Horizontal and vertical positional accuracy assement of cartographic products of the amazon region derived from interferometric sar data in X and P bands from ORBISAR sensor / Avaliação da acurácia posicional planialtimétrica de produtos cartográficos da Região Amazônica extraídos de dados SAR interferométricos nas bandas X e P do sensor ORBISAR

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

21/11/2011

RESUMO

The Geographic Service of the Brazilian Army (DSG) is running a major mapping project in Brazil, called ´´Radiography Amazon", the region known as ´´Empty Mapping the Amazon." This area, approximately 1,8 million km$^2$, has not had, to date, appropriate land information mapping at scales larger than 1:250,000, except insufficient cartographic documents at the level of the tops of trees and not at ground level. In this project are being used Interferometric Synthetic Aperture Radars and Polarimetric (PolInSAR) for airborne imaging bands X and P, and thus are able to make the nearly 20,000 map products at scales of 1:50,000 and 1:10,0000. In order to carry out the assessment of positional accuracy, this study was based on the comparison between the coordinates and altitudes obtained in the field and the products processed by OrbiSat and derived from X and P band from OrbiSar sensor, considering the land use and slope as possible factors that can affect the quality of the imaging. The study area is located in the municipality of São Gabriel da Cachoeira-AM, was divided into regions of homogeneous physical characteristics (strata) and the assessment of cartographic products was performed using the results of statistical tests. In these conditions this work is original. To collect the samples it was employed trackers geodetic dual-frequency methods for positioning and differential combined with the total station to the forest areas. For planimetric analysis 105 points were collected identifiable in the orthoimage band X and meticulously pre-selected. Of these only 42 were identified unambiguously in the P-band orthoimage. This sample showed geometric distortions (deviations) of approximately 14.36 m and 54 cm in the north and east, and the standard error of 0.39 that would meet the 1:50,000 (Class A) and 1:25,000 (Classes B and C), as Cartographic Accuracy Standard. Once removed the bias the result will be 1:25,000 (Classes A, B and C). For the analysis of the altimetric Digital Terrain Model (P-band) were collected 1047 points in 14 strata. The analysis of strata resulting from the interaction of classes of slope gradient and land use and soil showed that the greatest errors of underestimation occur mainly at the intersection of the strata slope gradient \textit {ondulated} and \textit{mountains} with layers of land use and Exposed soil. On the other hand, overestimation of the biggest errors are in the strata \textit{ondulated-forest} and \textit{mountainous-forest}, and higher dispersion in the strata \textit{mountainous-pastures}, \textit{mountain-regeneration}, \textit{mountainous-forest}. Thus, according toBrazilian cartographic standards, the result of analysis on DTM (Digital Terrain Model) considering the proportion of each stratum in this study presented absolute error of 8.17 m, meeting the scale 1:50,000 for all classes. As a final result, cartographic products would be classified on the scale 1:50,000 for Classes A, B or C.

ASSUNTO(S)

radar de abertura sintética (sar) modelo digital do terreno (mdt) ortoimagem interferometria orbisar avaliação cartográfica synthetic aperture radar (sar) digital terrain model (dtm) orthoimage interferometry orbisar cartograhy assessment

ACESSO AO ARTIGO

Documentos Relacionados