QUALITY ASSESSMENT FOR THE FIRST PART OF THE TANDEM-X GLOBAL DIGITAL ELEVATION MODEL

TanDEM-X is an innovative synthetic aperture radar (SAR) mission with the main goal to generate a global and homogeneous digital elevation model (DEM) of the Earth’s land masses. The final DEM product will reach a new dimension of detail with respect to resolution and quality. The absolute horizontal and vertical accuracy shall each be less than 10 m in a 90% confidence interval at a pixel spacing of 12 m. The relative vertical accuracy specification for the TanDEM-X mission foresees a 90% point-to-point error of 2 m (4 m) for areas with predominant terrain slopes smaller than 20% (greater than 20%) within a 1° longitude by 1° latitude cell. The global DEM is derived from interferometric SAR acquisitions performed by two radar satellites flying in close orbit formation. Interferometric performance parameters like the coherence between the two radar images have been monitored and evaluated throughout the mission. In a further step, over 500,000 single SAR scenes are interferometrically processed, calibrated, and mosaicked into a global DEM product which will be completely available in the second half of 2016. This paper presents an up-todate quality status of the single interferometric acquisitions as well as of 50% of the final DEM. The overall DEM quality of these first products promises accuracies well within the specification, especially in terms of absolute height accuracy.

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Vertical accuracy assessment of ALOS World 3D - 30M Digital Elevation Model over northeastern Mindanao, Philippines

2016 IEEE International Geoscience and Remote Sensing Symposium (IGARSS) ◽

10.1109/igarss.2016.7730400 ◽

2016 ◽

Cited By ~ 1

Author(s):

Jojene R. Santillan ◽

Meriam Makinano-Santillan ◽

Ronald M. Makinano

Keyword(s):

Digital Elevation Model ◽

Accuracy Assessment ◽

Digital Elevation ◽

Vertical Accuracy ◽

Elevation Model

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Validating the vertical quality of SRTM digital elevation model of the Mirim Lagoon hydrographic basin

Abstracts of the ICA ◽

10.5194/ica-abs-1-136-2019 ◽

2019 ◽

Vol 1 ◽

pp. 1-2

Author(s):

Andrea Lopes Iescheck ◽

Patricia Andréia Paiola Scalco

Keyword(s):

Statistical Analysis ◽

Digital Elevation Model ◽

Precise Point Positioning ◽

Post Processing ◽

Srtm Dem ◽

Hydrographic Basin ◽

Digital Elevation ◽

Vertical Accuracy ◽

Elevation Model ◽

Srtm Data

Abstract. This work is part of a research project that aims at the automatic determination of knickpoints and the assessment of morphometric and hypsometric parameters of Mirim Lagoon Hydrographic Basin, using Shuttle Radar Topography Mission digital elevation model (SRTM-DEM) and spatial analyses.The analysis of geomorphologic systems is done using computational treatment of data obtained by remote sensing, especially those obtained by SRTM. These data permit the elaboration of a topographic model for the Earth surface and provide a base for studies in several units of geomorphologic analyses (geomorphologic systems), such as hydrographic basins.The most usual technique for derivation of relief morphologic attributes is based on digital elevation models (DEMs) and digital hydrographic nets. Computational routines are applied on those data for acquisition of the hydrography and drainage anomalies. The DEMs and the hydrographic nets must have either morphologic or hydrologic consistency to validate the results obtained in the morphometric analyses.More specifically, this study aims at describing the method and related results regarding the validation of the vertical accuracy of SRTM-DEM through a kinematic positioning based on the Global Navigation Satellite System (GNSS), in the Mirim Lagoon Hydrographic Basin region. Mirim Lagoon Hydrographic Basin is as cross-border basin located on the Atlantic coast of South America, and covers an area of 58,407.78&thinsp;km2, where 47% of this area is in Brazil and 53% in Uruguay.Several studies deal with the validation of Digital Elevation Models (DEMs) and SRTM data using different GNSS surveying methods and receivers. The innovation of this work is the methodology developed to achieve the suitable accuracy for the control points coordinates to validate the SRTM-DEM of Mirim Lagoon Hydrographic Basin. The study used the kinematic relative positioning method with a recording rate of 1 second and without reference stations for post-processing with the precise point positioning (PPP) method. This methodology allowed covering a large area with reference stations being very far from the surveyed region and with different geodetic reference systems (two countries).The methodology entails the GNSS data acquisition and post-processing, the transformation from geometric heights into orthometric heights, the SRTM-DEM mosaic, the extraction of homologous points in the SRTM-DEM and the statistical analyses for validating the model.The study used a GNSS receiver of dual-frequency with recording rate of 1 second to collect a total of 275,916 points with 3D coordinates. Those points were post-processed using the PPP method with the Canadian Spatial Reference System &ndash; Precise Point Positioning (CSRS-PPP), and the ellipsoidal height was converted into orthometric height through the software INTPT geoid. During this work, we used the geopotential model (EGM96) to transform height differences between two countries, Brazil and Uruguay.In order to obtain the SRTM-DEM we used 15 SRTM images, version 3, band C, with a spatial resolution of 1 arcsecond (approximately 30&thinsp;m). These images were individually processed to obtain the Digital Elevation Model Hydrologically Consistent (DEMHC) and to treat the inconsistencies. Afterwards, we created a mosaic with the 15 images.In the statistical analysis we examined the magnitude of absolute errors in the SRTM data. These errors were named discrepancies between the SRTM heights and the heights of GNSS survey points. After the post-processing and the heights conversion, the GNSS survey points were considered accurate and used as a reference for SRTM-DEM validation. The goal of the statistical analysis was to verify if the absolute vertical precision of the DEM data exceeds 16&thinsp;m, according to the precision specifications of the DEM SRTM.Results showed that the vertical mean absolute error of the SRTM-DEM vary from 0.07&thinsp;m to &plusmn;&thinsp;9.9&thinsp;m with average of &minus;0.28&thinsp;m. This vertical accuracy is better than the absolute vertical accuracy value of &plusmn;&thinsp;16&thinsp;m published in the SRTM data specification and validates the SRTM-DEM. Besides that, even considering different slopes and different heights the statistics showed that SRTM-DEM could be validated, in spite of the results for lower and flat area were more accurate than the ones for a higher area with high slope.

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A new 100-m Digital Elevation Model of the Antarctic Peninsula derived from ASTER Global DEM: methods and accuracy assessment

Earth System Science Data ◽

10.5194/essd-4-129-2012 ◽

2012 ◽

Vol 4 (1) ◽

pp. 129-142 ◽

Cited By ~ 49

Author(s):

A. J. Cook ◽

T. Murray ◽

A. Luckman ◽

D. G. Vaughan ◽

N. E. Barrand

Keyword(s):

Digital Elevation Model ◽

Antarctic Peninsula ◽

Accuracy Assessment ◽

Correction Method ◽

Pixel Size ◽

Aster Gdem ◽

Digital Elevation ◽

Vertical Accuracy ◽

Elevation Model ◽

The Antarctic

Abstract. A high resolution surface topography Digital Elevation Model (DEM) is required to underpin studies of the complex glacier system on the Antarctic Peninsula. A complete DEM with better than 200 m pixel size and high positional and vertical accuracy would enable mapping of all significant glacial basins and provide a dataset for glacier morphology analyses. No currently available DEM meets these specifications. We present a new 100-m DEM of the Antarctic Peninsula (63–70° S), based on ASTER Global Digital Elevation Model (GDEM) data. The raw GDEM products are of high-quality on the rugged terrain and coastal-regions of the Antarctic Peninsula and have good geospatial accuracy, but they also contain large errors on ice-covered terrain and we seek to minimise these artefacts. Conventional data correction techniques do not work so we have developed a method that significantly improves the dataset, smoothing the erroneous regions and hence creating a DEM with a pixel size of 100 m that will be suitable for many glaciological applications. We evaluate the new DEM using ICESat-derived elevations, and perform horizontal and vertical accuracy assessments based on GPS positions, SPOT-5 DEMs and the Landsat Image Mosaic of Antarctica (LIMA) imagery. The new DEM has a mean elevation difference of −4 m (&pm; 25 m RMSE) from ICESat (compared to −13 m mean and &pm;97 m RMSE for the original ASTER GDEM), and a horizontal error of less than 2 pixels, although elevation accuracies are lower on mountain peaks and steep-sided slopes. The correction method significantly reduces errors on low relief slopes and therefore the DEM can be regarded as suitable for topographical studies such as measuring the geometry and ice flow properties of glaciers on the Antarctic Peninsula. The DEM is available for download from the NSIDC website: http://nsidc.org/data/nsidc-0516.html (doi:10.5060/D47P8W9D).

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ICESAT VALIDATION OF TANDEM-X I-DEMS OVER THE UK

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsarchives-xli-b4-129-2016 ◽

2016 ◽

Vol XLI-B4 ◽

pp. 129-136 ◽

Cited By ~ 2

Author(s):

L. Feng ◽

J.-P. Muller

Keyword(s):

Slope Aspect ◽

Surface Slope ◽

Grid Spacing ◽

Digital Elevation ◽

X Band ◽

Elevation Data ◽

Vertical Accuracy ◽

Elevation Model ◽

The Uk ◽

Interferometric Sar

From the latest TanDEM-X mission (bistatic X-Band interferometric SAR), globally consistent Digital Elevation Model (DEM) will be available from 2017, but their accuracy has not yet been fully characterised. This paper presents the methods and implementation of statistical procedures for the validation of the vertical accuracy of TanDEM-X iDEMs at grid-spacing of approximately 12.5 m, 30 m and 90 m based on processed ICESat data over the UK in order to assess their potential extrapolation across the globe. The accuracy of the TanDEM-X iDEM in UK was obtained as follows: against ICESat GLA14 elevation data, TanDEM-X iDEM has −0.028±3.654 m over England and Wales and 0.316 ± 5.286 m over Scotland for 12 m, −0.073 ± 6.575 m for 30 m, and 0.0225 ± 9.251 m at 90 m. Moreover, 90 % of all results at the three resolutions of TanDEM-X iDEM data (with a linear error at 90 % confidence level) are below 16.2 m. These validation results also indicate that derivative topographic parameters (slope, aspect and relief) have a strong effect on the vertical accuracy of the TanDEM-X iDEMs. In high-relief and large slope terrain, large errors and data voids are frequent, and their location is strongly influenced by topography, whilst in the low- to medium-relief and low slope sites, errors are smaller. ICESat derived elevations are heavily influenced by surface slope within the 70 m footprint as well as there being slope dependent errors in the TanDEM-X iDEMs.

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EVALUATION DIGITAL ELEVATION MODEL GENERATED BY SYNTHETIC APERTURE RADAR DATA

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xli-b1-57-2016 ◽

2016 ◽

Vol XLI-B1 ◽

pp. 57-62

Author(s):

H. B. Makineci ◽

H. Karabörk

Keyword(s):

Remote Sensing ◽

Digital Elevation Model ◽

Interpolation Method ◽

Digital Elevation Models ◽

European Space Agency ◽

Mountain Area ◽

Synthetic Aperture Radar Data ◽

Radar Images ◽

Digital Elevation ◽

Elevation Model

Digital elevation model, showing the physical and topographical situation of the earth, is defined a tree-dimensional digital model obtained from the elevation of the surface by using of selected an appropriate interpolation method. DEMs are used in many areas such as management of natural resources, engineering and infrastructure projects, disaster and risk analysis, archaeology, security, aviation, forestry, energy, topographic mapping, landslide and flood analysis, Geographic Information Systems (GIS). Digital elevation models, which are the fundamental components of cartography, is calculated by many methods. Digital elevation models can be obtained terrestrial methods or data obtained by digitization of maps by processing the digital platform in general. Today, Digital elevation model data is generated by the processing of stereo optical satellite images, radar images (radargrammetry, interferometry) and lidar data using remote sensing and photogrammetric techniques with the help of improving technology. One of the fundamental components of remote sensing radar technology is very advanced nowadays. In response to this progress it began to be used more frequently in various fields. Determining the shape of topography and creating digital elevation model comes the beginning topics of these areas. It is aimed in this work , the differences of evaluation of quality between Sentinel-1A SAR image ,which is sent by European Space Agency ESA and Interferometry Wide Swath imaging mode and C band type , and DTED-2 (Digital Terrain Elevation Data) and application between them. The application includes RMS static method for detecting precision of data. Results show us to variance of points make a high decrease from mountain area to plane area.

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Ice Surface Topography Digital Elevation Model by Interferometric SAR Method

GIScience & Remote Sensing ◽

10.2747/1548-1603.45.3.306 ◽

2008 ◽

Vol 45 (3) ◽

pp. 306-329 ◽

Cited By ~ 1

Author(s):

John Lin

Keyword(s):

Surface Topography ◽

Digital Elevation Model ◽

Ice Surface ◽

Digital Elevation ◽

Elevation Model ◽

Interferometric Sar

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VALIDATION OF THE ASTER GLOBAL DIGITAL ELEVATION MODEL VERSION 3 OVER THE CONTERMINOUS UNITED STATES

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsarchives-xli-b4-143-2016 ◽

2016 ◽

Vol XLI-B4 ◽

pp. 143-148 ◽

Cited By ~ 9

Author(s):

D. Gesch ◽

M. Oimoen ◽

J. Danielson ◽

D. Meyer

Keyword(s):

United States ◽

Land Cover ◽

Digital Elevation Model ◽

Ground Level ◽

Land Cover Type ◽

Mean Error ◽

Digital Elevation ◽

The Mean ◽

Vertical Accuracy ◽

Elevation Model

The ASTER Global Digital Elevation Model Version 3 (GDEM v3) was evaluated over the conterminous United States in a manner similar to the validation conducted for the original GDEM Version 1 (v1) in 2009 and GDEM Version 2 (v2) in 2011. The absolute vertical accuracy of GDEM v3 was calculated by comparison with more than 23,000 independent reference geodetic ground control points from the U.S. National Geodetic Survey. The root mean square error (RMSE) measured for GDEM v3 is 8.52 meters. This compares with the RMSE of 8.68 meters for GDEM v2. Another important descriptor of vertical accuracy is the mean error, or bias, which indicates if a DEM has an overall vertical offset from true ground level. The GDEM v3 mean error of −1.20 meters reflects an overall negative bias in GDEM v3. The absolute vertical accuracy assessment results, both mean error and RMSE, were segmented by land cover type to provide insight into how GDEM v3 performs in various land surface conditions. While the RMSE varies little across cover types (6.92 to 9.25 meters), the mean error (bias) does appear to be affected by land cover type, ranging from −2.99 to +4.16 meters across 14 land cover classes. These results indicate that in areas where built or natural aboveground features are present, GDEM v3 is measuring elevations above the ground level, a condition noted in assessments of previous GDEM versions (v1 and v2) and an expected condition given the type of stereo-optical image data collected by ASTER. GDEM v3 was also evaluated by differencing with the Shuttle Radar Topography Mission (SRTM) dataset. In many forested areas, GDEM v3 has elevations that are higher in the canopy than SRTM. The overall validation effort also included an evaluation of the GDEM v3 water mask. In general, the number of distinct water polygons in GDEM v3 is much lower than the number in a reference land cover dataset, but the total areas compare much more closely.

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On the Vertical Accuracy of the ALOS World 3D-30m Digital Elevation Model

10.20944/preprints201708.0081.v1 ◽

2017 ◽

Author(s):

Çaglar Bayık ◽

Kazimierz Becek ◽

Çetin Mekik ◽

Mustafa Özendi

Keyword(s):

Digital Elevation Model ◽

Reference Data ◽

Accuracy Assessment ◽

Reference Dataset ◽

Digital Elevation ◽

The World ◽

Vertical Accuracy ◽

Longitudinal Profiles ◽

Elevation Model ◽

Resolution Data

The digital elevation model (DEM) is one of the key geospatial datasets used in many fields of engineering and science for countless applications. In this contribution, we assess the vertical accuracy of the Advanced Land Observing Satellite (ALOS) World 3D-30m (AW3D30) DEM using the runway method (RWYM). The RWYM utilizes the longitudinal profiles of runways which are reliable and ubiquitous reference data. A reference dataset used in this project consists of 36 runways located at various points throughout the world. The same dataset was previously used to test the accuracy of WorldDEMTM.  Our study indicates that AW3D30 has a remarkably high RMSE of 1.78 m (one σ). However, while analyzing the results, it has become apparent that it also contains a widespread elevation anomaly. We conclude that this anomaly is the result of uncompensated sensor noise and the data processing algorithm (downsampling of the higher resolution data). We believe that this issue should be communicated to the user community. Also, we would like to note that the traditional accuracy assessment of a DEM, e.g., statistical assessment of the elevation differences = model – reference, does not allow for identification of these type of anomalies in a DEM.

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Geração de Modelo Digital de Elevação utilizando dados do SRTM como subsídio ao planejamento e gestão territorial do município de Lucena(PB)/Generation of Digital Elevation Model using SRTM data as grant to territorial planning and management (...)

Caderno de Geografia ◽

10.5752/p.2318-2962.2016v26n45p151 ◽

2015 ◽

Vol 26 (45) ◽

pp. 151

Author(s):

Erika Rodrigues Dias

Keyword(s):

Digital Elevation Model ◽

Three Dimensional ◽

Shuttle Radar Topography Mission ◽

Google Earth ◽

Detailed Knowledge ◽

Radar Images ◽

Territorial Planning ◽

Planning And Management ◽

Digital Elevation ◽

Elevation Model

Uma das grandes preocupações da atualidade encontra-se no uso racional das terras, conciliando aspectos sociais, econômicos e ambientais tornando necessário o planejamento territorial através de um conhecimento detalhado da superfície territorial. Dessa forma, é de fundamental importância a representação do terreno. Assim, este trabalho teve por objetivo gerar um modelo digital de elevação – MDE, utilizando imagens de radar SRTM com a finalidade de servir como subsídio à gestão e planejamento territorial. Os materiais utilizados nesse trabalho foram imagens de radar da missão Shuttle Radar Topography Mission – SRTM, imagens obtidas do Google Earth e softwares específicos. Como resultados foram gerados diversos produtos cartográficos que possibilitaram o reconhecimento territorial do município como os mapas de hipsometria e clinografia da área em estudo e a representação tridimensional do relevo visando servir como subsídio à gestão territorial e planejamento do meio físico.Palavras-Chave: Modelo Digital de Elevação, SRTM, Geotecnologias.AbstractA major concern of today is in the rational use of land, combining social, economic and environmental aspects making it necessary to territorial planning with a detailed knowledge of land area. Thus, it is fundamental to representation of the terrain. Thus, this study aimed to generate a digital elevation model - MDE using SRTM radar images in order to serve as a resource management and territorial planning. The materials used in this work were the mission radar images Shuttle Radar Topography Mission - SRTM, images obtained from Google Earth and specific software. The results were generated several cartographic products enabled the territorial recognition of the city as hypsometry maps and clinografia of the study area and the three-dimensional relief representation to serve as subsidy for territorial planning and management of the physical environment. Keywords:Digital Elevation Model, SRTM, Geotechnology.

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