The New Landsat Collection-2 Digital Elevation Model

Shannon Franks,James Storey,Rajagopalan Rengarajan

doi:10.3390/rs12233909

Shannon Franks, James Storey + Show 1 more

Open Access

https://doi.org/10.3390/rs12233909

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Abstract

The Landsat Collection-2 distribution introduces a new global Digital Elevation Model (DEM) for scene orthorectification. The new global DEM is a composite of the latest and most accurate freely available DEM sources and will include reprocessed Shuttle Radar Topographic Mission (SRTM) data (called NASADEM), high-resolution stereo optical data (ArcticDEM), a new National Elevation Dataset (NED) and various publicly available national datasets including the Canadian Digital Elevation Model (CDEM) and DEMs for Sweden, Norway and Finland (SNF). The new DEM will be available world-wide with few exceptions. It is anticipated that the transition from the Collection-1 DEM at 3 arcsecond to the new DEM will be seamless because processing methods to maintain a seamless transition were employed, void filling techniques were used, where persistent gaps were found, and the pixel spacing is the same between the two collections. Improvements to the vertical accuracy were realized by differencing accuracies of other elevation datasets to the new DEM. The greatest improvement occurred where ArcticDEM data were used, where an improvement of 35 m was measured. By using theses improved vertical values in a line of sight algorithm, horizontal improvements were noted in some of the most mountainous regions over multiple 30-m Landsat pixels. This new DEM will be used to process all of the scenes from Landsat 1-8 in Collection-2 processing and will be made available to the public by the end of 2020.

Highlights

The U.S Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center processes and delivers Landsat terrain-corrected products to the public through the implementation of Collections
The improved global elevation dataset from this study, called the Landsat Collection-2 Digital Elevation Models (DEM) or Collection-2 DEM, is expected to be released by the end 2020 and will be used to process the entire Landsat archive in Collection-2 processing
The primary reference data used in this study to estimate error were from the Airbus WorldDEM elevation model served by the Environmental Systems Research Institute, Inc. (Esri) through their Geographic Information System (GIS) platforms

Summary

Introduction

The U.S Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center processes and delivers Landsat terrain-corrected products to the public through the implementation of Collections. In order to improve the geometric accuracy of the Landsat orthorectified products in Collection-2 processing, the CalVal Team at the USGS EROS Center initiated a study to determine if better DEM datasets were available to replace the existing Collection-1 DEM. Accuracy assessment studies on these global DEMs have shown that the overall vertical accuracies are significantly better than the SRTM dataset, but each of these datasets presents additional challenges in terms of global coverage, voids and artifacts such as spikes and pits [3,4,5,6,7] Using elevation sources such as ICESat and GDEM3, the NASADEM improved the vertical accuracy and removed spikes observed in the earlier version of the SRTM data [2].

ArcticDEM

Esri-Served Airbus WorldDEM

Methodology

Conclusions