Abstract: The paper presents a method for the semiautomated classification of the planation surfaces, using the Digital Terrain Model (DTM) and the object-oriented analysis. The effort undergone for developing such a method has a number of motivations. The first one is that these landforms are very important for decoding the geomorphologic evolution of the relief units. The second motivation concerns the fact that their identification and mapping, by using classical means, represents a difficult demarche, which requires a lot of time. Finally, the already-known limits of the relief analysis using the DTM at pixel level impose the testing of an object-oriented analysis, in which the area under study is divided into objects of various dimensions, as homogenous as possible from the viewpoint of one or more properties. The method that we propose supposes the following steps: the realisation of the slope model and of the flow model, starting from the DTM; the division, by segmentation into objects that are as homogenous as possible from the viewpoint of the slope; the classification of the objects into landforms (planation surfaces) by using the fuzzy functions and taking into account more factors simultaneously (the average slope value, the minimum slope value, the flow coefficient and the altitude), and the selection and grouping of the identified surfaces into sculptural complexes. The first stages represent the automated part of the method, while the last one requires a detailed geomorphologic analysis of the area, as well as the validation of the results on the field. The method was firstly developed for the Godeanu Mountains, the map of the levelled surfaces (Niculescu, 1965) being used for the identification of the parameters included in the algorithm, as well as for testing the results obtained in the view of the improvement of the method. Due to the good results thus obtained, the same method was also used for mapping the levelled surfaces in the Mehedinţi Mountains, and, along with the field observations, there was realised the planation surfaces map for this relief unit.
Abstract: The present paper aims at highlighting the urban development, fishing activities, tourism, industrial development and agricultural activities that affect delicate and valuable coastal ecosystems. A supervised classification, post-classification, change detection techniques were applied to Land sat images acquired in 1991 and 2007, respectively, to map land cover changes along the north-western coast of Egypt, from Alexandria to El Alamein. A supervised classification was carried out on the six reflective bands for the two images individually with the aid of true ground data. The truthful ground information, collected during field trips using ancillary data, visual interpretation and experts’ knowledge of the area using GIS, further refined the classification results. Post-classification change detection technique was used to produce image through cross-tabulation. Changes among different land cover classes were assessed. During the study period, a very severe land cover change has taken place as a result of agricultural and tourist development projects. These shoreline and land cover changes led to modifications of the environmental properties.
Abstract: A relief that is strongly modelled by extensive erosion processes (sheet erosion, rills and gullies) characterizes the Alpine level of the Bucegi Mountains. All processes are favoured by the geological structure represented by conglomerates, limestone with grit stone intrusions, by strongly degraded podzolic soils with a loamy-sandy texture in the first layer and by some economic activities, such as the overgrazing and the tourism. We have identified an area with large-scale erosion forms in the sector comprised between Furnica Peak and Piatra Arsa Peak. This paper analyses the genesis and the manifestation conditions of the erosion processes, as well as the climate, making use of the temperature and the precipitation data provided by the meteorological stations in the region. Using the Péltier diagram, we framed the region to various seasons. By subsequently using the Péguy diagram, we framed the region to the morphoclimatic conditions and to the river processes. On the other hand, by using GIS, we created geology, slope, soil and vegetation Boolean maps and then the risk map to the erosion processes.
Abstract: Geomorphosites stand for relief forms or geomorphologic processes that in time have gained an aesthetic, scientific, cultural, historical or economic value, as a result of human perception. Taking into consideration the above mentioned definition, the present paper aims at inventorying and evaluating part of the geomorphosites in the Bucegi Mountains. The final purpose is to propose some measures for a better protection and tourist promotion. The presence of numerous geomorphosites in the Bucegi Mountains is the direct result of the presence of limestones and conglomerates, as well as the succession of different modelling systems in time (glacial, periglacial, fluvial). We analysed this area since there are many and varied geomorphosites, and at the same time, it is one of the major tourist destinations (the largest number of tourists and the best tourist infrastructure within the Romanian Carpathian Mountains).
Abstract: The present study approaches a series of geomorphological aspects specific to hydrographic basins of small sizes which, in certain circumstances, favor the occurrence of floods having major effects upon the human settlements. We focused our attention on three neighboring hydrographical basins, located in a mountainous area in the north of the Romanian Carpathians, where on the 24th of July 2008, following some heavy rains, there occurred major floods. Although the three rivulets the Valea Seacă, the Izvorul Alb and the Valea Caselor are tributaries on the right side of the Moldova river, the behaved differently during the above mentioned flood. The particularity is that within the Izvorul Alb hydrographic basin the maximum flow during the flood was two time lower than in the case of the other two basins between which it is located. Given the fact that the quantity of precipitations received by all three basins did not differ and the physical-geographical features are similar, there was performed the morphometric analysis of all three hydrographical basins in order to outline the morphometric variables with a role in the concentration of the runoff: the surface, the slope, the roundness, the shape coefficient, etc. The conclusion drawn from this case study is that the asymmetry of the basin is an essential parameter in making the difference in respect to the behavior of small hydrographical basins during the formation of exceptional floods.