Análise da dinâmica espacial do ecossistema manguezal com abordagem metodológica orientada a objeto

Abstract

To the knowledge of the spatial dynamics of mangrove areas of estuarine complex on the west coast of Ceará were used satellite images with spatial resolution of 30m and images colored with a resolution of 2m, with application of remote sensing technology and geographic information systems (GIS). The sensor images of LANDSAT TM 5, observed for a period of 23 years, and orthophotos that cover the area object, classification procedures were applied object-oriented technique that reflects the state of the art for extracting spatial information. The object-oriented approach delimits natural and homogeneous bodies from the spectral information of pixels, and features related to geometry and topology of objects. This algorithm was developed for classification of images with high spatial resolution, where no spectral mixing: the pixels have similar characteristics to their neighbors, while images of low and medium spatial resolution, pixels contain spectral information corresponding to multiple objects. Although the theoretical / conceptual classification method with object orientation prioritize applications on images of high spatial resolution, the research aimed to develop studies on images of medium spatial resolution for quantification of areas occupied by vegetation mangrove estuaries Coast West Ceara, between the years 1985 and 2008. With results of object-oriented classification, produced in medium spatial resolution images were analyzed with the spatial dynamics of the area occupied by the system mangrove along the established time frame. The analysis of the spatial dynamics between the 1st and 2nd periods recorded an increase corresponding to the percentage change of 3.43%, and the interval between the 2nd and 3rd periods was recorded variation of 6.35%. However, the variation observed between the values of mangrove areas between the 1st and 3rd periods, corresponding to the time frame from 1985 to 2008, the rate recorded is around 10%. Complementing the established objectives, studies were concentrated on the acquisition of relative values to quantify with accuracy, the vegetation of the mangrove ecosystem, but obtained on high-resolution orthorectified images, for comparison with data published in works of other authors, drawn up techniques and different methodologies employed in the research. For validating the classification results were the same used orthophotos, obtained in 2007, as a reference for verifying the Truth Road, with a view to ensuring the quality of geometric and positional features of mangrove forests identified. Emphasize that the results showed discrepancies acceptable to the established objectives. Finally, the discrepancies observed in the values for the complex estuarine surveyed, compared with other published works are associated with different methodologies and techniques employed.