Evaluation of the quality of generated orthoimages from PRISM/ALOS-2: A case study for São Gabriel, Rio Grande do Sul, Brazil

Authors

  • Angela Akemi Goto Nakahori Universidade Federal do Rio Grande do Sul. Programa de Pós-Graduação em Sensoriamento Remoto e Meteorologia (CEPSRM). Av. Bento Gonçalves, 9500, C.P. 15044, 91501-970, Porto Alegre, RS, Brasil.
  • Sérgio Florêncio de Souza Universidade Federal do Rio Grande do Sul. Programa de Pós-Graduação em Sensoriamento Remoto e Meteorologia (CEPSRM). Av. Bento Gonçalves, 9500, C.P. 15044, 91501-970, Porto Alegre, RS, Brasil.

DOI:

https://doi.org/10.4013/gaea.2012.81.02

Abstract

The focus of this study was the generation and evaluation of ALOS/PRISM orthoimages using DEMs (Digital Elevation Models) derived from distinct combinations of sensor viewing from a 1B1 image processing level. The studied area chosen was a rural one located in São Gabriel municipality, in the State of Rio Grande do Sul, Brazil, which is nearly flat (average altimetry 160 m). In the first stage the DEMs were generated using a combination of the three viewing and control points obtained through field survey. Among other parameters, the minimum amount of control points needed that could generate the MDE, the processing level and the window size were tested. Next, two results were compared: the extraction with ASTER (GDEM) Digital Elevation Models and SRTM (Shuttle Radar Topographic Mission), which was generated from the Project TOPODATA from the National Institute for Space Research (INPE, 2009). Finally, the DEMs with the checkpoints were evaluated and the best DEMs for orthorectification were selected using statistical analysis. The results showed that for this specific study all DEMs combining views Backward-Forward generated from the control points would be approved, since they have the lowest values of RMS (Mean Square Error between 2.94 and 3m). Moreover, it was shown that when using DEMs from other combinations, the orthoimages obtained also comply with the Cartographic Accuracy Standard (PEC) for Class A scale 1:25,000 as well as the orthoimages generated from Global SRTM Elevation Models and GDEM. The flatness of the studied area seems to be the main reason for the good performance achieved by SRTM together with the PRISM generated DEMs.

Key words: ALOS/PRISM orthoimages, 1B1 processing level, Digital Elevation Models, orthorectification.

Downloads

Published

2013-07-30

Issue

Vol. 8 No. 1 (2012): jan/jun

Section

Artigos

License

I grant the journal Gæa – Journal of Geoscience the first publication of my article, licensed under Creative Commons Attribution license (which allows sharing of work, recognition of authorship and initial publication in this journal).

I confirm that my article is not being submitted to another publication and has not been published in its entirely on another journal. I take full responsibility for its originality and I will also claim responsibility for charges from claims by third parties concerning the authorship of the article.

I also agree that the manuscript will be submitted according to the journal’s publication rules described above.