Evaluation of Copernicus DEM and Comparison to the DEM Used for Landsat Collection-2 Processing
Having highly accurate and reliable Digital Elevation Models (DEMs) of the Earth’s surface is critical to orthorectify Landsat imagery. Without such accuracy, pixel locations reported in the data are difficult to assure as accurate, especially in more mountainous landscapes, where the orthorectifica...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-05-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/15/10/2509 |
| _version_ | 1827740242237456384 |
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| author | Shannon Franks Rajagopalan Rengarajan |
| author_facet | Shannon Franks Rajagopalan Rengarajan |
| author_sort | Shannon Franks |
| collection | DOAJ |
| description | Having highly accurate and reliable Digital Elevation Models (DEMs) of the Earth’s surface is critical to orthorectify Landsat imagery. Without such accuracy, pixel locations reported in the data are difficult to assure as accurate, especially in more mountainous landscapes, where the orthorectification process is the most challenging. To this end, the Landsat Calibration and Validation Team (Cal/Val) compared the Copernicus DEM (CopDEM) to the DEM that is currently used in Collection-2 processing (called “Collection-2 DEM”). NGS ground-surveyed and lidar-based ICESat-2 points were used, and the CopDEM shows improvement to be less than 1 m globally, except in Asia where the accuracy and resolution of the DEM were greater for the CopDEM compared to the Collection-2 DEM. Along with slightly improved accuracy, the CopDEM showed more consistent results globally due to its virtually seamless source and consistent creation methods throughout the dataset. While CopDEM is virtually seamless, having greater than 99% of their data coming from a single source (Tandem-X), there are significantly more voids in the higher elevations which were mostly filled with SRTM derivatives. The accuracy of the CopDEM fill imagery was also compared to the Collection-2 DEM and the results were very similar, showing that the choice of fill imagery used by CopDEM was appropriate. A qualitative assessment using terrain-corrected products processed with different DEMs and viewing them as anaglyphs to evaluate the DEMs proved useful for assessing orbital path co-registration. While the superiority of the CopDEM was not shown to be definitive by the qualitative method for many of the regions assessed, the CopDEM showed a clear advantage in Northern Russia, where the Collection-2 DEM uses some of the oldest and least accurate datasets in the compilation of the Collection-2 DEM. This paper presents results from the comparison study, along with the justification for proceeding with using the Copernicus DEM in future Landsat processing. As of this writing, the Copernicus DEM is planned to be used in Collection-3 processing, which is anticipated to be released no earlier than 2025. |
| first_indexed | 2024-03-11T03:22:12Z |
| format | Article |
| id | doaj.art-39ba96bb1fd44443ac9ffac06e69d03c |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-11T03:22:12Z |
| publishDate | 2023-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-39ba96bb1fd44443ac9ffac06e69d03c2023-11-18T03:06:07ZengMDPI AGRemote Sensing2072-42922023-05-011510250910.3390/rs15102509Evaluation of Copernicus DEM and Comparison to the DEM Used for Landsat Collection-2 ProcessingShannon Franks0Rajagopalan Rengarajan1KBR, Contractor to the U.S. Geological Survey, Earth Resources Observation and Science Center, Sioux Falls, SD 57030, USAKBR, Contractor to the U.S. Geological Survey, Earth Resources Observation and Science Center, Sioux Falls, SD 57030, USAHaving highly accurate and reliable Digital Elevation Models (DEMs) of the Earth’s surface is critical to orthorectify Landsat imagery. Without such accuracy, pixel locations reported in the data are difficult to assure as accurate, especially in more mountainous landscapes, where the orthorectification process is the most challenging. To this end, the Landsat Calibration and Validation Team (Cal/Val) compared the Copernicus DEM (CopDEM) to the DEM that is currently used in Collection-2 processing (called “Collection-2 DEM”). NGS ground-surveyed and lidar-based ICESat-2 points were used, and the CopDEM shows improvement to be less than 1 m globally, except in Asia where the accuracy and resolution of the DEM were greater for the CopDEM compared to the Collection-2 DEM. Along with slightly improved accuracy, the CopDEM showed more consistent results globally due to its virtually seamless source and consistent creation methods throughout the dataset. While CopDEM is virtually seamless, having greater than 99% of their data coming from a single source (Tandem-X), there are significantly more voids in the higher elevations which were mostly filled with SRTM derivatives. The accuracy of the CopDEM fill imagery was also compared to the Collection-2 DEM and the results were very similar, showing that the choice of fill imagery used by CopDEM was appropriate. A qualitative assessment using terrain-corrected products processed with different DEMs and viewing them as anaglyphs to evaluate the DEMs proved useful for assessing orbital path co-registration. While the superiority of the CopDEM was not shown to be definitive by the qualitative method for many of the regions assessed, the CopDEM showed a clear advantage in Northern Russia, where the Collection-2 DEM uses some of the oldest and least accurate datasets in the compilation of the Collection-2 DEM. This paper presents results from the comparison study, along with the justification for proceeding with using the Copernicus DEM in future Landsat processing. As of this writing, the Copernicus DEM is planned to be used in Collection-3 processing, which is anticipated to be released no earlier than 2025.https://www.mdpi.com/2072-4292/15/10/2509orthorectificationDEMLandsatCopernicusSRTMArcticDEM |
| spellingShingle | Shannon Franks Rajagopalan Rengarajan Evaluation of Copernicus DEM and Comparison to the DEM Used for Landsat Collection-2 Processing Remote Sensing orthorectification DEM Landsat Copernicus SRTM ArcticDEM |
| title | Evaluation of Copernicus DEM and Comparison to the DEM Used for Landsat Collection-2 Processing |
| title_full | Evaluation of Copernicus DEM and Comparison to the DEM Used for Landsat Collection-2 Processing |
| title_fullStr | Evaluation of Copernicus DEM and Comparison to the DEM Used for Landsat Collection-2 Processing |
| title_full_unstemmed | Evaluation of Copernicus DEM and Comparison to the DEM Used for Landsat Collection-2 Processing |
| title_short | Evaluation of Copernicus DEM and Comparison to the DEM Used for Landsat Collection-2 Processing |
| title_sort | evaluation of copernicus dem and comparison to the dem used for landsat collection 2 processing |
| topic | orthorectification DEM Landsat Copernicus SRTM ArcticDEM |
| url | https://www.mdpi.com/2072-4292/15/10/2509 |
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