Gulcan Sarp

Spectral and spatial quality analysis of pan-sharpening algorithms: A case study in Istanbul

Abstract In this paper, the performance of four different image pan-sharpening methods, the Brovey the Gram-Schmidt (GS), the Intensity-Hue-Saturation (IHS) and the Principle Component Analysis (PCA), are investigated based on spectral and spatial distortions. In the study, the Brovey, the GS, the IHS, and the PCA pan-sharpening algorithms are applied to multispectral (MS) bands of Ikonos and QuickBird images. The spectral and spatial qualities of pan- sharpened images are tested using the Correlation Coefficient (CC), the Root Mean Square Error (RMSE), and the Structural Similarity Index (SSIM). A comparative performance analysis of the CC, the RMSE, and the SSIM shows that the PCA followed by the GS, the Brovey, and the IHS perform the best among all the techniques, except a swap in the PCA and the GS in the SSIM.

Water body extraction and change detection using time series: A case study of Lake Burdur, Turkey

Abstract In this study, spatiotemporal changes in Lake Burdur from 1987 to 2011 were evaluated using multi-temporal Landsat TM and ETM+ images. Support Vector Machine (SVM) classification and spectral water indexing, including the Normalized Difference Water Index (NDWI), Modified NDWI (MNDWI) and Automated Water Extraction Index (AWEI), were used for extraction of surface water from image data. The spectral and spatial performance of each classifier was compared using Pearsons r, the Structural Similarity Index Measure (SSIM) and the Root Mean Square Error (RMSE). The accuracies of the SVM and satellite-derived indexes were tested using the RMSE. Overall, SVM followed by the MNDWI, NDWI and AWEI yielded the best result among all the techniques in terms of their spectral and spatial quality.

Activity level of tectonic basins, western section of the North Anatolian Fault Zone, Turkey

We employed quantitative techniques to investigate tectonic activity levels and development stages of the Bolu, Yenicaga, Dortdivan, Cerkes, Ilgaz, and Tosya structural basins along the western portions of the main trace of the North Anatolian Fault Zone (NAFZ). Our methodology incorporates six morphometric indices: basin shape (basin elongation and compactness), hypsometric integral, mountain-front sinuosity, stream length gradient index, valley floor width-to-height ratio, and asymmetry factor, obtained from the digital elevation model of the region generated from 1/25,000-scale topographic maps. These indices are integrated within the framework of an analytical hierarchy process to provide relative activity level values of the individual basins. The new analyses indicate that the basins have contrasting tectonic activity characteristics. Judging from the applied indices, the relative increasing order of the tectonic basin activity is Dortdivan, Cerkes, Yenicaga, Ilgaz, Tosya, and Bolu. Among the basins located to the north of the NAFZ, the activity decreases eastwards, whereas to the south of this profound fault zone, it decreases towards the west.

Spatial analysis of morphometric indices: the case of Bolu pull-apart basin, western section of North Anatolian Fault System, Turkey

Advances in quality, acquisition and processing of high-resolution digital topography over the past decade have enabled geomorphologists to interpret topography in terms of tectonic processes in a quantitative and more objective way. This study defines the tectonic impact of the North Anatolian fault system (NAFS) on the evaluation and activity of the Bolu pull-apart basin using morphometric indices based on topographic maps. In this study, three different indices including valley floor width to height ratio (Vf), asymmetry factor (Af), and Stream Length Gradient Index (SL) are applied to the tectonic basin area. To detect the deviation from spatial randomness of applied indices, the weighted correlation coefficient Moran’s I is used, and results are interpreted at 99% confidence interval. According to the results, the tectonic impact of NAFS on the northern and western sides of the basin distinctly differs from one another. Clustered distribution of Vf and Af values on the southern side of the basin margin reveals that this side of the basin margin is tectonically more deformed compared with the northern side. The applied methodology reveals that the spatial analysis of the morphometric indices proved to be the effective tool in analyzing tectonic influence of the fault system on the opposite side of the basin margins.

An approach for detection of buildings and changes in buildings using orthophotos and point clouds: A case study of Van Erriş earthquake

Abstract This paper presents an image analysis of the Van Erciş earthquake, and demonstrates how efficiently the orthophoto images and point clouds from stereo matching data can be used for automatic detection of buildings and changes in buildings. The proposed method contains three basic steps. The first step is to classify the high-resolution pre and post event Red- Green-Blue (RGB) orthophoto images (orthoRGB) using Support Vector Machine (SVM) classification procedure to extract the building areas. In the second step, normalized Digital Surface Model (nDSM) band derived from point clouds and Digital Terrain Model (DTM) is integrated with the SVM classification (nDSM+orthoRGB). In the last step, building damage assessment is performed through a comparison between two independent classification results from pre-and post-event data. It was observed that using the nDSM band in the classification process as additional bands the accuracy of classification increases significantly.

Evaluation of sustainable water supply alternatives in karstified rock masses using GIS and AHP methodology for Antalya (Turkey) urban area

The demand for water by growing populations and agricultural operations in the Antalya urban area is expected to increase significantly in the near future. For that reason, alternative water sources are important to the future of Antalya. There are a large number of water sources around Antalya to meet the water needs of the city. These are classified as surface water, groundwater, and reclaimed water. One of the options considered is the provision of water from rock pores. Rock pore water has been adopted as a potential alternative for water resources in the area. It is proposed to drill horizontal galleries using the microtunnel machine to the rock masses in carbonate aquifers to obtain new water resources. This study presents a useful method to find water supply alternatives for urban areas like Antalya. In this study, karstified rock masses have been evaluated for the karst hydrosystems and water source from rock pores using geographic information systems and analytical hierarchy process. Additionally, this study discusses the practical value of the provision of water from rock pores, as well as the possibility of application and selection of potential areas.