COMPARISON BETWEEN ABSOLUTE AND RELATIVE POSITIONAL ACCURACY ASSESSMENT - A CASE STUDY APPLIED TO DIGITAL ELEVATION MODELS

Leandro Luiz Silva De França,João Alberto Batista De Carvalho,Alex De Lima Teodoro Da Penha

doi:10.1590/s1982-21702019000100003

Leandro Luiz Silva De França, João Alberto Batista De Carvalho + Show 1 more

Open Access

https://doi.org/10.1590/s1982-21702019000100003

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Abstract

Abstract This paper presents a comparative study between the absolute and relative methods for altimetric positional accuracy of Digital Elevation Models (DEM). For the theoretical basis of this research, the definitions of accuracy (exactness) and precision, as well the concepts related to absolute and relative positional accuracy were explored. In the case study, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar Topography Mission (SRTM) DEM were used. In the analysis of the absolute accuracy, 6,568 ground control points from GNSS orbital survey were used, collected through relative-static method. In the relative accuracy, it was used as reference DEM with spatial resolution of 5 meters generated by stereophotogrammetrical process for the Mapping Project of Bahia (Brazil). It was concluded that, once the accuracy of the reference DEM is better than the other two evaluated DEM, the results of the classification for the PEC-PCD for the relative evaluation are equal to or better than the absolute evaluation results, with the advantage to being able to verify the pixel population of the evaluated models, which makes it possible to identify outliers, distortions and displacements, including delimiting regions, which is much less likely with a limited set of control points.

Highlights

The International Organization for Standardization (ISO) gives international norms about geographic information, being developed in its 19,100 series (ISO 19.157, 2013)
The Digital Elevation Models (DEM) ASTER and Shuttle Radar Topography Mission (SRTM) evaluated in this work and presented in figure 1 were obtained from the United States Geological Survey (USGS) EarthExplorer website: https://earthexplorer.usgs.gov
The following tables 5 and 6 present the results of the altimetric positional accuracy assessment for absolute and relative methods, respectively. It is shown statistical results of the calculated errors in meters (m) and the PEC-PCD category in which each ASTER and SRTM DEM have been classified for the following scales: 1:25,000 (25K), 1:50,000 (50k), 1:100,000 (100k) and 1:250,000 (250K)

Summary

Introduction

The International Organization for Standardization (ISO) gives international norms about geographic information, being developed in its 19,100 series (ISO 19.157, 2013). The Brazilian standards were built based on these norms through the National Spatial Data Infrastructure (INDE), according to Decree No 6,666, of November 27, 2008 (Brasil, 2008), with one of its objectives being control quality (DSG, 2016), with the aim of providing, in a standardized way, the methods for the evaluation of geographical data. The construction of these standards, or technical specifications, for the cartography is the responsibility of the Brazilian Army, regarding the series of topographic charts, defined in the scales of 1:250,000 and larger, as determined by Decree-Law No 243, of February 28, 1967, which establishes the guidelines and bases of Brazilian cartography. This is the main reason of analyzing and discussing the results of this type measurement, judging their feasibility or not, for the quality control of Digital Elevation Models (DEM)

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