The purpose of this study is to evaluate changes in the land cover in the southeastern section of the central higlands of Madagascar. Landsat imagery, TM and ETM+, have been analyzed and classified according to the major land cover types. Two multi-temporal datasets are compared for change detection between the year 1994 and 1999. Due to the steep mountainous terrain of the surrounding region, evaluation data have been used to assist with visual interpretation of land cover types. The analytical outputs of this study will consist of 2 thematic maps that classify the major land types (1994 and 1999), a change detection image, shaded relief, and a 3-D terrain map of the selected area of interest. This study provides valuable information about the fragile nature of this area and other areas with similar characteristics, quantitative results regarding the amount of landscape change, and insight into the need for subsequent studies.

One of the most polluted areas in Alexandria coastal water is El-Mex Bay, which receive more than 90% of Alexandria domestic waster, in addition to agricultural and industrial wastes. There is, therefore, an urgent need to monitor these outfall areas to ensure that there is an acceptable degree of dispersion and dilution of sewage at sites of both existing and proposed outfalls. Historical data from hydrological observations and meteorological records were used to simulate the water circulation in the El-Mex bay. While current observations and satellite images were used to validate the model. The numerical simulation was performed by the Princeton ocean model (POM) with a resolution of about 0.125 minute (about 200 m in X-direction and 255 m in Y- direction). To test the sensitivity of the model simulation. The results were compared with current measurements taken in the same period. The comparison showed good agreement between the observed and simulated current. The results of the model simulation were discussed in the light of the indications in the light of the indications form satellite images taken at different periods for El-Mex region. The results show that the main sewage water impact area varies to great extends depending on the outlet location, the weather conditions and discharge rate. In general, the huge amount of polluted water discharged in El-Mex Bay via El-Umoum drain were distributed along the coasts of Alexandria during the predominate westerly wind regime. While, the Northerly and north easterly winds caused an accumulation of waste water inside the bay.

In this paper, a proposed system for tracing water body edges has been designed and implemented based on modifying Canny’s edge detector. This modification is based on the insertion of procedural rules having the characteristics of water, which is the feature to be exclusively distinguished. The spectral characteristics of the extracted water feature in different recorded wavelength bands have been used in the designed rules. This work consists of four stages. The first is detecting boundaries between objects suing Canny’s method which extracts all possible boundaries in the image representing all features governed by the selected thresholds. The second is developing a set of rules to remove all edges except those of the pertinent selected feature (water body). In this step, the process depends on prior information about the pattern of spectral response of water (reflectance values) in the selected Landsat-TM bands 2, 4 and 7. The third stage is developing and applying a thinning technique based on the edge direction information. In the fourth stage, a tracing process has been developed, which includes rules designed for connecting relevant edges. Such rules have considered the following parameters; the terminals of each edge distance between edges and the directionality of each edges. This procedure has been applied to Landsat satellite –TM data of a test sample image containing an open area of River Nile and its branches forming islands, demonstrating the condition of changing the tracing direction. Results of applying the proposed system have been successful in automatically delineating the main river stream features.

The red Sea coastal zone is characterized by the presence of highly sensitive and fragile biological natural resources and habitats. Due to the unplanned touristic activities, the Red Sea coastal zone is subjected to a serious environmental deterioration, El-Gona coastal area is located at the northern part of the Red Sea western coast. It is characterized by an extensive tidal flat and mangrove forest, and important extensive coral reefs and seagrass mats host its aquatic environment. Also, it is characterized by a wide coastal plain and sabkha habitat. This harmonious natural setting has been dramatically deteriorated and some were demolished due to the extensive construction works of El-Gona resort LANDSAT-TM scenes before and after touristic development are used for the execution of this study . They are used to detect, analyze and assess the environmental deterioration due to the rapid and unplanned touristic development Land use / land cover maps produced from multi –date (1984 and 1998) LANDSAT data. Different changes of the environmentally sensitive habitats and natural resources are detected. Also, the various anthropogenic features are interpreted from a recent high-resolution satellite image (IKONOS) . The GIS tool is used to integrate the results of the applied digital image processing techniques and the field measurement data, with different digital maps such as those depicting topography and geology, to assess the environmental deterioration in the study area. Results indicate a serious deterioration on different land-use /land –cover classes of the study. The total area of the changed land-use / land cover classes from 1984 to 1998 is calculated by (7.16) km2. The changed areas are concentrated around the shoreline. The reef flat, coastal sabkha and coral reef ecosystems are the most affected and deteriorated natural resources and habitats at the study area , Also, the anthropogenic modifications in the reef flat, in terms of landfill and excavation , may lead to increase of the erosion processes in and nearby El-Gona Shoreline .Recommendations are indicated that the environmental legislations must be enforced and Environmental Sensitivity. Index maps should be produced for the entire Egyptian coastal zones.