VALIDATION POINTS

Foram geradas 85.152 amostras estratificadas aleatórias para validação dos mapas anuais de cobertura e uso da terra do Brasil do MapBiomas. As amostras foram inspecionadas visualmente utilizando imagens Landsat atribuindo a classe de uso e cobertura da terra para cada ano de 1985 a 2024.

DOWNLOAD THE VALIDATION POINT DATASET

O conjunto de amostras para a validação da Coleção 10 está sendo revisado e será disponibilizado em breve. Enquanto isso, os dados da Coleção 9 estão disponíveis para download nos seguintes formatos de arquivos csv, xlsx and shapefile. Each sample presents coordinates, biomes, declivity, municipality/UF and informations by year of: land cover and use classe in the column 'CLASS_'(código/ID da legenda used in the maps); interpreter agreement level in the column 'COUNT_'(3:maximum, 2:medium and 1:low) and edge pixel between two classes in the column 'BORDA_'(1:yes and 0:no). There are also the probability data and the sample weights.

UNDERSTAND HOW THE SAMPLES WERE COLLECTED

The stratification of the samples was done on two levels: by supercards (joining every four IBGE maps of 1:250,000) and by slope classes defined by EMBRAPA. Considering the minimum quantity of 500 points per supercharter and corrected with the Bonferroni equation. Dimensioned so as to ensure a maximum margin of error of 5% and confidence level of 95% in the smallest unit of geographical coverage, in other words, in each supercharter. For the national territory the maximum expected error was 0.5%

For the visual interpretation the TVI (Temporal Visual Inspection) platform was used, developed by Lapig, in which each pixel was initially interpreted by 3 independent analysts. Pixels for which there was no agreement between the assigned classes were re-inspected by supervisor and the pixel's class assigned.

In Collection 7, these points have been updated for the years 2019, 2020 and 2021 and, in the Collection 8, for the year of 2022, as well as adjusted for new legend classes.

For more information about the content description and sample method, access the ATBD. Another reference material on samples and reference points analysis are available in the article.

For questions, suggestions and other information please contact contato@mapbiomas.org and participate in the MapBiomas Forum.