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Summary of Proposal CAL0428

TitleGeostatistical accuracy assessment of elevation models derived from TerraSAR-X
Investigator Paredes Hernandez, Cutberto Uriel - University of Leicester, Department of Geography
Team Member
Dr. Tansey, Kevin J. - University of Leicester, Department of Geography
Dr. Tate, Nicholas J. - University of Leicester, Department of Geography
Prof. Fisher, Peter F. - University of Leicester, Department of Geography
Dr. Salinas Castillo, Wilver E. - Universidad Autónoma de Tamaulipas, UAM Agronomía y Ciencias
Summary

The main objectives of this research are

  • To assess the accuracy of elevation models derived from TerraSAR-X using a geostatistical framework (theory), and
  • To evaluate their fitness for use for selecting routes for new overhead transmission lines (application).

Secondary objectives are

  • To geostatiscally evaluate the accuracy of TerraSAR-X elevation models using different polarisations (HH, VV) and different incidence angles (35, 45, 55).
  • To compare the TerraSAR-X DEMs confidence intervals with those of WorldView-1 and Lidar.
  • To determine the confidence intervals that may be achieved using TerraSAR-X DEMs and their associated risks when selecting routes for new OHTLs.

In order to undertake this research, six interferometric pairs in 11-day repeat SpotLight mode in Single Look Slant Range Complex (SSC) format for the study area are required to generate digital elevation models (DEMs). The six interferometric pairs will be a combination of HH and VV polarisations with incidence angles of 35, 45 and 55 degrees. Using this six interferometric pairs different versions of the DEMs will be extracted using different algorithms for phase unwrapping (e.g. branch-cut region growing and minimum cost flow). Then, an initial exploratory analysis of the elevation models will be undertaken by comparing the extracted elevation with accurate ground control points and using statistical descriptors (e.g. RMSE).

Afterwards, the structural analysis of the DEMs will be undertaken in order to quantify and model their spatial variability (e.g. using variograms). Then, stochastic conditional simulation will be used to generate a set of realisations of the error surface obtained in the previous analysis in order to construct local probability distributions of error, estimate the confidence intervals and generate uncertainty maps. The outputs from the geostatistical analysis will be used to evaluate the DEMs fitness for use for selecting routes for new overhead transmission lines (OHTLs).

The expected results are the publication of the results obtained from the geostatistical evaluation and comparison of the elevation models derived from TerraSAR-X (HH and VV) and other data sources (e.g. WorldView-1 and Lidar) and the submission of an accuracy report to DLR. Additionally, the results of the fitness-for-use evaluation may help to establish a commercial earth observation market for TerraSAR-X by demonstrating the potential of the generated elevation models for the route selection process and its associated uncertainties.

Team members

  • Mr. Cutberto U. Paredes Hernández, University of Leicester, UK
  • Dr. Kevin J. Tansey, University of Leicester, UK
  • Dr. Nicholas J. Tate, University of Leicester, UK
  • Prof. Peter F. Fisher, University of Leicester, UK
  • Dr. Wilver E. Salinas Castillo, Universidad Autónoma de Tamaulipas, México

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