Apport de la technique du krigeage avec dérive externe pour une cartographie raisonnée de l'équivalent en eau de la neige : Application aux bassins de la rivière Gatineau

2005 ◽  
Vol 32 (1) ◽  
pp. 289-297 ◽  
Author(s):  
Dominique Tapsoba ◽  
Vincent Fortin ◽  
François Anctil ◽  
Mario Haché
Keyword(s):  
Root Mean Square ◽  
Digital Elevation Model ◽  
Snow Water Equivalent ◽  
Mean Square ◽  
Kriging With External Drift ◽  
Digital Elevation ◽  
Snow Water ◽  
Elevation Model ◽  
Mean Square Errors ◽  
External Drift

The geostatistical algorithm of kriging with external drift (KED) is applied to the spatial estimation of snow water equivalent measured at single points. A digital elevation model with a 10-km resolution is used as external drift. Over the dense network of the period of interest (mid-March 1982), which corresponds to the maximum snow accumulation and the beginning of the snow melt in the Gatineau River basin, the KED technique is compared to the univariate ordinary kriging (OK). The results indicate a significant estimation precision improvement when the KED technique is used, notably in the under-sampled and extrapolated zones. A quantitative performance barometer — the root-mean-square (RMS) error — of this method with regards to the various degradation levels of the snow depth measurement network is proposed.Key words: snow water equivalent, kriging with external drift, root-mean-square errors, digital elevation model.[Journal translation]

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

2019 ◽  
Vol 28 (1) ◽  
pp. 95-105 ◽  
Author(s):  
I. P. Kovalchuk ◽  
K. A. Lukianchuk ◽  
V. A. Bogdanets
Keyword(s):  
Open Source ◽  
Correlation Coefficient ◽  
Root Mean Square ◽  
Digital Elevation Models ◽  
Mean Square ◽  
Erosion Processes ◽  
Aster Gdem ◽  
Digital Elevation ◽  
Vertical Accuracy ◽  
Mean Square Errors

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.

Using the Digital Elevation Model (DEM) to Improve the Spatial Coverage of the MODIS Based Reservoir Monitoring Network in South Asia

2020 ◽  
Vol 12 (5) ◽  
pp. 745 ◽  
Author(s):  
Shuai Zhang ◽  
Huilin Gao
Keyword(s):  
South Asia ◽  
Digital Elevation Model ◽  
Hydrological Modeling ◽  
High Density ◽  
Regulated River ◽  
Reservoir Storage ◽  
Digital Elevation ◽  
Spatial Coverage ◽  
Elevation Model ◽  
Mean Square Errors

Satellite remote sensing of near real-time reservoir storage variations has important implications for flood monitoring and water resources management. However, satellite altimetry data, which are essential for estimating storage variations, are only available for a limited number of reservoirs. This lack of high-density spatial coverage directly hinders the potential use of remotely sensed reservoir information for improving the skills of hydrological modeling over highly regulated river basins. To solve this problem, a reservoir storage dataset with high-density spatial coverage was developed by combining the water surface area estimated from Moderate Resolution Imaging Spectroradiometer (MODIS) imageries with the Digital Elevation Model (DEM) data collected by the Shuttle Radar Topography Mission (SRTM). By including more reservoirs, this reservoir dataset represents 46.6% of the overall storage capacity in South Asia. The results were validated over five reservoirs where gauge observations are accessible. The storage estimates agree well with observations, with coefficients of determination ranging from 0.47 to 0.91 and normalized root mean square errors (NRMSE) ranging from 15.46% to 37.69%. Given the general availability of MODIS and SRTM data, this algorithm can be potentially applied for monitoring global reservoirs at a high density.

scholarly journals Analisis Penambahan Resolusi Digital Elevation Model (DEM) dengan Menggunakan Metode Interpolasi Inverse Distance Weighted (IDW) untuk Aplikasi Analisis Potensi Longsoran

2019 ◽  
Author(s):  
Rustan
Keyword(s):  
Root Mean Square Error ◽  
Digital Elevation Model ◽  
Mean Square ◽  
Data Input ◽  
Data Format ◽  
Inverse Distance Weighted ◽  
Digital Elevation ◽  
Distance Weighted ◽  
Elevation Model ◽  
Inverse Distance

Informasi ketinggian suatu tempat di permukaan bumi (elevasi) merupakan hal yang sangat penting di dalamanalisis geospasial. Data elevasi tersebut umumnya disimpan dalam bentuk Digital Elevation Model (DEM).DEM selanjutnya diintegrasikan dengan data geospasial lainnya di dalam GIS untuk berbagai keperluan.Lembaga formal seperti USGS, NASA, METI secara aktif melakukan pengambilan data DEM melaluiteknologi satelit dan menyediakan data DEM secara global dan dapat diperoleh secara online. Namundemikian, umumnya DEM yang tersedia secara gratis adalah DEM dengan ketelitian piksel 30 m atau lebihbesar. Khusus untuk wilayah Indonesia, ketersediaan data DEM dengan resolusi yang lebih tinggi masihsangat minimal. Padahal data DEM resolusi tinggi dibutuhkan untuk berbagai macam aplikasi misalnyasebagai data input dalam pemodelan debris flow. Pembuatan DEM dengan resolusi yang lebih tinggi dapatdilakukan melalui interpolasi titik ketinggian. Data digital berupa ketinggian yang didapat dari DEM SRTM30 m dalam bentuk format raster diekstrak di ArcMap kemudian diubah menjadi data format point sebagaiinput untuk proses interpolasi. Pada penelitian ini, akan dilakukan pembuatan DEM resolusi 5 mmenggunakan metode interpolasi Inverse Distance Weighted (IDW). Penelitian ini dilakukan pada daerahyang rawan longsor di Jawa Barat. Akurasi hasil interpolasi dilakukan dengan membandingan DEMsebelum interpolasi baik secara kualitatif dan kuantitatif. Tingkat akurasi hasil interpolasi data DEM secarakuantitatif dinyatakan dalam RMSE (Root Mean Square Error).

STUDY OF THE LANDSLIDE MORPHOLOGY BASED ON GNSS DATA AND AIRBORNE SOUNDING (ON THE EXAMPLE OF A SECTION OF THE PROTVA RIVER VALLEY)

2018 ◽  
Vol 12 (5-6) ◽  
pp. 50-57 ◽  
Author(s):  
I. S. Voskresensky ◽  
A. A. Suchilin ◽  
L. A. Ushakova ◽  
V. M. Shaforostov ◽  
A. L. Entin ◽  
...  
Keyword(s):  
Digital Elevation Model ◽  
Geodetic Network ◽  
Aerial Survey ◽  
River Valley ◽  
Ease Of Use ◽  
Digital Elevation ◽  
Loose Deposits ◽  
Positioning Method ◽  
Landslide Body ◽  
Elevation Model

To use unmanned aerial vehicles (UAVs) for obtaining digital elevation models (DEM) and digital terrain models (DTM) is currently actively practiced in scientific and practical purposes. This technology has many advantages: efficiency, ease of use, and the possibility of application on relatively small area. This allows us to perform qualitative and quantitative studies of the progress of dangerous relief-forming processes and to assess their consequences quickly. In this paper, we describe the process of obtaining a digital elevation model (DEM) of the relief of the slope located on the bank of the Protva River (Satino training site of the Faculty of Geography, Lomonosov Moscow State University). To obtain the digital elevation model, we created a temporary geodetic network. The coordinates of the points were measured by the satellite positioning method using a highprecision mobile complex. The aerial survey was carried out using an unmanned aerial vehicle from a low altitude (about 40–45 m). The processing of survey materials was performed via automatic photogrammetry (Structure-from-Motion method), and the digital elevation model of the landslide surface on the Protva River valley section was created. Remote sensing was supplemented by studying archival materials of aerial photography, as well as field survey conducted immediately after the landslide. The total amount of research results made it possible to establish the causes and character of the landslide process on the study site. According to the geomorphological conditions of formation, the landslide refers to a variety of landslideslides, which are formed when water is saturated with loose deposits. The landslide body was formed with the "collapse" of the blocks of turf and deluvial loams and their "destruction" as they shifted and accumulated at the foot of the slope.

Sign in / Sign up

Export Citation Format

Share Document