Delimitation geosystemic and modeling of environmental fragility as allowance for territorial management: a study of landscape cartography
ISBN 978-85-88783-11-9
Authors
1Moura Oliveira, J.H.; 2Chaves, J.M.
1UNIVERSIDADE ESTADUAL DE FEIRA DE SANTANA Email: jmouraoliveira8@gmail.com
2UNIVERSIDADE ESTADUAL DE FEIRA DE SANTANA Email: joselisamaria@gmail.com
Abstract
This study aimed to carry one geosystemic delimitation and analysis of environmental aiming to propose an integrated mapping of the landscape as an aid to management on part of Ecoregion Raso da Catarina Northeast of Bahia, Brazil. Initially, there was a theoretical and conceptual approach to issues that relate to the context of integrated studies and environmental cartography or mapping of landscapes. Later, described the methodological approach used in research, with emphasis on the geosystemic definition, analysis of the fragility of natural and anthropogenic environments with a view to mapping of landscapes via techniques of geographic information systems (GIS) as algebra simple maps and weighted overlay. The survey was conducted in a sector of the Brazilian semi-arid, high hardiness and uniqueness, relating to its environmental variables, such as lithology, relief (geomorphic processes), soils, climatic elements (precipitation, temperature, evaporation) and vegetation cover . It was also considered intervention undertaken by the federal or state government in an attempt to territorial and environmental planning in the region. To define geosystemic proposal used based on the geomorphological subdivision supported in geology maps, soil, vegetation, maps such as slope and hypsometry, besides the satellite image, the study area was mapped in twenty-four units. With the implementation of GIS analysis methodology of Fragility Natural and anthropogenic environments was achieved results consistent with the original proposal, which was established two forms of treatment variables. In order to adapt this methodology in GIS, we used the simple algebra (cumulative algebraic The analysis) and weighted overlay, respectively. The first evaluated the variables by crossing (sum operation) among morphometric categories (degrees dissection index), the class fragility soil and degrees of protection of vegetation, which still needed to proceed to the weighted average inference technique (IMP ) in order to prevent the occurrence of ambiguities resulting from the sum of the attributes of the classes. The result of this analysis was to map material, which consisted of five classes of fragility potential (Very Weak, Weak, Medium, Strong and Very Strong) and the dissection index as parameter determiner of the degree of fragility, and their levels depending on with the other variables (soil, vegetation cover / use and climate). The vegetation was classified as stable and unstable soils and determining the extent of weakness. The second method used the same variables having the form of differentiated integration, using the weighted overlay, that from the allocation of variables to weights and later overlay in a GIS environment. The cartogram result of this analysis described the area in four levels of fragility (Weak, Medium, Strong and Very Strong). The differentiation of the results between the two modeling can be explained due to the appreciation or determination given to relief variable (dissection index) as a parameter to characterize the degree of fragility in the first case. Whereas in modeling weighted overlap, there was an initial balance between the degrees of dissection variables (relief) and fragile soils in order to generate a relief-ground intermediate product. Finally, the proposed integrated mapping of the landscape as support for land management, it was possible to gather and synthesize, in a cartographic materials geosystemic units with the potential weaknesses of classes identified by weighted overlap. the different environmental variables (topography, soils and vegetation cover / use) with the potential fragility classes, in addition to engineering systems such as roads, transmission lines and polygons of this protected areas in the Study area.