because of anthropogenic activities in the surrounding areas and lack of rainfall in last 2 decades. Chotiari wetland complex located in south east of Deh akro II wetland complex, it comprises of several fresh water lakes converted into reservoir in year 2003 for better irrigation purposes. This conversion of wetlands into reservoir does not did very well for surrounding agricultural lands and natural vegetation. So in this study two technique of Fractional cover mapping were used to classify three types of land covers in both study areas. Temporal analysis was performed using the Landsat 7 ETM+ image of year 2000 and Landsat 8 OLI image of year 2018. For better results NDVI, EVI and NDWI were also calculated. For Deh akro II wetland complex Kappa accuracy statistics for year 2000 is 84% and for year 2018 its 87%. Several changes were recorded in this time span of 18 years as 42% of water bodies area has been decreased, 48% of Agriculture area has been increased and 68% of natural vegetation area has been increased. Increase in amount of vegetation and agriculture indicates that with better management and planning, effects of climate change over the area can be minimized. Kappa accuracy statistics for Chotiari Wetland complex for year 2000 is 71% and for year 2018 it’s 73%. Enormous changes were noted in 18 years as Agriculture area has been decreased up to 91%, water area has been increased up to 15% and vegetation has unluckily decreased up to 98% in reservoir area. This huge decrease in Agriculture and natural vegetation is an alarming situation for the wildlife and native population as well as authorities of Chotiari wetland complex.


2016 ◽  
Vol 17 (1-2) ◽  
pp. 22-30
Author(s):  
S. G. Chornyy ◽  
D. A. Abramov

For rational use of soils it is necessary to possess exact information on soil properties. The traditional methods of monitoring of soils and (or) their separate properties based on local, one-time supervision don’t give an adequate assessment of a current state of a soil cover it should be noted. Transition to spatio-temporal methods with use of modern geoinformation and space technologies is necessary. Remote satellite methods of soil monitoring gain fast distribution, owing to the efficiency, a certain objectivism and relative low cost now, and also because of unique opportunities of one-time coverage by the images received from big height, enough territories, big on the area. For the development of remote monitoring chernozems southern used materials of multispectral scanning multispectral camera ETM + ( «Enhanced Thematic Mapper Plus»), which is on board the satellite «Landsat-7» (data of 2006, 2010, 2012) and OLI («Operational Land Imager»), which is on board the satellite «Landsat-8»(data 2015). The information obtained from them is unified from the point of view of preservation of geometry, calibration, a covering, spectral characteristics, quality of the image and availability of data, despite various carriers of devices ETM+ and OLI. The composite image which has been received from three cloudless satellite images of spring of 2012 (three terms of shooting – 21.04, 30.04, 05.05) has allowed to make the correlation analysis of extent of influence of maintenance of organic matter in a layer of soil of 0–10 cm at a brightness with various spectral channels of the camera ETM+. Such analysis has shown that the closest connection exists between the content of soil organic matter and brightness of the second (green), the third (red) and the fourth (the neighbor infrared) spectral channels. From them three, the greatest value of correlation has dependence between the content of soil organic matter (humus) and brightness of the red spectral channel (r=-0,32). For the purpose of spatio-temporal interpretation of the equation of multiple regressions, 20 agro landscapes in different parts of the Right-bank steppe of Ukraine (The Mykolayiv district and Zhovtnevy district of the Mykolayiv oblast) have been selected. For each agro landscapes was defined content of soil organic matter in the soil using Landsat 7 satellite images taken in 2006 and in 2010 and Landsat images 8 for 2015. The made estimates of maintenance of soil organic matter have shown on processes of fast loss of humus in all layers of soil. Annual losses of soil organic matter in a layer of 0–10 cm from 2006 for 2015 have made 0,16 % in a year, in a layer of 0–50 cm of about 0,13 % in a year, and in a layer of 0–100 cm at 0,10 % in a year. The irrational structure of sown areas and distribution of wind and water erosion processes is the reason of this sad process.


2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Yulius Yulius ◽  
T A Tanto ◽  
M Ramdhan ◽  
A Putra ◽  
H L Salim

ABSTRACT Bungus district of Kabung Bay is a growing region located at coastal zone of southern city of Padang, west sumatra. As a growing region, the Bungus district brings some impacts on population increase and degradation of environment quality. Therefore, it is needed an effort to identify land use changes and the distribution of land use in this region from the year of 2003 until 2013. This research used landsat 7 imagery in 2003 and landsat 8 imagery in 2013. The data were analysed descriptively using geographical informastion system. The result showd that (1) swamp land cover experienced the smallest land use change between 2003 until 2013 (0.02 ha/yr), meanwhile forest land use had the biggest change of about 224.8 ha/yr. The biggest addition of land cover belong to settlement area about 47.59 hectare, and the other hand occur on bush about -31.68 hectare. Keywords: Bungus district, landcover changes, Landsat imagery, GIS


2018 ◽  
Vol 10 (12) ◽  
pp. 4489 ◽  
Author(s):  
Yaowen Xie ◽  
Qiang Bie ◽  
Hui Lu ◽  
Lei He

In recent decades, the oases in the Hexi Corridor have gone through a tremendous transformation, which has caused a series of social and environmental problems. We aim to explore quantitatively the characteristics of the oasis expansion and their dynamic mechanism(s) in the Hexi Corridor, and their implications and impact on current and future policies. The spatial distribution pattern and dynamic changes experienced by the oases are examined using Landsat imagery. Their spatio-temporal changes are analyzed using the grid-transformed model and the dynamic-degree model. The model drivers are analyzed based on data from statistics yearbooks and field surveys. The total area of oases in the Hexi Corridor has expanded tremendously during the last 30 years from 10,709 km2 to 14,950 km2, almost 40% of the original value. Oasis evolution patterns of ‘unchanged’, ‘expanding’, ‘shrinking’, and ‘oscillating’ are observed at different periods in the three basins. In terms of area, almost half of the oases experienced some change, where most of the changes took place in the ecotone between oases and deserts, and the interior of oases due to the reclamation of abandoned land. Oasis expansion is mainly determined by the human instincts for survival and well-being, which are generally governed by population growth, agricultural policies and economic development. These changes reflect the need to find a balance in the relationship between ecological protection and increasing the well-being of local residents, because unreasonable or excessive development and utilization will cause damage to the local ecological environment.


2021 ◽  
Vol 13 (10) ◽  
pp. 1961
Author(s):  
Florent Lombard ◽  
Julien Andrieu

The mangrove areas in Senegal have fluctuated considerably over the last few decades, and it is therefore important to monitor the evolution of forest cover in order to orient and optimise forestry policies. This study presents a method for mapping plant formations to monitor and study changes in zonation within the mangroves of Senegal. Using Landsat ETM+ and Landsat 8 OLI images merged to a 15-m resolution with a pansharpening method, a processing chain that combines an OBIA approach and linear spectral unmixing was developed to detect changes in mangrove zonation through a diachronic analysis. The accuracy of the discriminations was evaluated with kappa indices, which were 0.8 for the Saloum delta and 0.83 for the Casamance estuary. Over the last 20 years, the mangroves of Senegal have increased in surface area. However, the dynamics of zonation differ between the two main mangrove hydrosystems of Senegal. In Casamance, a colonisation process is underway. In the Saloum, Rhizophora mangle is undergoing a process of densification in mangroves and appears to reproduce well in both regions. Furthermore, this study confirms, on a regional scale, observations in the literature noting the lack of Avicennia germinans reproduction on a local scale. In the long term, these regeneration gaps may prevent the mangrove from colonising the upper tidal zones in the Saloum. Therefore, it would be appropriate to redirect conservation policies towards reforestation efforts in the Saloum rather than in Casamance and to focus these actions on the perpetuation of Avicennia germinans rather than Rhizophora mangle, which has no difficulty in reproducing. From this perspective, it is necessary to gain a more in-depth understanding of the specific factors that promote the success of Avicennia germinans seeding.


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