Levantamento do meio físico do município de Araxá-MG,utilizando técnicas de geoprocessamento

by Brandão Rocha, Maria Beatriz

Abstract (Summary)
The twofold aim of this work was to survey the physical environment of the municipal districtof Araxá ? MG, using geoprocessing techniques, and to evaluate the evolution occurred inland use in two different periods: 1985 and 2005. Araxá is located in the Alto ParanaíbaMacrorregion in Minas Gerais State, between the geographic co-ordinates 19º25?53? -19°50?09? South latitude and Greenwich 46°44?27? - 47°13?38? West longitude. With an areaof 1,166.96km2 and 367km from the capital of Minas Gerais, the city had a population of78,997 inhabitants in 2000. In order to carry out this work, topographic charts,geomorphologic mapping and 1985 TM/Landsat 5 and 2005 CCD/CBERS satellite imageswere used. The survey of the physical environment was carried out based on the themes ofcontour, drainage and the district boundaries that made it possible to prepare the thematicmaps of the watersheds, slopes, hypsometry, geomorphology and land use (1985 and 2005).The thematic maps were elaborated using the IDRISI software, which also allowed evaluationof the areas, as well as the cross tabulation between the different thematic maps. From thedata analysis, one can verify that the district comprises 10 watersheds of which Ribeirão doInferno and Marmelo Watersheds are the larger, taking up approximately 42% the municipalarea. Slopes greater than 8%, those with relief varying from medially to strongly undulated,predominate the region. The degree of carving of the valley walls varies from weak to strongand drainage density varies from medium to low. Altitudes between 900 and 1200mpredominate. The data originated from the maps and tables allowed comparison and analysisof the evolution of land use in the two periods and evaluation of the adequacy of land useaccording to the physical environment. Ten categories of land use (Pivot, Urban and MixedUse, Rupestrian Field, Reforestation, Water Bodies, Farming, Mining, Forestry, Pasture andSavanna) were identified and mapped. In 2005, 46.22% of the area of the district wasoccupied by Pasture, followed by Rupestrian Fields (14.34%), Farming (16.12%) and Forest(15.49%). The other categories presented almost insignificant percentages. Within thistwenty-year period, Pasture area was reduced while Farming, Urban and Mixed Use,Reforestation and Mining areas increased. A reclassification was made for the final analysesof land use in Araxá, so that only two categories remained: natural vegetation and anthropicactivities. It was concluded that in terrains with high slopes, the larger areas are occupied bynatural vegetation, while in terrains with low slopes, anthropic activities occupied the largestarea. As for hypsometry, it is verified that in more elevated altitudes the natural vegetation(Rupestrian Field) predominates, and in lower altitudes anthropic activities predominate. TheRibeirão Marmelo Watershed is responsible for 48% of the farming area in the district; 68%of the Rupestrian Fields are located in the Ribeirão do Inferno Watershed; 98% of Miningareas are located in the Córrego do Sal, Ribeirão Capivara and Ribeirão Pirapetingawatersheds; 44% of the remaining Savanna is in the Córrego da Galinha Watershed; 42% ofForested area is located in the Ribeirão Capivara and Córrego Fundo watersheds.Geoprocessing has demonstrated itself as the best technique for achieving more accurate andreliable results. The interpretation of satellite images in different periods associated withother kinds of data (maps, laboratories and field) when integrated in a GIS, permits analysisand evaluation of the geographic space, providing important information to the municipaladministrators.
This document abstract is also available in Portuguese.
Bibliographical Information:

Advisor:Roberto Rosa; Ailton Luchiari; Jorge Luís Silva Brito

School:Universidade Federal de Uberlândia

School Location:Brazil

Source Type:Master's Thesis

Keywords:Geoprocessing Land use Remote sensing


Date of Publication:04/28/2006

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