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ABSTRACT
The relief, as genetic factor and "support" on which the grassland areas are engrafted on, may be equally considered the major decisive element for vegetation's type, aspect and consistency, through altitude, slope and orientation. This study will highlight the influence exerted on grassland areas by relief factors, in mountain and sub-mountain regions, and subsequently it will determine the differentiated landscaping "norms" in concordance with the singularity of each analyzed sector. The grassland assessment will rely on the calculation of the Normalized Difference Vegetation Index (NDVI). According to the Digital Elevation Model (DEM), and also to the observations and measurements in field, we will determine the altitude intervals and the characteristic parametres, achieving a NDVI value flooring. The values obtained will be quantitatively and qualitatively analyzed with Geographical Informatic Systems (GIS) and remote sensing techniques, to capture the changes that occur with changing environmental conditions. Since the researches are carried out in mountainous and hills regions, grasslands, as non-homogenous spatial entities, may present significant differences and therefore it is important to respect their defining elements, during landscaping and exploitation, in concordance with the physical-geographical particularities of each sub-area.
Keywords: evaluation index, remote sensing, spatial planning
INTRODUCTION
Successive to the processing of the satellite data, with the help of specific methods and means, we may obtain vegetation indices, whose values are materialized in images and other products that offer a „raw" measure of the vegetation, in quantitative and qualitative terms. Among the vegetation indices, the Normalized Difference Vegetation Index (NDVI) is at the moment one of the most frequent approaches for the solution of scientific issues linked to the vegetal cover. The achievement and processing of NDVI values supposes different methodologies and has different forms, according to the objective and complexity and analyses ([5], [1], [3]).
The relationship between the NDVI values and the relief characteristics (especially altitude and declivity), approached for different aspects, represents the main topic of numerous scientific paperworks, having a great theoretical and practical importance in the quantitative and qualitative vegetation assessment, and also of other components directly or indirectly influenced by this ([11], [6], [7], [9]). Under such circumstances, this study will highlight the influence exercised on grassland areas by relief factors, in mountainous and hills regions, and subsequently, according...