Accuracy, reliability, and depuration of SPOT-HRV and Terra ASTER Digital Elevation Models (original) (raw)
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ACCURACY ASSESSMENT OF DIGITAL ELEVATION MODELS OBTAINED FROM DIFFERENT DATA AND METHODS
ACCURACY ASSESSMENT OF DIGITAL ELEVATION MODELS OBTAINED FROM DIFFERENT DATA AND METHODS, 2017
Digital elevation model (DEM) is primarily a way of visualising 2D maps, photographs and images in 3D. Common uses of DEMs are creation of relief maps, rendering of 3D visualizations, rectification of satellites images and aerial photographs, creation of different physical models, etc. DEMs can be produced by different methods. In this study, DEMs are produced by 1:25000 digital topographic maps, Light Detection and Ranging (LIDAR) data, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Shuttle Radar Topographic Mission (SRTM) data, and the accuracy of these models are analysed.
Results of Automated Digital Elevation Model Generation from SPOT Satellite Data
2010
Some recent results of a Digital Elevation Model (DEM) generation system for Landsat and SPOT stereo imagery are presented. A wide range of test imagery, including imagery affected by radiometric change due to multitemporal and atmospheric effects, as well as areas with a variety of topography were used to study the system's performance. Several reference DEMs of high accuracy and density were used to compare the derived DEMs at approximately 50,000 check points. Height accuracies better than 7 metres RMS were produced for a variety of the tested areas. Considerations given to the automatic processing of this data are presented as well as the use of spacecraft modelling which results in high DEM accuracy with very few ground control points.
Evaluation of the Accuracy of Digital Elevation Model Produced from Different Open Source Data
Journal of Engineering, 2019
This study aims to estimate the accuracy of digital elevation models (DEM) which are created with exploitation of open source Google Earth data and comparing with the widely available DEM datasets, Shuttle Radar Topography Mission (SRTM), version 3, and Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM), version 2. The GPS technique is used in this study to produce digital elevation raster with a high level of accuracy, as reference raster, compared to the DEM datasets. Baghdad University, Al Jadriya campus, is selected as a study area. Besides, 151 reference points were created within the study area to evaluate the results based on the values of RMS. Furthermore, the Geographic Information System (GIS) was utilized to analyze, imagine and interpolate data in this study. The result of the statistical analysis revealed that RMSE of DEM related to the differences between the reference points and Google Earth, SRTM DEM and ASTER GDEM are 6.9, 5.5 and 4.8, respectively. What is more, a finding of this study shows convergence the level of accuracy for all open sources used in this study.
ISPRS Journal of Photogrammetry and Remote Sensing, 2014
High-resolution digital elevation models (DEMs) generated by airborne remote sensing are frequently used to analyze landform structures (monotemporal) and geomorphological processes (multitemporal) in remote areas or areas of extreme terrain. In order to assess and quantify such structures and processes it is necessary to know the absolute accuracy of the available DEMs. This study assesses the absolute vertical accuracy of DEMs generated by the High Resolution Stereo Camera-Airborne (HRSC-A), the Leica Airborne Digital Sensors 40/80 (ADS40 and ADS80) and the analogue camera system RC30. The study area is located in the Turtmann valley, Valais, Switzerland, a glacially and periglacially formed hanging valley stretching from 2400 m to 3300 m a.s.l. The photogrammetrically derived DEMs are evaluated against geodetic field measurements and an airborne laser scan (ALS). Traditional and robust global and local accuracy measurements are used to describe the vertical quality of the DEMs, which show a non Gaussian distribution of errors. The results show that all four sensor systems produce DEMs with similar accuracy despite their different setups and generations. The ADS40 and ADS80 (both with a ground sampling distance of 0.50 m) generate the most accurate DEMs in complex high mountain areas with a RMSE of 0.8 m and NMAD of 0.6 m They also show the highest accuracy relating to flying height (0.14‰). The pushbroom scanning system HRSC-A produces a RMSE of 1.03 m and a NMAD of 0.83 m (0.21‰ accuracy of the flying height and 10 times the ground sampling distance). The analogue camera system RC30 produces DEMs with a vertical accuracy of 1.30 m RMSE and 0.83 m NMAD (0.17‰ accuracy of the flying height and two times the ground sampling distance). It is also shown that the performance of the DEMs strongly depends on the inclination of the terrain. The RMSE of areas up to an inclination <40°is better than 1 m. In more inclined areas the error and outlier occurrence increase for all DEMs. This study shows the level of detail to which airborne stereoscopically derived DEMs can reliably be used in high mountain environments. All four sensor systems perform similarly in flat terrain. Ó
An Assessment of Digital Elevation Models (DEMs) From Different Spatial Data Sources
Digital Elevation Model (DEM) represents a very important geospatial data type in the analysis and modelling of different hydrological and ecological phenomenon which are required in preserving our immediate environment. DEMs are typically used to represent terrain relief. DEMs are particularly relevant for many applications such as lake and water volumes estimation, soil erosion volumes calculations, flood estimate, quantification of earth materials to be moved for channels, roads, dams, embankment etc.
Performance evaluation of global and absolute DEMs generated from ASTER stereo imagery
2011
The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) digital stereo image could be used to generate Digital Elevation Model (DEM), which represents the terrain elevation in discrete three dimensional (3D) forms. In this research, the performance of the absolute and Global DEMs generated from ASTER stereo image is evaluated for the area of Universiti Teknologi Malaysia (UTM). In doing so, 25 Ground Control Points (GCPs) collected by Global Positioning System (GPS) instrument are used to extract an absolute ASTER DEM. Furthermore, the ASTER Global DEM (GDEM) is acquired for the study area. The accuracy of the DEMs is assessed by comparing them with 20 high accuracy points which were collected using GPS technology. Some statistical parameters such as the Mean Error (ME), Standard Deviation (SD) and Root Mean Square Error (RMSE) are determined for this purpose. The achieved results indicated that the estimated vertical accuracy of the ASTER GDEM is less than 5 m at 80% confidence for the study area while the vertical accuracy of less than 15 m is obtained for the ASTER absolute DEM, which is less than the pixel size of ASTER image. Finally, according to the achieved results, 15 m resolution of ASTER image and the selected number of check points, it can be concluded that the accuracy of DEMs is acceptable for the study area, and could be used for various geoinformation applications.
DEM Accuracy of High Resolution Satellite Images
Lecture Notes in Computer Science
The aim of this research is to study the accuracy of Digital Elevation Models (DEMs) generated from two different satellite data namely OrbView-3 and IKONOS stereo images. 21 GCPs (Ground Control Points), 182 CPs (Check Points) and selected transects representing different land covers and topography were used for the accuracy analysis. Two DEMs were generated from OrbView-3 and one DEM from IKONOS stereo data. The accuracy of the used model for DEM generation was quantified using the RMSE (Root Mean Square Error) values of GCPs derived from Global Positioning System survey and error analysis over research area was performed using 182 CPs derived from traditional field survey. Several transects were formed over different parts of the study area and height values along these transects obtained from different DEMs were compared to determine and examine the accuracy. The results are analyzed with the empirical accuracy criterion for heights on analog maps.
ACCURACY OF DEM GENERATION FROM TERRA-ASTER STEREO DATA
In this work we studied the accuracy of DEMs generated from ASTER stereoscopic images by automated stereo-matching techniques with two different softwares (OrthoBase PRO and OrthoEngine). We compare several DEMs generated for a test area of 23 km x 28 km situated in the province of Granada (south Spain). This is an area was selected because its variable and complex topography with elevations ranging from 300m up to 2800 m.
Accuracy Enhancement of ASTER Global Digital Elevation Models Using ICESat Data
Global Digital Elevation Models (GDEM) are considered very attractive for current research and application areas due to their free and wide range accessibility. The ASTER Global Digital Elevation Model exhibits the highest spatial resolution data of all global DEMs and it is generated for almost the whole globe. Unfortunately, ASTERGDEM data include many artifacts and height errors that decrease the quality and elevation accuracy significantly. This study provides a method for quality improvement of the ASTER GDEM data by correcting systematic height errors using ICESat laser altimetry data and removing artifacts and anomalies based on a segment-based outlier detection and elimination algorithm. Additionally, elevation errors within water bodies are corrected using a water mask produced from a high-resolution shoreline data set. Results indicate that the accuracy of the corrected ASTER GDEM is significantly improved and most artifacts are appropriately eliminated. Nevertheless, artifacts containing lower height values with respect to the neighboring ground pixels are not entirely eliminated due to confusion with some real non-terrain 3D objects. The proposed method is particularly useful for areas where other high quality DEMs such as SRTM are not available.
This paper describes the methodology of a DEM generation from stereo aerial images and the results of experiments in terms of accuracy of generated DEM. In this study, Images, which have 1/10000 and 1/16000 scale, and a test area established about 1 km 2 in Selcuk University Campus Area were used. Aerial photographs were scanned by ZEISS SCAI Photogrammetric Scanner (pixel size is 21µ). Aerial images, which have 1/10000 scale, were restitutied by Zeiss Planicomp P3 Analytical Instrument. The DEM, which belong to test area, were produced by progressive, selective and composite sampling methods. We have developed a new software on PC's that can automatically generate DEM from stereo aerial images for restitution of images 1/16000 scale. In this software, pixel and image coordinates of points in left and right image are calculated by using colinearity equations. Left and right windows are matched and this process is repeated in various ±∆Z range. Elevation values obtained from the best-fixed matching are automatically selected as optimum elevation value. Elevation values of points in the test area are calculated by bilinear interpolation method which uses coordinates of above points (X,Y,Z). Moreover, Elevations of points in test area are manually produced from PHOTOMOD software. RMS obtained from both analytical and digital methods are compared with similar study in the relevant literature.