Performance evaluation of global and absolute DEMs generated from ASTER stereo imagery (original) (raw)
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Accuracy Assessment of Digital Elevation Model (DEM) Data Obtained from ASTER Satellite in Flat Land
IOP Conference Series: Materials Science and Engineering
It is important to investigate the accuracy of Digital Elevation Models (DEMs) because of their crucial impact on all engineering and scientific disciplines. Photogrammetry, traditional surveying, remote sensing systems and satellite whole DEMs output methods. In this paper include the DEM data produced by the ASTER satellite (Band near-infrared wavelength region from 0.78 to 0.86 μm), where tested and evaluation DEM data for an area of 100 square kilometers in Al-Shtra city. The technique used to evaluate was twofold: first method was to use statistical methods; second method is to take advantage of applied linear transformation equation to detect the gap between Z-DEM and Z-Global Navigation Satellite System (GNSS) (which represents reality (. The result of a root means square error (RMSE) is 5.087m, where it was calculated based on the observed data in the field using GNSS. And standard deviation error (SDT err) was 5.088 m, while after applied linear transformation equation the RMSE reduction to about 80%, which indicates a large bias between the Z-DEM and Z-GPS.
Digital elevation model (DEM) is a digital representation of ground surface topography and have been used in various applications. The introduction of global coverage DEM available for free or at reasonable cost was a new phenomenon in mapping. The issue is how accurate are these datasets and can it be used for topographic mapping. This paper aims to evaluate the height accuracy of DEMs generated from different sources. Results presented in this paper is part of a study to evaluate the suitable use of different DEMs and high resolution imagery for topographic map updating. For this paper, Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM), Intermap Airborne Interferometric Synthetic Aperture Radar Digital Terrain Model (IFSAR DTM), IFSAR Digital Surface Model (IFSAR DSM), digital topographic map (with a 5m contour interval) and Light Detection and Ranging (LiDAR) datasets are used to generate the contours, height points and height profiles. LiDAR dataset is used as reference DEM to evaluate the accuracy of NEXTMap IFSAR DTM and Digital Terrain Model (DTM) generated from digital topographic maps acquired from the Department of Survey and Mapping Malaysia. The vertical accuracy of ASTER GDEM is obtained by comparing wih the heights of IFSAR DSM. The Root Mean Squares Error (RMSE) of the height points generated from IFSAR DTM and digital topographic map of the non-vegetated areas within the study area are 1.458 m and 2.960 m respectively. For the vegetated area, the RMSE of IFSAR DTM and digital topographic map are 4.736 m and 9.848 m respectively. The accuracy of ASTER GDEM in the vegetated and non-vegetated areas are 8.442 m and 18.900 m respectively. Visual comparison between the contours generated from IFSAR DTM and LiDAR has shown promising result. ASTER GDEM can be used to capture the general characteristic of the terrain. Future work will include the evaluation of factors that contribute to the accuracy of DEMs generated from different sources.
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.
Accuracy Assessment of Aster Global Dem Over Turkey
2010
The aim of this study is to analyze the accuracy of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) over Istanbul metropolitan city. Accuracy assessment was conducted by comparing ASTER GDEM with a reference DEM derived from 1/5.000-scaled topographic maps. The selected area has wide range of elevations since it covers coastal and mountainous areas. Different land cover types like urban, sea, lakes, agricultural land, forest, grasslands, bare lands are available within the study area. The accuracy assessment of GDEM was performed by visual interpretation and statistical analysis. Throughout the statistical analysis, several transects representing different types of land cover and topography were selected and minimum, maximum and mean errors and Root Mean Square Error values of each transect were calculated, respectively. The quality of ASTER GDEM was analyzed for Istanbul region and it was found that ASTER GDEM could repre...
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.
International Journal of Computing, Communication and Instrumentation Engineering
A Digital Elevation Model (DEM) is a digital representation of ground surface topography. DEMs are used for various applications including flood modeling. The objective of this paper is to evaluate the vertical accuracy of the DEMs acquired from different sources. The study area covered several districts in Kedah, Malaysia. To determine the accuracies of DEMs acquired from NEXTMap Interferometric Synthetic Aperture Radar (IFSAR), ASTER Global Digital Elevation Model (GDEM) and SRTM Void Fill, height points are compared with the Global Positioning System (GPS) height observations. A total of 100 height points extracted from ASTER GDEM and SRTM is also compared with IFSAR Digital Surface Model (DSM). Four (4) different elevation profiles are generated and the heights are compared. The results obtained have shown that the Root Mean Squares Errors (RMSEs) of IFSAR DTM, IFSAR DSM, ASTER GDEM and SRTM over a relatively flat area are ±0.497 m, ±1.529 m, ±5.848 m and ±4.268 m respectively. Over an undulating area, the accuracies of IFSAR DTM, IFSAR DSM, ASTER GDEM and SRTM are ±0.841 m, ±2.092 m, ±3.278 m and ± 5.300 m respectively. Although there are variations between heights generated from these DEMs in some areas along cross-section, the pattern of height profiles is still quite similar. Future work will concentrate on the techniques of converting DEM acquired from ASTER GDEM and SRTM into DSM and the effects of using different DEMs on the accuracy flood inundation mapping.
Google Earth’s derived digital elevation model: A comparative assessment with Aster and SRTM data
This paper presents a statistical analysis showing additional evidence that Digital Elevation Model (DEM) derived from Google Earth is commendable and has a good correlation with ASTER (Advanced Space-borne Thermal Emission and Reflection Radiometer) and SRTM (Shuttle Radar Topography Mission) elevation data. The accuracy of DEM elevation points from Google Earth was compared against that of DEMs from ASTER and SRTM for flat, hilly and mountainous sections of a pre-selected rural watershed. For each section, a total of 5,000 DEM elevation points were extracted as samples from each type of DEM data. The DEM data from Google Earth and SRTM for flat and hilly sections are strongly correlated with the R 2 of 0.791 and 0.891 respectively. Even stronger correlation is shown for the mountainous section where the R 2 values between Google Earth's DEM and ASTER's and between Google Earth's DEM and SRTM's DEMs are respectively 0.917 and 0.865. Further accuracy testing was carried out by utilising the DEM dataset to delineate Muar River's watershed boundary using ArcSWAT2009, a hydrological modelling software. The result shows that the percentage differences of the watershed size delineated from Google Earth's DEM compared to those derived from Department of Irrigation and Drainage's data (using 20m-contour topographic map), ASTER and SRTM data are 9.6%, 10.6%, and 7.6% respectively. It is therefore justified to conclude that the DEM derived from Google Earth is relatively as acceptable as DEMs from other sources.
Accuracy Analysis of Dems Derived from Aster Imagery
ASTER acquires along track stereoscopic imagery, with a spatial resolution of 15 meters. Automatic generation of Digital Elevation Models (DEMs) from these images is a well established process, implemented in many commercial software packages. It can provide relief information for areas with poor coverage of topographic mapping. This paper presents a study of the accuracy achieved in DEMs extracted from ASTER, for an area in Portugal, using the PCI OrthoEngine software. Images were orientated with ground control points (GCP) obtained from topographic maps. Experiments were carried out in reducing the number of GCPs. A number of 5 or 6 GCPs was always required to orient the images, in order to keep the accuracy achieved with larger numbers of points. It was possible to conclude that more use could have been done of the approximate orientation provided in the image header. A grid of points derived from the sensor position and attitude, estimated by onboard equipment, is given in the i...
The along-track stereo images of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor with 15 m resolution were used to generate Digital Elevation Model (DEM) on an area with low and near Mean Sea Level (MSL) elevation in Johor, Malaysia. The absolute DEM was generated by using the Rational Polynomial Coefficient (RPC) model which was run on ENVI 4.8 software. In order to generate the absolute DEM, 60 Ground Control Pointes (GCPs) with almost vertical accuracy less than 10 meter extracted from topographic map of the study area. The assessment was carried out on uncorrected and corrected DEM by utilizing dozens of Independent Check Points (ICPs). Consequently, the uncorrected DEM showed the RMSEz of ± 26.43 meter which was decreased to the RMSEz of ± 16.49 meter for the corrected DEM after post-processing. Overall, the corrected DEM of ASTER stereo images met the expectations.