The Use of Spherical Statistics to Analyze Digital Elevation Models: An Example From LIDAR and ASTER GDEM

The relief has a major impact on the landscape`s hydrological, geomorphological and biological processes. Many geographic information systems used elevation data as the primary data for analysis, modeling, etc. A digital elevation model (DEM) is a modern representation of the continuous variations of relief over space in digital form. Digital Elevation Models (DEMs) are important source for prediction of soil erosion parameters. The potential of global open source DEMs (SRTM, ASTER, ALOS) and their suitability for using in modeling of erosion processes are assessed in this study. Shumsky district of Ternopil region, which is located in the Western part of Ukraine, is the area of our study. The soils of Shumsky district are adverselyaffected by erosion processes. The analysis was performed on the basis of the characteristics of the hydrological network and relief. The reference DEM was generated from the hypsographic data(contours) on the 1:50000 topographical map series compiled by production units of the Main Department of Geodesy and Cartography under the Council of Ministers. The differences between the reference DEM and open source DEMs (SRTM, ASTER and ALOS) are examined. Methods of visual detection of DEM defects, profiling, correlation, and statistics were used in the comparative analysis. This research included the analysis oferrors that occurred during the generation of DEM. The vertical accuracy of these DEMs, root mean square error (RMSE), absolute and relative errors, maximum deviation, and correlation coefficient have been calculated. Vertical accuracy of DEMs has been assessed using actual heights of the sample points. The analysis shows that SRTM and ALOS DEMs are more reliable and accurate than ASTER GDEM. The results indicate that vertical accuracy of DEMs is 7,02m, 7,12 m, 7,60 mand 8,71 m for ALOS, SRTM 30, SRTM 90 and ASTER DEMs respectively. ASTER GDEM had the highest absolute, relative and root mean square errors, the highest maximum positive and negative deviation, a large difference with reference heights, and the lowest correlation coefficient. Therefore, ASTER GDEM is the least acceptable for studying the intensity and development of erosion processes. The use of global open source DEMs, compared with the vectorization of topographic maps,greatly simplifies and accelerates the modeling of erosion processes and the assessment of the erosion risk in the administrative district.

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ALTIMETRY ASSESSMENT OF ASTER GDEM v2 AND SRTM v3 DIGITAL ELEVATION MODELS: A CASE STUDY IN URBAN AREA OF BELO HORIZONTE, MG, BRAZIL

Boletim de Ciências Geodésicas ◽

10.1590/s1982-21702017000400043 ◽

2017 ◽

Vol 23 (4) ◽

pp. 654-668 ◽

Cited By ~ 1

Author(s):

Josyceyla Duarte Morais ◽

Thaísa Santos Faria ◽

Marcos Antonio Timbó Elmiro ◽

Marcelo Antonio Nero ◽

Archibald de Araujo Silva ◽

...

Keyword(s):

Remote Sensing ◽

Reference Model ◽

Digital Elevation Models ◽

Evaluation Study ◽

Aster Gdem ◽

Digital Elevation ◽

Class B ◽

Positive Linear Correlation ◽

Belo Horizonte ◽

Model Residuals

Abstract: This work is an altimetry evaluation study involving Digital Elevation Models ASTER GDEM version 2 and SRTM version 3. Both models are readily available free of charge, however as they are built from different remote sensing methods it is also expected that they present different data qualities. LIDAR data with 25 cm vertical accuracy were used as reference for assessment validation. The evaluation study, carried out in urbanized area, investigated the distribution of the residuals and the relationship between the observed errors with land slope classes. Remote sensing principles, quantitative statistical methods and the Cartographic Accuracy Standard of Digital Mapping Products (PEC-PCD) were considered. The results indicated strong positive linear correlation and the existence of a functional relationship between the evaluated models and the reference model. Residuals between -4.36 m and 3.11 m grouped 47.7% of samples corresponding to ASTER GDEM and 63.7% of samples corresponding to SRTM. In both evaluated models, Root Mean Square Error values increased with increasing of land slope. Considering 1: 50,000 mapping scale the PEC-PCD classification indicated class B standard for SRTM and class C for ASTER GDEM. In all analyzes, SRTM presented smaller altimetry errors compared to ASTER GDEM, except in areas with steep relief.

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Uso de Modelo Digital de Elevação Gerados a partir do ASTER GDEM e SRTM para Caracterização da Rede de Drenagem do Município de Renascença no Sudoeste do Estado do Paraná (Use of Digital Elevation Model Generated from the SRTM and ASTER GDEM for...)

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v4i2.232705 ◽

2011 ◽

Vol 4 (2) ◽

pp. 365 ◽

Cited By ~ 1

Author(s):

Julio Caetano Tomazoni ◽

Elisete Guimarães ◽

Tayoná Cristina Gomes ◽

Taisller Guimarães da Silva

Keyword(s):

Digital Elevation Model ◽

Digital Elevation Models ◽

Drainage System ◽

Drainage Network ◽

Aster Data ◽

Aster Gdem ◽

Drainage Networks ◽

Digital Elevation ◽

Elevation Model ◽

Spot 5

Este trabalho avalia a adequação do uso de modelos digitais de elevação, provenientes da manipulação de dados altimétricos da missão SRTM e do instrumento imageador ASTER, para atualização de mapas da rede de drenagem do município de Renascença PR. Para caracterização da rede de drenagem a partir de dados SRTM e ASTER utilizou-se o software SPRING 5.1.7. A rede hidrográfica, obtida por esses dois métodos foi cruzada com a malha hidrográfica extraída de cartas geográficas do exército e imagens ortorretificadas do satélite SPOT 5. Os resultados demonstram que a rede de drenagem, obtida a partir de dados SRTM e ASTER, não é satisfatória por não determinar a grande maioria dos cursos d’água de primeira e segunda ordens. Já os de terceira, quarta e quinta ordens, que são identificados, na grande maioria estão localizados fora do curso real encontrados pelas cartas do exército e imagens ortorretificadas. Os dados demonstram que a vegetação das matas ciliares são captadas pelo SRTM e ASTER e interferem nas variações de altitude e por conseguinte no mau delineamento das redes de drenagem.Palavras chaves – Rede de drenagem; hidrografia; modelos digitais de elevação; SRTM, ASTER. Use of Digital Elevation Model Generated from the SRTM and ASTER GDEM for Characterization of Drainage ABSTRACTThis paper assesses the suitability of using digital elevation models, resulting from manipulation of altimetric mission SRTM and ASTER instrument, to update maps of the drainage network in the municipality of Renaissance PR. To characterize the drainage network from SRTM and ASTER data used the software SPRING 5.1.7. The hydrographic network, obtained by these two methods was crossed with a mesh extracted from hydrographic maps of the army and orthorectified images of the SPOT 5 satellite. The results show that the drainage system, derived from SRTM and ASTER data is not satisfactory because they do not determine the vast majority of streams of first and second orders. Already the third, fourth and fifth orders, which are identified in the vast majority are located outside the actual course of the letters found by the army and orthorectified images. The data show that the riparian vegetation are acquired by SRTM and ASTER and interfere with the variations in altitude and therefore the bad design of drainage networks. Keywords - Drainage network; hydrography; digital elevation models; SRTM; ASTER GDEM.

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Avaliação da Acurácia Vertical dos Modelos Digitais de Elevação SRTM, ALOS World 3D e ASTER GDEM: Um Estudo de Caso no Vale dos Vinhedos, RS – Brasil

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v13.5.p2255-2268 ◽

2020 ◽

Vol 13 (5) ◽

pp. 2255

Author(s):

Jorge Antônio Viel ◽

Kátia Kellem da Rosa ◽

Cláudio Wilson Mendes Junior

Keyword(s):

Spatial Resolution ◽

Digital Elevation Models ◽

Pearson Correlation ◽

Mean Square ◽

Class A ◽

Aster Gdem ◽

Digital Elevation ◽

The Mean ◽

Vertical Accuracy

Este estudo tem como objetivo avaliar a acurácia vertical dos Modelos Digitais de Elevação (MDEs) SRTM v.3, ALOS World 3D e ASTER GDEM v.2 na região da denominação de origem Vale dos Vinhedos, RS. Para tanto, os dados desses MDEs, com resolução espacial de 30 m, foram comparados com os de um MDE fotogramétrico com resolução espacial de 5 m no terreno, por meio de análises de regressão e correlação linear, e de perfis topográficos derivados desses modelos. O Padrão de Exatidão Cartográfica dos Produtos Cartográficos Digitais (PEC-PCD) de cada MDE foi analisado, para identificar a escala máxima de seu uso em estudos morfométricos, nas escalas 1:25.000, 1:50.000 e 1:100.000, por meio de cálculos da Tolerância Vertical e do Erro Médio Quadrático (EMQ). Os MDEs SRTM v.3 e ASTER GDEM v.2 atenderam o PEC-PCD altimétrico classe A na escala 1:100.000. Diferentemente do MDE ALOS World 3D que enquadrou-se na classe B para a escala de 1:100.000. Todos os modelos, na escala 1:50.000, enquadraram-se na classe D, enquanto que na escala 1:25.000 não houve enquadramento. O MDE SRTM v.3 foi o que apresentou melhores resultados morfométricos e o maior coeficiente de correlação de Pearson (r=0,995). Todos os MDEs avaliados neste estudo apresentaram morfologia próxima a do MDE fotogramétrico. Portanto, recomenda-se o uso de todos os MDEs analisados em estudos morfométricos da área de estudo, sendo necessário observar o objetivo do trabalho, bem como a escala de análise e a apresentação desses dados. Evaluation of the Vertical Acuracy of Digital Elevation Models SRTM, ALOS WORLD 3D and ASTER GDEM: a case study in Vale dos Vinhedos, RS - Brazil A B S T R A C TThis work aims to evaluate the vertical accuracy of the digital elevation models (DEMs) SRTM v.3, Alos World 3D and ASTER GDEM v.2 in Vale dos Vinhedos designation of origin (DO) region, RS. Thus, the DEM data with 30 m of the spatial resolution were compared with photogrammetric DEM data with 5 m of the spatial resolution by linear regression and correlation analyzes, and also, topographic profiles carried out with these models. The Cartographic Accuracy Standard (PEC) of each DEM was analyzed to identify the maximum scale for morphometric application, in scales 1:25.000, 1:50.000 and 1:100.000, by calculations of Vertical Tolerance and the Mean Square Error (MSE). All DEMs. All the models studied were classified in class A for the 1:100,000 scale, and for the 1:50,000 scale the analyzed models were classified in class C, while in 1:25.000 scale doesn´t have application. The DEM SRTM v.3 presented smaller altimetry errors compared to ASTER GDEM and Alos World 3D, as for mophometric analysis and Pearson correlation coefficient (r=0,995). It is worth mentioning that all models analyzed are statistically and morphologically close. Therefore, they can be used to conduct several studies, however it is necessary to have in mind the goal of the work, and the scale of analysis and presentation.Keywords: Vertical accuracy, SRTM v.3, Alos World 3D, ASTER GDEM

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ASSESSMENT OF REFERENCE HEIGHT MODELS ON QUALITY OF TANDEM-X DEM

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

10.5194/isprsarchives-xl-1-w5-463-2015 ◽

2015 ◽

Vol XL-1-W5 ◽

pp. 463-466 ◽

Cited By ~ 2

Author(s):

S. Mirzaee ◽

M. Motagh ◽

H. Arefi

Keyword(s):

High Resolution ◽

Digital Elevation Models ◽

Slant Range ◽

Aster Gdem ◽

Digital Elevation ◽

X Band ◽

Topography Model ◽

Previous Step

The aim of this study is to investigate the effect of various Global Digital Elevation Models (GDEMs) in producing high-resolution topography model using TanDEM-X (TDX) Coregistered Single Look Slant Range Complex (CoSSC) images. We selected an image acquired on Jun 12<sup>th</sup>, 2012 over Doroud region in Lorestan, west of Iran and used 4 external digital elevation models in our processing including DLR/ASI X-SAR DEM (SRTM-X, 30m resolution), ASTER GDEM Version 2 (ASTER-GDEMV2, 30m resolution), NASA SRTM Version 4 (SRTM-V4, 90m resolution), and a local photogrammetry-based DEM prepared by National Cartographic Center (NCC DEM, 10m resolution) of Iran. InSAR procedure for DEM generation was repeated four times with each of the four external height references. The quality of each external DEM was initially assessed using ICESat filtered points. Then, the quality of, each TDX-based DEM was assessed using the more precise external DEM selected in the previous step. Results showed that both local (NCC) DEM and SRTM X-band performed the best (RMSE< 9m) for TDX-DEM generation. In contrast, ASTER GDEM v2 and SRTM C-band v4 showed poorer quality.

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