Assessment of open source digital elevation models (SRTM-30, ASTER, ALOS) for erosion processes modeling

Abstract

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.

Features of Ecological Geomorphometry as a Prospective Field of Study, Its Main Concepts and Methods

“…The utility of spatial ecological models based on terrain attributes has significantly increased in recent decades due to the advance of accessible high-quality digital elevation models (DEMs) and technologies of their processing and analysis. Several choices are already available for the free of charge DEMs with near-global coverage and spatial resolution fine enough for the purposes of the detailed analysis of land surface processes (Kovalchuk, Luk`yanchuk & Bohdanets, 2019). For instance, newly versions of SRTM DEM and ALOS DEM have horizontal resolution of 1 arcsecond which is roughly equivalent to 30 m in projected units (Jarvis et al, 2008;Takaku, Tadono & Tsutsui, 2014).…”

“…Yet another product is ASTER GDEM with 30-meter spatial resolution, covering land surface between 83°N and 83°S. However, its accuracy is regarded as somewhat inferior, comparing with aforementioned SRTM and ALOS DEMs (Kovalchuk et al, 2019).…”

Análisis comparativo de los modelos digitales de elevaciones SRTM y MDE-Ar 2.0 para la identificación de áreas de peligrosidad por inundaciones y anegamientos en un área urbana de llanura

“…En general estos aportes tienen como objetivo comparar estas superficies con puntos de control terrestre correspondientes al área de interés. Asimismo, han demostrado que, respecto a la medición de la precisión de los MDE el cálculo de las diferencias altimétricas con base en dichos puntos, el cálculo de Error Medio Cuadrático y el análisis de residuos, significan indicadores apropiados para estimar la precisión de los MDE (Felicísimo, 1994;Pacheco y Barrios, 2004;Presutti, 2009;Díaz et al, 2010;Lencinas y Díaz, 201;Burgos, 2012;Muñoz, 2013;Garzón Barrero et al, 2013;Hu et al, 2017;Li y Zhao, 2018;Florinsky et al, 2018;Florinsky et al, 2019, Kovalchuk et al, 2019; Kilinç y Alazaiza, 2019).…”

“…Si bien no existen diferencias marcadas entre los resultados mencionados hasta aquí, el MDE-Ar 2.0 se coloca en una mejor posición en términos de calidad ya que posee menor EMC y la media de diferencias de alturas resulta también menor que el SRTM. Esto también fue señalado por otros autores que han comparado al MDE ALOS (insumo básico del MDE-Ar 2.1) con otras superficies, determinando que éste posee mejor precisión altimétrica entre los modelos globales (Li y Zhao, 2018;Florinsky et al, 2019, Kovalchuk et al, 2019Kilinç y Alazaiza, 2019 pág. 54 60 -26° 35' 55.3'' -59° 18' 57.2'' 75,0 78 -3,0 8,9 78 -3,0 8,9 61 -26° 35' 45.6'' -59° 27' 39.5'' 73,0 76 -3,0 9,2 76 -3,0 9,2 62 -26° 42' 45.6'' -59° 13' 17.2'' 68,1 71 -2,9 8,5 72 -3,9 15,3 63 -26° 40' 00.7'' -59° 16' 55.7'' 70,4 73 -2,6 6,5 73 -2,6 6,5 64 -26° 27' 22.2'' -59° 20' 58.6'' 77,4 82 -4,6 21,3 78 -0,6 0,4…”

Otimização de Modelos Digitais de Elevação para a Obtenção de Variáveis Geomorfológicas e Hidrológicas: Avaliação da Convolução Bidimensional sobre os Produtos ALOS, ASTER-GDEM e SRTM

“…Nos últimos anos, diversos estudos utilizaram os MDE ALOS, ASTER-GDEM e SRTM para obtenção de variáveis morfométricas, como exemplo citam-se: Buitrago & Martínez (2016); Chagas et al (2009); Carmo et al (2015); Khal et al (2020); Kovalchuk, Lukianchuk & Bogdanets (2019). No entanto, apesar da vasta aplicação, esses MDE não estão livres de erros, o que pode interferir na precisão das variáveis geomorfológicas e hidrológicas deles derivadas.…”