IBGE releases today, June 26, 2014, ortho-rectified images of Piauí in its web portal. The images were obtained from the AVNIR-2 sensor of the ALOS satellite.

The ortho-rectified images are available in GeoTIFF format in the web page of IBGE through link

ftp://geoftp.ibge.gov.br/imagens_orbitais/ortoimagens/alos_avnir/

More information on this product can be obtained on link

ftp://geoftp.ibge.gov.br/imagens_orbitais/ortoimagens/Descritivo_Projeto_BC100_PI_situacao2014_abril_v1.pdf

Collection is part of BC100 project

The collection of available images is part of the "1:100,000 Cartographic Base - BC100" project, aimed at providing the society with ortho-rectified images, ortho-mosaics and image-maps of some Federation Units. The project is designed to address the demand for up-to-date information, compatible with the scale of 1:100,000 (1cm = 1km).

The ortho-rectified images underwent a correction process in relation to a number of geometric  distortions, caused by factors like image angle, relief, Earth curvature and Earth rotation.

Satellite images show 10 m of spatial resolution

The AVNIR-2 sensor produces images with 10-meter spatial resolution in four spectrum bands, corresponding to blue, green, red and near infrared. The images used in the project were acquired between 2006 and 2010, the majority of them in 2009 and 2010.