scholarly journals Geomorpho90m - Global high-resolution geomorphometry layers: empirical evaluation and accuracy assessment

2019 ◽  
Author(s):  
Giuseppe Amatulli ◽  
Daniel McInerney ◽  
Tushar Sethi ◽  
Peter Strobl ◽  
Sami Domisch
Keyword(s):  
High Resolution ◽  
Accuracy Assessment ◽  
Empirical Evaluation ◽  
Shuttle Radar Topography Mission ◽  
The United States ◽  
Rate Of Change ◽  
Environmental Models ◽  
Digital Elevation ◽  
The Difference ◽  
Elevation Model

Topographical relief is composed of the vertical and horizontal variations of the Earth's terrain and drives processes in geography, climatology, hydrology, and ecology. Its assessment and characterisation is fundamental for various types of modelling and simulation analyses. In this regard, the Multi-Error-Removed Improved Terrain (MERIT) Digital Elevation Model (DEM) is the best global, high-resolution DEM currently available at a 3 arc-seconds (90 m) resolution. This is an improved product as multiple error components have been corrected from the underlying Shuttle Radar Topography Mission (SRTM3) and ALOS World 3D - 30 m (AW3D30) DEMs. To depict topographical variations worldwide, we developed the Geomorpho90m dataset comprising of different geomorphometry features derived from the MERIT-DEM. The fully standardised geomorphometry variables consist of layers that describe (i) the rate of change using the first and second order derivatives, (ii) the ruggedness, and (iii) the geomorphology landform. To assess how remaining artefacts in the MERIT-DEM could affect the derived topographic variables, we compared our results with the same variables generated using the 3D Elevation Program (3DEP) DEM, which is the highest quality DEM for the United States of America. We compared the two data sources by calculating the first order derivative (i.e., the rate of change through space measured in degrees) of the difference between a MERIT-derived vs. a 3DEP-derived topographic variable. All newly-created topographic variables are readily available at resolutions of 3 and 7.5 arc-seconds under the WGS84 geographic system, and at a spatial resolution of 100 m under the Equi7 projection. The newly-developed Geomorpho90m dataset provides a globally standardised dataset for environmental models and analyses in the field of geography, geology, hydrology, ecology and biogeography.

scholarly journals Geomorpho90m - Global high-resolution geomorphometry layers: empirical evaluation and accuracy assessment

2019 ◽  
Author(s):  
Giuseppe Amatulli ◽  
Daniel McInerney ◽  
Tushar Sethi ◽  
Peter Strobl ◽  
Sami Domisch
Keyword(s):  
High Resolution ◽  
Accuracy Assessment ◽  
Empirical Evaluation ◽  
Shuttle Radar Topography Mission ◽  
The United States ◽  
Rate Of Change ◽  
Environmental Models ◽  
Digital Elevation ◽  
The Difference ◽  
Elevation Model

Topographical relief is composed of the vertical and horizontal variations of the Earth's terrain and drives processes in geography, climatology, hydrology, and ecology. Its assessment and characterisation is fundamental for various types of modelling and simulation analyses. In this regard, the Multi-Error-Removed Improved Terrain (MERIT) Digital Elevation Model (DEM) is the best global, high-resolution DEM currently available at a 3 arc-seconds (90 m) resolution. This is an improved product as multiple error components have been corrected from the underlying Shuttle Radar Topography Mission (SRTM3) and ALOS World 3D - 30 m (AW3D30) DEMs. To depict topographical variations worldwide, we developed the Geomorpho90m dataset comprising of different geomorphometry features derived from the MERIT-DEM. The fully standardised geomorphometry variables consist of layers that describe (i) the rate of change using the first and second order derivatives, (ii) the ruggedness, and (iii) the geomorphology landform. To assess how remaining artefacts in the MERIT-DEM could affect the derived topographic variables, we compared our results with the same variables generated using the 3D Elevation Program (3DEP) DEM, which is the highest quality DEM for the United States of America. We compared the two data sources by calculating the first order derivative (i.e., the rate of change through space measured in degrees) of the difference between a MERIT-derived vs. a 3DEP-derived topographic variable. All newly-created topographic variables are readily available at resolutions of 3 and 7.5 arc-seconds under the WGS84 geographic system, and at a spatial resolution of 100 m under the Equi7 projection. The newly-developed Geomorpho90m dataset provides a globally standardised dataset for environmental models and analyses in the field of geography, geology, hydrology, ecology and biogeography.

scholarly journals Validation of SRTM X Band DEM over Himalayan Mountain

2014 ◽  
Vol XL-4 ◽  
pp. 71-74 ◽  
Author(s):  
R. D. Gupta ◽  
M. K. Singh ◽  
S. Snehmani ◽  
A. Ganju
Keyword(s):  
High Resolution ◽  
Accuracy Assessment ◽  
Mountainous Regions ◽  
Digital Elevation ◽  
X Band ◽  
Global Positioning ◽  
Himalayan Mountain ◽  
Elevation Model ◽  
First Time ◽  
The Himalaya

The present research study assesses the accuracy of the SRTM X band DEM with respect to high accuracy photogrammetric Digital Elevation Model (DEM) for parts of the Himalaya. The high resolution DEM was generated for Manali and nearby areas using digital aerial photogrammetric survey data of 40 cm Ground Sampling Distance (GSD) captured through airborne ADS80 pushbroom camera for the first time in Indian Himalayan context. This high resolution DEM was evaluated with Differential Global Positioning System (DGPS) points for accuracy assessment. The ADS80-DEM gave root mean square error (RMSE) of ~<1m and linear error of 1.60 m at 90 % confidence (LE 90) when compared with the DGPS points. The overall RMSE in vertical accuracy was 73.36 m while LE 90 was 75.20 m with regard to ADS80 DEM. It is observed that the accuracy achieved for part of Himalayan region is far less as compared to the values officially claimed. Thus, SRTM X band DEM should be used with due care in mountainous regions of Himalaya.

scholarly journals Comparison of Vertical Accuracy of Open-Source Global Digital Elevation Models: A Case Study of Adama City, Ethiopia

2021 ◽  
Vol 12 (4) ◽  
pp. 1731-1744
Author(s):  
Hailu Zewde Abili
Keyword(s):  
Open Source ◽  
Thermal Emission ◽  
Accuracy Assessment ◽  
Shuttle Radar Topography Mission ◽  
Surface Model ◽  
Aster Gdem ◽  
Digital Elevation ◽  
Wide Range ◽  
Vertical Accuracy ◽  
Elevation Model

DEM can be generated from a wide range of sources including land surveys, Photogrammetry, and Remote sensing satellites. SRTM 30m DEM by The Shuttle Radar Topography Mission (SRTM), the Global Digital Elevation Model by Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER GDEM) and a global surface model called ALOS Worldview 3D 30 meter (AW3D30) by Advanced Land Observing Satellite (ALOS) are satellite-based global DEMs open-source DEM datasets. This study aims to assess the vertical accuracy of ASTER GDEM2, SRTM 30m, and ALOS (AW3D30) global DEMs over Ethiopia in the study area-Adama by using DGPS points and available accurate reference DEM data. The method used to evaluate the vertical accuracy of those DEMs ranges from simple visual comparison to relative and absolute comparisons providing quantitative assessment (Statistical) that used the elevation differences between DEM datasets and reference datasets. The result of this assessment showed better accuracy of SRTM 30m DEM (having RMSE of ± 4.63 m) and closely followed by ALOS (AW3D30) DEM which scored RMSE of ± 5.25 m respectively. ASTER GDEM 2 showed the least accuracy by scoring RMSE of ± 11.18 m in the study area. The second accuracy assessment was done by the analysis of derived products such as slope and drainage networks. This also resulted in a better quality of DEM derived products for SRTM than ALOS DEM and ASTER GDEM.

scholarly journals Accuracy assessment of TanDEM-X IDEM using airborne LiDAR on the area of Poland

2017 ◽  
Vol 66 (1) ◽  
pp. 137-148 ◽  
Author(s):  
Małgorzata Woroszkiewicz ◽  
Ireneusz Ewiak ◽  
Paulina Lulkowska
Keyword(s):  
Digital Elevation Model ◽  
Laser Scanning ◽  
Accuracy Assessment ◽  
Shuttle Radar Topography Mission ◽  
Reference Points ◽  
Airborne Lidar ◽  
Surface Model ◽  
Digital Elevation ◽  
Elevation Model ◽  
German Aerospace

Abstract The TerraSAR-X add-on for Digital Elevation Measurement (TanDEM-X) mission launched in 2010 is another programme – after the Shuttle Radar Topography Mission (SRTM) in 2000 – that uses space-borne radar interferometry to build a global digital surface model. This article presents the accuracy assessment of the TanDEM-X intermediate Digital Elevation Model (IDEM) provided by the German Aerospace Center (DLR) under the project “Accuracy assessment of a Digital Elevation Model based on TanDEM-X data” for the southwestern territory of Poland. The study area included: open terrain, urban terrain and forested terrain. Based on a set of 17,498 reference points acquired by airborne laser scanning, the mean errors of average heights and standard deviations were calculated for areas with a terrain slope below 2 degrees, between 2 and 6 degrees and above 6 degrees. The absolute accuracy of the IDEM data for the analysed area, expressed as a root mean square error (Total RMSE), was 0.77 m.

scholarly journals Assessing the influence of DEM source on derived streamline and catchment boundary accuracy

Water SA ◽  
2019 ◽  
Vol 45 (4 October) ◽  
Author(s):  
Zama Eric Mashimbye ◽  
Willem Petrus De Clercq ◽  
Adriaan Van Niekerk
Keyword(s):  
High Resolution ◽  
Figure Of Merit ◽  
Euclidean Distance ◽  
Thermal Emission ◽  
Absolute Error ◽  
Shuttle Radar Topography Mission ◽  
The Novel ◽  
Digital Elevation ◽  
Elevation Model

Accurate DEM-derived streamlines and catchment boundaries are essential for hydrological modelling. Due to the popularity of hydrological parameters derived mainly from free DEMs, it is essential to investigate the accuracy of these parameters. This study compared the spatial accuracy of streamlines and catchment boundaries derived from available digital elevation models in South Africa. Two versions of Stellenbosch University DEMs (SUDEM5 and DEMSA2), the second version of the 30 m advanced spaceborne thermal emission and reflection radiometer global digital elevation model (ASTER GDEM2), the 30 and 90 m shuttle radar topography mission (SRTM30 and SRTM90 DEM), and the 90 m Water Research Commission DEM (WRC DEM) were considered. As a reference, a 1 m GEOEYE DEM was generated from GeoEye stereo images. Catchment boundaries and streamlines were extracted from the DEMs using the Arc Hydro module. A reference catchment boundary was generated from the GEOEYE DEM and verified during field visits. Reference streamlines were digitised at a scale of 1:10 000 from the 1 m orthorectified GeoEye images. Visual inspection, as well as quantitative measures such as correctness index, mean absolute error, root mean squares error and figure of merit index were used to validate the results. The study affirmed that high resolution (<30 m) DEMs produce more accurate parameters and that DEM source and resampling techniques also play a role. However, if high resolution DEMs are not available, the 30 m SRTM DEM is recommended as its vertical accuracy was relatively high and the quality of the streamlines and catchment boundary was good. In addition, it was found that the novel Euclidean distance-based MAE and RMSE proposed in this study to compare reference and DEM-extracted raster datasets of different resolutions is a more reliable indicator of geometrical accuracy than the correctness and figure of merit indices.

scholarly journals Study of Digital Elevation Model (DEM) Extraction using Stereo Radargrammetry TerraSAR-X in Madiun Area – Elevation Accuracy Improvement

2019 ◽  
Vol 94 ◽  
pp. 04003 ◽  
Author(s):  
Inggit L. Sari ◽  
Rachmat Maulana ◽  
Haris S. Dyatmika ◽  
Agus Suprijanto ◽  
Rahmat Arief ◽  
...  
Keyword(s):  
High Resolution ◽  
Digital Elevation Model ◽  
Field Observation ◽  
Incidence Angle ◽  
Accuracy Assessment ◽  
Surface Elevation ◽  
Accuracy Improvement ◽  
Digital Elevation ◽  
High Resolution Images ◽  
Elevation Model

High resolution images data from Terrasar-X are used to extract digital elevation model (DEM) using stereo radargrammetry in the attempt to achieve better resolution of terrain surface in Indonesia. As sample in this study, stereo pairs images from TerraSAR-X StripMap mode (~3m resolution) on Madiun city is used with difference of incidence angle around ~18.88 degree to extract the elevation of the area. Furthermore, field observation on the selected area will be used on elevation accuracy assessment. The digital surface elevation (DSM) generated by stereo radargrammetry in this study shows us high resolution with spatial pixel spacing 5.57 meter and elevation accuracy around ~4 meter.

scholarly journals Identification and mapping of recent rainfall-induced landslides using elevation data collected by airborne Lidar

2007 ◽  
Vol 7 (6) ◽  
pp. 637-650 ◽  
Author(s):  
F. Ardizzone ◽  
M. Cardinali ◽  
M. Galli ◽  
F. Guzzetti ◽  
P. Reichenbach
Keyword(s):  
High Resolution ◽  
Linear Interpolation ◽  
Airborne Lidar ◽  
Landslide Area ◽  
Digital Elevation ◽  
Swath Mapping ◽  
Elevation Data ◽  
Inventory Map ◽  
The Difference ◽  
Elevation Model

Abstract. A high resolution Digital Elevation Model with a ground resolution of 2 m×2 m (DEM2) was obtained for the Collazzone area, central Umbria, through weighted linear interpolation of elevation points acquired by Airborne Lidar Swath Mapping. Acquisition of the elevation data was performed on 3 May 2004, following a rainfall period that resulted in numerous landslides. A reconnaissance field survey conducted immediately after the rainfall period allowed mapping 70 landslides in the study area, for a total landslide area of 2.7×105 m2. Topographic derivative maps obtained from the DEM2 were used to update the reconnaissance landslide inventory map in 22 selected sub-areas. The revised inventory map shows 27% more landslides and 39% less total landslide area, corresponding to a smaller average landslide size. Discrepancies between the reconnaissance and the revised inventory maps were attributed to mapping errors and imprecision chiefly in the reconnaissance field inventory. Landslides identified exploiting the Lidar elevation data matched the local topography more accurately than the same landslides mapped using the existing topographic maps. Reasons for the difference include an incomplete or inaccurate view of the landslides in the field, an unfaithful representation of topography in the based maps, and the limited time available to map the landslides in the field. The high resolution DEM2 was compared to a coarser resolution (10 m×10 m) DEM10 to establish how well the two DEMs captured the topographic signature of landslides. Results indicate that the improved topographic information provided by DEM2 was significant in identifying recent rainfall-induced landslides, and was less significant in improving the representation of stable slopes.

Line of Sight Analysis 

2021 ◽  
Author(s):  
Emily Law ◽  
Natalie Gallegos ◽  
Shan Malhotra
Keyword(s):  
High Resolution ◽  
Solar System ◽  
High Gain ◽  
Line Of Sight ◽  
Time Intervals ◽  
Ground Station ◽  
Points Of Interest ◽  
Digital Elevation ◽  
Initial Release ◽  
Elevation Model

&lt;p&gt;The Line of Sight (LoS) is one of the latest tools to join the analytics suite of tools for the Solar System Treks (https://trek.nasa.gov) portals.&amp;#160; The LoS tool provides a way to compute visibility between the entities in our solar system. More concretely, this utility searches for windows of communication or a &amp;#8220;line of sight&amp;#8221; between any two entities. Entities include orbiters, rovers, planetary bodies, ground stations, and other topographical locations. In addition to establishing communications between the two entities, the tool also takes into account local terrains of the entities in question.&lt;/p&gt; &lt;p&gt;The software seeks to answer questions about establishing communications between a rover and an orbiter, or an orbiter to a ground station. In mission planning, LoS can be used to determine possible traverses for a rover that must maintain communications with a lander, or find time intervals of communication to an orbiter when a rover or lander are near an obstructing surface feature such as a crater rim or mound. Computations can be even more granular and lines of sight can be computed between mission instruments, thus allowing to ask questions such as &amp;#8220;Is the High Gain Antenna on a rover visible from an orbiter?&amp;#8221;&lt;/p&gt; &lt;p&gt;The initial release of the software focuses on the lunar surface and the LRO spacecraft. Users can ask whether a topographical location on the moon is visible from the orbiter or a discrete set of ground stations on Earth. The tool uses NAIF SPICE and various mission kernels for computing planetary geometries. LoS also uses high resolution Digital Elevation Model (DEM) to model the terrain surrounding the points of interest. In-house software is used to convert high resolution DEMs into a format compatible with the tool. Users can provide their own DEMs to model the terrain on different topographical locations to use for their own computations.&lt;/p&gt;

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