scholarly journals Analysis of Remotely Sensed Data for Mapping Land Cover Types by Applying a Maximum Likelihood Classifier Algorithm, in Al-Ahsaa Oasis, Eastern Region, Saudi Arabia

2018 ◽  
Author(s):  
Abdelrahim Salih
Keyword(s):  
Saudi Arabia ◽  
Maximum Likelihood ◽  
Land Cover ◽  
Accuracy Assessment ◽  
Sand Dunes ◽  
Bare Soil ◽  
Eastern Region ◽  
Remotely Sensed Data ◽  
Maximum Likelihood Classifier ◽  
Cover Class

Accurate, detailed and recent Information about land cover/use is important and much more needed for different aspects of sustainable development and environmental management. As remote sensing datasets are becomes one of the most important and effective tools to generate such information, this study aimed to generating land cover map for sub area in Al-Ahasaa Oasis, Saudi Arabia, by using and classifying a subset of Landsat-ETM+ image of the selected study area, as bases and required input for future studies and researches. Different image preprocessing techniques in addition to a will-known and widely used classification method (i.e., Maximum Likelihood classifier) were applied. To be reliable with the final product, accuracy assessment was carried out with 89% agreement and accepted according to the applied method. Different land cover classes were found in the study area, which includes (Sand dunes, Water bodies, Sabakha, Bare soil, Urban, and Agricultural lands). The study also revealed that the dominant land cover class is sand dunes with approximately ± 70% in area. The study strongly indicated that the area has long been affected by sand movement. Finally, the study suggested that, further researches with more advanced methods rather than traditional methods are needed in the future to support the findings of this study, with high degree of accuracy.

scholarly journals Integrated Geological, Hydrogeological, and Geophysical Investigations of a Barchan Sand Dune in the Eastern Region of Saudi Arabia

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 682
Author(s):  
Mohammed Benaafi ◽  
Sherif M. Hanafy ◽  
Abdullatif Al-Shuhail ◽  
Ammar El-Husseiny ◽  
Jack Dvorkin
Keyword(s):  
Grain Size ◽  
Saudi Arabia ◽  
Water Content ◽  
Sand Dune ◽  
Sand Dunes ◽  
Homogeneous Medium ◽  
Eastern Region ◽  
Large Area ◽  
Electrical Resistivity Survey ◽  
Dune Crest

In arid countries such as Saudi Arabia, aeolian sand often covers a large area of the country. Understanding the variations of sand properties in dunes, including grain size, sorting, mineral composition and water content, can be important for groundwater recharge, environmental, and construction applications. Earlier studies examined properties of sand dunes by collecting samples from the surface. This study aims to investigate variations of sand properties within a Barchan sand dune in the coastal area of Saudi Arabia, by collecting samples and measurements from two vertically drilled boreholes up to the ground water level; one drilled in the dune crest and another one in the limb. Representative samples were collected and analyzed for their texture parameters, water content, and mineralogy. Electrical resistivity survey data was also acquired to map water content variation in the dune limb, and for comparison with well bore data. The reported results show no vertical variations in grain size or sorting in the dune crest. In contrast, the upper 0.5 m of the dune limb shows a relatively poorer sorting than found in deeper parts of the dune. Laterally, no variations in minerology were observed between crest and limb sands while grain size tended to be slightly coarser in the dune limb compared to the crest. Regarding the water content, it was found to vary vertically, probably due to previous cycles of rainfall infiltration through the sand body. Such observed variation in water content is consistent with the measured resistivity profile which could clearly identify the water table and areas with higher water content. This study concludes that beyond the upper 0.5 m, the Barchan sand dune body can be treated as a homogeneous medium in terms of mineralogy and sorting while grain size increases slightly toward the limb side.

scholarly journals An Investigation on Land Cover Mapping Capability of Classical and Fuzzy based Maximum Likelihood Classifiers

2018 ◽  
Vol 7 (2) ◽  
pp. 939 ◽  
Author(s):  
Shivakumar B R ◽  
Rajashekararadhya S V
Keyword(s):  
Maximum Likelihood ◽  
Land Cover ◽  
Classification Accuracy ◽  
Distance Measure ◽  
Accuracy Assessment ◽  
Sensor Data ◽  
Remote Sensor ◽  
Mixed Pixels ◽  
Overlapping Classes

In the past two decades, a significant amount of research has been conducted in the area of information extraction from heterogeneous remotely sensed (RS) datasets. However, it is arduous to exactly predict the behaviour of the classification technique employed due to issues such as the type of the dataset, resolution of the imagery, the presence of mixed pixels, and spectrally overlapping of classes. In this paper, land cover classification of the heterogeneous dataset using classical and Fuzzy based Maximum Likelihood Classifiers (MLC) is presented and compared. Three decision parameters and their significance in pixel assignment is illustrated. The presented Fuzzy based MLC uses a weighted inverse distance measure for defuzzification process. 10 pixels were randomly selected from the study area to illustrate pixel assignment for both the classifiers. The study aims at enhancing the classification accuracy of heterogeneous multispectral remote sensor data characterized by spectrally overlapping classes and mixed pixels. The study additionally aims at obtaining classification results with a confidence level of 95% with ±4% error margin. Classification success rate was analysed using accuracy assessment. Fuzzy based MLC produced significantly higher classification accuracy as compared to classical MLC. The conducted research achieves the expected classification accuracy and proves to be a valuable technique for classification of heterogeneous RS multispectral imagery. 

scholarly journals LAND USE AND LAND COVER CLASSIFICATION OF SENTINEL 2-A: ST PETERSBURG CASE STUDY

2019 ◽  
Vol XLII-1/W2 ◽  
pp. 13-16 ◽  
Author(s):  
M. Cavur ◽  
H. S. Duzgun ◽  
S. Kemec ◽  
D. C. Demirkan
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Accuracy Assessment ◽  
Ground Truth ◽  
Remotely Sensed Data ◽  
Vector Machines ◽  
Kappa Value ◽  
Sentinel 2

<p><strong>Abstract.</strong> Land use and land cover (LULC) maps in many areas have been used by companies, government offices, municipalities, and ministries. Accurate classification for LULC using remotely sensed data requires State of Art classification methods. The SNAP free software and ArcGIS Desktop were used for analysis and report. In this study, the optical Sentinel-2 images were used. In order to analyze the data, an object-oriented method was applied: Supported Vector Machines (SVM). An accuracy assessment is also applied to the classified results based on the ground truth points or known reference pixels. The overall classification accuracy of 83,64% with the kappa value of 0.802 was achieved using SVM. The study indicated that of SVM algorithms, the proposed framework on Sentinel-2 imagery results is satisfactory for LULC maps.</p>

scholarly journals Detection of Changes in Land Use/ Land Cover Using Remote Sensing and GIS Techniques in Area East of the Nile Khartoum State-Sudan

2018 ◽  
Vol 10 (2) ◽  
pp. 12
Author(s):  
Babiker, E.M.A ◽  
Ibrahim, M.M ◽  
Elhag, A.M.H ◽  
Nser, S.H ◽  
Elsheikh, M.A ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Land Use ◽  
Land Cover ◽  
Sandy Soil ◽  
Sand Dunes ◽  
Unsupervised Classification ◽  
Bare Soil ◽  
Water Bodies ◽  
Sand Sheet ◽  
Remote Sensing Techniques

<p>The study area lies to the east of the Nile (Sharg Elneel), Khartoum State (latitudes 15<sup>o</sup> 25̎ 1̍ and 16° 19̎ 1̍ N and longitudes 33° 19̎ 8̍ and 33°02̎ 9̍ E). Using remote sensing techniques and geographic information system (GIS), the changes in land cover/land use have been estimated using two methods: supervised and unsupervised classification. the images were those of the years 1973, 2001, and 2015 MSS, ETM, ETM+, respectively(173/49 &amp; 173/48 path/ row). The study area was classified into the following nine LU/LC types: water bodies, vegetation, rocky area, sandy soil, sandy sheet, clayey soil, bare soil, sand dunes and settlement areas. The individual areas covered by each type of land use/ land cover were calculated for each image using supervised and unsupervised classification. Then the areas were compared among the different years (images). The results indicated a decrease in areas of sandy soil, water bodies, vegetation cover, sand dunes, clay soil, and bare soil for years 1973-2001 and 1973-2015.  That was associated with significant increase in settlement area, sand sheet for the same period. As for the period 2001 and 2015 was an increase in the areas of vegetation, sandy soil, dunes, clay soil, and settlement. While there was a decrease in water bodies, rocky area, sand sheet and bar soil. A striking result of his study was an increase of 50% in the settlement area for the period 1973 – 2015. This indicated that more drift of people towards the Capital took place during this period possibly due to drought and civil strife. Also people come to Khartoum to have better living conditions, education, health care and to work and may be they look at Khartoum as a spring board for going abroad. This study recommended the use of remote sensing techniques and geographic information system in the follow up of desertification and land degradation by following changes in land cover and land use. It also recommended that sand movement (sand encroachment) shall be retarded possibly through increasing vegetation cover through seed broadcasting of pasture and range plants during the rainy season and to exploit the ground water of the NSS aquifer for irrigation.</p>

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