scholarly journals Satellite-Derived Topography and Morphological Evolution around Authie Macrotidal Estuary (France)

2021 ◽  
Vol 9 (12) ◽  
pp. 1354
Author(s):  
Philippe Bagot ◽  
Nicolas Huybrechts ◽  
Philippe Sergent
Keyword(s):  
Morphological Evolution ◽  
Estuarine System ◽  
Northern Coast ◽  
Topographic Map ◽  
Digital Elevation ◽  
Severe Erosion ◽  
Elevation Model ◽  
Landsat Satellite ◽  
Temporal Coverage ◽  
Sentinel 2

The wide spatial and temporal coverage of remotely sensing images is an essential asset to analyze the morphological behaviour of fast-changing coastal environments such as estuarine systems. This paper investigates the reliability of intertidal topography mapping around the Authie Bay, a macrotidal estuarine system located on the northern coast of France. A Satellite-Derived Topography technique is developed by relating the green band reflectance of Sentinel-2 images to rapid variations in topography. This method is well suited to small sedimentary structures of the coastal zone with a 0.30 to 0.35 m height accuracy of the constructed Digital Elevation Model (DEM). For the more complex estuarine configuration, the waterline method was applied and resulted in the construction of DEMs with a height accuracy of 0.35 to 0.38 m. Video animations and records of Authie meander positions along transects are created from Sentinel-2 and Landsat satellite archives (1984–2020). These materials allow to highlight a sedimentation phase at the east side of the spit since 2015. It constrains the main channel towards the eastern bank, thus promoting coastal erosion. The monitoring of a severe erosion phase throughout 2019 shows a 130 m retreat of the coastline. Topographic map differentiation led to the detection of a sedimentation anomaly upstream of the bay, probably linked to this erosion event.

Quality Assessment of Globally Available Digital Elevation Model (DEM) for Mountainous Region

2021 ◽  
Vol 5 (1) ◽  
pp. 11-21
Author(s):  
Sangay Gyeltshen ◽  
Krisha Kumar Subedi ◽  
Laylo Zaridinova Kamoliddinovna ◽  
Jigme Tenzin
Keyword(s):  
Digital Elevation Model ◽  
Vertical Displacement ◽  
Satellite System ◽  
Topographic Map ◽  
Alos Palsar ◽  
Aster Gdem ◽  
Digital Elevation ◽  
The Government ◽  
Elevation Model ◽  
The Individual

The study assessed the accuracies of globally available Digital Elevation Models (DEM’s) i.e., SRTM v3, ASTER GDEM v2 and ALOS PALSAR DEM with respect to Topo-DEM derived from topographic map of 5m contour interval. 100 ground control points of the elevation data were collected with the help of kinematic hand held GNSS (Global Navigation Satellite System), randomly distributed over the study area. The widely used RMSE statistic, NCC correlation and sub-pixel-based approach were applied to evaluate the erroneous, correlation, horizontal and vertical displacement in terms of pixels for the individual Digital Elevation Model. Following these evaluations, SRTM DEM was found to be highly accurate in terms of RMSE and displacement compared to other DEMs. This study is intended to provide the researchers, GIS specialists and the government agencies dealing with remote sensing and GIS, a basic clue on accuracy of the DEMs so that the best model can be selected for application on various purposes of the similar region.

scholarly journals THE DESIGN AND PRODUCT OF NATIONAL 1:1000000 CARTOGRAPHIC DATA OF TOPOGRAPHIC MAP

2016 ◽  
Vol XLI-B2 ◽  
pp. 245-249
Author(s):  
Guizhi Wang
Keyword(s):  
Line Graph ◽  
Topographic Map ◽  
Dynamic Update ◽  
Structure Database ◽  
Database Structure ◽  
Digital Elevation ◽  
Mapping Technology ◽  
Elevation Model ◽  
Digital Elevation Model Data ◽  
Information Database

National administration of surveying, mapping and geoinformation started to launch the project of national fundamental geographic information database dynamic update in 2012. Among them, the 1:50000 database was updated once a year, furthermore the 1:250000 database was downsized and linkage-updated on the basis. In 2014, using the latest achievements of 1:250000 database, comprehensively update the 1:1000000 digital line graph database. At the same time, generate cartographic data of topographic map and digital elevation model data. This article mainly introduce national 1:1000000 cartographic data of topographic map, include feature content, database structure, Database-driven Mapping technology, workflow and so on.

scholarly journals Environmental monitoring of soil pollution in urban areas (a case study from Heraklion city, Central Crete, Greece)

2017 ◽  
Vol 47 (2) ◽  
pp. 963
Author(s):  
E. Kokinou ◽  
C. Belonaki ◽  
D. Sakadakis ◽  
K. Sakadaki
Keyword(s):  
Magnetic Susceptibility ◽  
Urban Areas ◽  
Magnetic Measurements ◽  
Topographic Map ◽  
Near Surface ◽  
Thermomagnetic Analysis ◽  
Geological Features ◽  
Digital Elevation ◽  
Elevation Model

Main scope of the present study is to combine topographic and geological data, magnetic susceptibility and thermomagnetic analysis in order to investigate the magnetic properties of the near surface soils in possible polluted urban areas. For this purpose, a power plant with a dense traffic net around it, located in the NW section of Heraklion city in Crete was selected to be the study area. Surface soil samples have been collected from the area under investigation and they were analyzed in order to estimate the spatial distribution of the magnetic susceptibility. Loci of high values of the magnetic susceptibility within the study area gave rise to further proceed to thermomagnetic analysis of the selected samples. GIS techniques were used for mapping the magnetic measurements on the various topographic and geological features of the area. The digital elevation model was created by the digitization of the topographic map contours (1:5000 scale maps). The combination of the above techniques indicate high values of the magnetic susceptibility especially in the northeastern part of the investigated area, possibly related to pollution due to the presence of heavy metals.

scholarly journals Potential of Sentinel-2 Images for Estimating of Soil Resistivity over Agricultural Fields

Proceedings ◽  
2019 ◽  
Vol 24 (1) ◽  
pp. 18
Author(s):  
Remy Fieuzal ◽  
Vincent Bustillo ◽  
David Collado ◽  
Gerard Dedieu
Keyword(s):  
Electrical Resistivity ◽  
Near Infrared ◽  
Soil Layers ◽  
Digital Elevation ◽  
Combined Use ◽  
Input Variables ◽  
Elevation Model ◽  
High Level ◽  
Sentinel 2 ◽  
Soil Electrical Resistivity

The aim of this study is to assess the possibilities of the VNIR (Visible and Near InfraRed) and SWIR (Short Wavelength InfraRed) satellite data for estimating intra-plot patterns of soil electrical resistivity consistent with ground measurements. The methodology is based on optical reflectances that constitute the input variables of random forest, alone or in combination with parameters derived from a digital elevation model (DEM). Over a field located in southwestern France, the results show high level of accuracy for the 0–50 and 0–100 cm soil layers (with R² of 0.69 and 0.59, and a relative RMSE of 18% and 16%, respectively), the performances being lower for the 0–170 cm layer (R² of 0.39, relative RMSE of 20%). The combined use of optical reflectances with parameters derived from the DEM slightly improves the performances, whatever the considered layer. The influence of each reflectance on soil electrical resistivity estimates is finally analyzed, showing that the wavelengths acquired in the SWIR have a relative higher importance than VNIR reflectance.

scholarly journals CARTOGRAPHY OF MOROCCAN ARGAN TREE USING COMBINED OPTICAL AND SAR IMAGERY INTEGRATED WITH DIGITAL ELEVATION MODEL

2021 ◽  
Vol XLVI-4/W5-2021 ◽  
pp. 211-217
Author(s):  
E. Elmoussaoui ◽  
A. Moumni ◽  
A. Lahrouni
Keyword(s):  
Machine Learning ◽  
Time Series ◽  
Digital Elevation Model ◽  
Optical Data ◽  
Support Vector ◽  
Ground Truth Data ◽  
Argan Tree ◽  
Digital Elevation ◽  
Elevation Model ◽  
Sentinel 2

Abstract. Forest tree species mapping became easier due to the global availability of high spatio-temporal resolution images acquired from multiple sensors. Such data can lead to better forest resources management. Machine-learning pixel based analysis was performed to multi-spectral Sentinel-2 and Synthetic Aperture Radar Sentinel-1 time series integrated with Digital Elevation Model acquired over Argan forest of Essaouira province, Morocco. The argan tree constitutes a fundamental resource for the populations of this arid area of Morocco. This research aims to use the potential of the combination of multi-sensor data to detect, map and identify argan tree from other forest species using three Machine Learning algorithms: Support Vector Machine (SVM), Maximum Likelihood (ML) and Artificial Neural Networks (ANN). The exploited datasets included Sentinel-1 (S1), Sentinel-2 (S2) time series, Shuttle Radar Topographic Missing Digital Elevation Model (DEM) layer and Ground truth data. We tested several sets of scenarios, including single S1 derived features, single S2 time series and combined S1 and S2 derived layers with DEM scene acquisition. The best results (overall accuracy OA and Kappa coefficient K) obtained from time series of optical data (NDVI): OA = 86.87%, K = 0.84, from time series of SAR data (VV+VH/VV): OA = 45.90%, K = 0.36, from the combination of optical and SAR time series (NDVI+VH+DEM): OA = 93.01%, K = 0.914, and from the fusion of optical time series and DEM layer (NDVI+DEM): OA = 93.25%, K = 0.91. These results indicate that single-sensor (S2) integrated with the DEM layer led us to obtain the highest classification results.

scholarly journals Quantitative Analysis of Different Environmental Factor Impacts on Land Cover in Nisos Elafonisos, Crete, Greece

2020 ◽  
Vol 17 (18) ◽  
pp. 6437
Author(s):  
Mohamed Elhag ◽  
Silvena Boteva
Keyword(s):  
Land Use ◽  
Environmental Factors ◽  
Land Cover ◽  
Remote Sensing Data ◽  
Mediterranean Ecosystems ◽  
Land Use Land Cover ◽  
Routine Work ◽  
Digital Elevation ◽  
Elevation Model ◽  
Sentinel 2

Land Cover monitoring is an essential task for a better understanding of the ecosystem’s dynamicity and complexity. The availability of Remote Sensing data improved the Land Use Land Cover mapping as it is routine work in ecosystem management. The complexity of the Mediterranean ecosystems involves a complexity of the surrounding environmental factors. An attempt to quantitatively investigate the interdependencies between land covers and affected environmental factors was conducted in Nisos Elafonisos to represent diverse and fragile coastal Mediterranean ecosystems. Sentinel-2 (MSI) sensor and ASTER Digital Elevation Model (DEM) data were used to classify the LULC as well as to draw different vegetation conditions over the designated study area. DEM derivatives were conducted and incorporated. The developed methodology is intended to assess the land use land cover for different practices under the present environmental condition of Nisos Elafonisos. Supervised classification resulted in six different land cover clusters and was tested against three different environmental clusters. The findings of the current research pointed out that the environmental variables are independent and there is a vertical distribution of the vegetation according to altitude.

Topographic Map Update of Esan Central LGA, Edo State, Nigeria, Using SPOT-5 and ASTER LiDAR Data

2014 ◽  
Vol 1 (1) ◽  
pp. 52-69
Author(s):  
S.O. Ogedegbe
Keyword(s):  
Spatial Data ◽  
Digital Terrain Model ◽  
Topographic Maps ◽  
Lidar Data ◽  
Topographic Map ◽  
Terrain Model ◽  
Digital Elevation ◽  
Système D’Information ◽  
Elevation Model ◽  
Spot 5

This study examines the effectiveness and accuracy of SPOT-5 and ASTER LiDAR data satellite images, Global Pos1t1on1ng System (GPS), Digital Terrain Model (DTM), and Geographic Information System (GIS) in carrying out a revision of Nigerian topographic maps at the scale of 1:50,000. The data for the study were collected by extraction of relevant spatial data from the 1964 topographic map, delineation and interpretation of 2009 SPOT-5 data, and field surveys. The landscape changes extracted from SPOT- 5 were used to update the topographic base map and to determine the nature and direction of changes that have taken place in the study area. The findings revealed that changes have occurred in both cultural and relief features over time. The coefficient of correlation and t-test was calculated to show that changes in point, linear and areal features are significant. Also significant were the planh11etric and height accuracies of the revised map. The study shows that satellite data especially SPOT-5 is useful for the revision of topographic maps at scales of 1:50,000 and even larger. And, high-resolution remote sensing at Sm and ASTER data (30m) with GPS (±1.9m) can be used to c.reate a digital elevation model (DEM) on the map which is an essential dataset for complete revision. Cette étude examine l'efficacité et la précision des images satellites de données SPOT-5 et ASTER LiDAR, du système de positionnement global (GPS), du modèle numérique de terrain (MNT) et du système d'information géographique (SIG) pour effectuer une révision des cartes topographiques nigérianes au échelle de 1:50 000. Les données de l'étude ont été recueillies par extraction de données spatiales pertinentes à partir de la carte topographique de 1964, délimitation et interprétation des données SPOT-5 de 2009 et relevés de terrain. Les changements de paysage extraits de SPOT-5 ont été utilisés pour mettre à jour le fond de carte topographique et pour déterminer la nature et la direction des changements qui ont eu lieu dans la zone d'étude. Les résultats ont révélé que des changements se sont produits dans les caractéristiques culturelles et du relief au fil du temps. Le coefficient de corrélation et le test t ont été calculés pour montrer que les changements dans les caractéristiques ponctuelles, linéaires et aréales sont significatifs. Les précisions planimétriques et altimétriques de la carte révisée étaient également importantes. L'étude montre que les données satellitaires, en particulier SPOT-5, sont utiles pour la révision des cartes topographiques à des échelles de 1:50 000 et même plus. De plus, la télédétection haute résolution aux données Sm et ASTER (30 m) avec GPS (± 1,9 m) peut être utilisée pour créer un modèle d'élévation numérique (DEM) sur la carte qui est un ensemble de données essentiel pour une révision complète.

scholarly journals Progress in the Reconstruction of Terrain Relief Before Extraction of Rock Materials—The Case of Liban Quarry, Poland

2020 ◽  
Vol 12 (10) ◽  
pp. 1548 ◽  
Author(s):  
Roksana Zarychta ◽  
Adrian Zarychta ◽  
Katarzyna Bzdęga
Keyword(s):  
Open Pit ◽  
Open Pit Mining ◽  
Topographic Map ◽  
Estimation Errors ◽  
Mining Areas ◽  
Contour Lines ◽  
Digital Elevation ◽  
The Difference ◽  
Elevation Model ◽  
Topographical Relief

Open pit mining leads to irreversible changes in topographical relief, which makes a return to the original morphology virtually impossible. This is important for quarries that were part of former mining areas. This research presents an innovative approach to the reconstruction of the relief of anthropogenically transformed land on the example of Liban Quarry in Cracow, where operations began before 1873 to 1986. The basis for the reconstructed area was a Topographic Map of Poland with a scale 1:10,000 from 1997, from which a set of data was obtained to perform spatial analyses. The estimation was conducted using the ordinary kriging method, enabling a reconstruction of the morphology of the studied area and presenting it in the form of a hypsometric map and a digital elevation model. The correctness of the modelling was verified by cross-validation and a kriging standard deviation map (SDOK). These revealed low values of estimation errors in the places without contour lines on the base map. The comparison of the obtained maps and model with a Tactical Map of Poland with a scale 1:100,000 from 1934 indicated great similarities. The highest interpolation error value was recorded in the part of the pit where the difference between the actual and reconstructed elevation was about 30 m on average. In the exploited part, the SDOK did not exceed 0.52 m, and in the entire studied area, it reached a maximum of 0.56 m. The proposed approach fulfilled the assumptions of reconstruction, as the analysis revealed elements matching the historic relief in both forms of presentation of the topography of the quarry, on the obtained hypsometric map and on the tactical map. Our study is among the very few in the world concerning the application of geostatistics in the restoration of the relief of land transformed by open pit mining activities.

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