scholarly journals Perspectives on Digital Elevation Model (DEM) Simulation for Flood Modeling in the Absence of a High-Accuracy Open Access Global DEM

2018 ◽  
Vol 6 ◽  
Author(s):  
Laurence Hawker ◽  
Paul Bates ◽  
Jeffrey Neal ◽  
Jonathan Rougier
Keyword(s):  
Open Access ◽  
Digital Elevation Model ◽  
High Accuracy ◽  
Flood Modeling ◽  
Dem Simulation ◽  
Digital Elevation ◽  
Elevation Model

An Approach to Diminish Boundary Distortion in Compressing Grid DEM with Discrete Wavelet Transform

2012 ◽  
Vol 220-223 ◽  
pp. 2617-2621
Author(s):  
Zhan Qiang Chang ◽  
Xiao Meng Liu ◽  
Zu Rui Ao
Keyword(s):  
Wavelet Transform ◽  
Spatial Analysis ◽  
Data Compression ◽  
Discrete Wavelet Transform ◽  
Digital Elevation Model ◽  
High Accuracy ◽  
Discrete Wavelet ◽  
The Core ◽  
Digital Elevation ◽  
Elevation Model

Digital elevation model, the core data for 3-dimensinal visualization and spatial analysis, plays a key role in geosciences and GIS, and wavelet transform is an important tool for data compression. According to the characteristics of DEM data and wavelet transform, we proposed an approach to diminish boundary distortion in compressing grid DEM data with discrete wavelet transform, so that the compression performances are evidently improved. The experimental results indicate that not only higher compression ratios but also reconstructed DEM data with high accuracy are achieved by using the proposed approach.

scholarly journals Inundation Exposure Assessment for Majuro Atoll, Republic of the Marshall Islands Using A High-Accuracy Digital Elevation Model

2020 ◽  
Vol 12 (1) ◽  
pp. 154 ◽  
Author(s):  
Dean Gesch ◽  
Monica Palaseanu-Lovejoy ◽  
Jeffrey Danielson ◽  
Charles Fletcher ◽  
Maria Kottermair ◽  
...  
Keyword(s):  
Digital Elevation Model ◽  
High Accuracy ◽  
Probabilistic Methods ◽  
Marshall Islands ◽  
Motion Processing ◽  
Central Pacific ◽  
Digital Elevation ◽  
Elevation Data ◽  
Datum Transformation ◽  
Elevation Model

Majuro Atoll in the central Pacific has high coastal vulnerability due to low-lying islands, rising sea level, high wave events, eroding shorelines, a dense population center, and limited freshwater resources. Land elevation is the primary geophysical variable that determines exposure to inundation in coastal settings. Accordingly, coastal elevation data (with accuracy information) are critical for assessments of inundation exposure. Previous research has demonstrated the importance of using high-accuracy elevation data and rigorously accounting for uncertainty in inundation assessments. A quantitative analysis of inundation exposure was conducted for Majuro Atoll, including accounting for the cumulative vertical uncertainty from the input digital elevation model (DEM) and datum transformation. The project employed a recently produced and validated DEM derived from structure-from-motion processing of very-high-resolution aerial imagery. Areas subject to marine inundation (direct hydrologic connection to the ocean) and low-lying lands (disconnected hydrologically from the ocean) were mapped and characterized for three inundation levels using deterministic and probabilistic methods. At the highest water level modeled (3.75 ft, or 1.143 m), more than 34% of the atoll study area is likely to be exposed to inundation (68% chance or greater), while more than 20% of the atoll is extremely likely to be exposed (95% chance or greater). The study demonstrates the substantial value of a high-accuracy DEM for assessing inundation exposure of low-relief islands and the enhanced information from accounting for vertical uncertainty.

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.

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