European Digital Elevation Model Validation against Extensive Global Navigation Satellite Systems Data and Comparison with SRTM DEM and ASTER GDEM in Central Macedonia (Greece)

Antonios Mouratidis,Dimitrios Ampatzidis

doi:10.3390/ijgi8030108

Abstract

Digital elevation models (DEMs) are a widely used form of topographic information, with some of the most popular being the Shuttle Radar Topography Mission (SRTM) DEM and the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM). These two sources of topographical information are the main constituents of the European Union Digital Elevation Model (EU-DEM), which is a relatively new dataset of the EU’s Copernicus Land Monitoring Service. In this context, the purpose of this study was to validate EU-DEM for its vertical accuracy and to compare it with SRTM DEM and ASTER GDEM data. This was achieved in a Geographic Information System (GIS) environment, using extensive—in the order of tens of thousands of points—geodetic Global Navigation Satellite System (GNSS) measurements and appropriate pre-processing steps. The absolute elevation errors results had a Root Mean Square Error (RMSE) of 2.7 m at a 90% confidence level and characterize the performance of EU-DEM from local to regional scale, generally confirming that it is an enhanced source of elevation information when compared with its predecessors.

Highlights

Digital elevation models (DEMs) are the most popular form of topographic data
Considering European Union Digital Elevation Model (EU-DEM) is practically a mathematical product mainly stemming from ASTER GDEM and Shuttle Radar Topography Mission (SRTM) DEM data, prior to assessing the accuracy of the individual DEMs, we acquired an overview of the differences between the three datasets
Histograms (Figures 4 and 5) of the results show that the elevation values of EU-DEM are closer to the “real” values measured by Global Navigation Satellite System (GNSS)

Summary

Introduction

Digital elevation models (DEMs) are the most popular form of topographic data. The positive impact of (almost) global and publicly available DEMs from space-based measurements, such as the Shuttle Radar Topography Mission (SRTM) DEM data [1] and the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM) [2,3,4], has been verified by the plethora of their applications. SRTM DEM has been described as the most dramatic advance in cartography since Mercator [5], whereas current products, like ALOS Global Digital Surface Model “ALOS World 3D–30 m (AW3D30)” [6] or WorldDEMTM [7], and near-future mission concepts such as the Lidar Surface Topography (LIST) [8] emphasize the quest for increasingly accurate descriptions of the global topography and underline the topography’s time dependence, turning its measurement into a continuous task [5] In this context, the European Union Digital Elevation Model (EU-DEM) is a new hybrid product principally based on SRTM DEM and ASTER GDEM data, and on publically available Russian topographic maps for regions north of 60◦ N. In April 2016, an updated version (v1.1) of EU-DEM was released as an upgrade that enhances the correction of geo-positioning issues, reducing the number of artefacts, improving the vertical accuracy of EU-DEM, and ensuring consistency with other relevant public EU geospatial data [11]

Objectives

Methods

Results

Discussion

Conclusion