scholarly journals Zero Watermarking for the TIN DEM Data Based on the Edge Length

2021 ◽  
Vol 10 (8) ◽  
pp. 559
Author(s):  
Qifei Zhou ◽  
Changqing Zhu ◽  
Na Ren
Keyword(s):  
Edge Length ◽  
Majority Voting ◽  
Data Simulation ◽  
Triangulated Irregular Network ◽  
Digital Elevation ◽  
Crucial Problem ◽  
Simulation Results ◽  
Elevation Model ◽  
Zero Watermarking ◽  
Voting Mechanism

How to keep the fidelity of the digital elevation model (DEM) data is a crucial problem in the current watermarking research, as the watermarked DEM data need to preserve their accuracy. We proposed a zero watermarking method for the triangulated irregular network (TIN) DEM data. It takes full advantage of the characteristics of the edge length in the TIN DEM data. First, the radio of the edge lengths is quantified to the watermark index, and then the comparison of the edge lengths is quantified to the watermark bit. Finally, the watermark is constructed by combing the watermark bits according to the watermark indices with the help of the majority voting mechanism. In the method, the TIN DEM data are only used to construct the watermark, not to be embedded by the watermark. Therefore, the data quality is preserved to the greatest extent. Experiments verify the theoretical achievements of this method and demonstrate the method is lossless to the TIN DEM data. Simulation results also show that the method has good robustness on translation, rotation, scaling, and cropping attacks.

scholarly journals Hydrologic analysis of a flood based on a new Digital Elevation Model

2015 ◽  
Vol XL-7/W4 ◽  
pp. 127-134 ◽  
Author(s):  
M. Nishio ◽  
M. Mori
Keyword(s):  
Digital Elevation Model ◽  
Spatial Resolution ◽  
Meteorological Data ◽  
Data Acquisition System ◽  
Hydrologic Processes ◽  
Hydrologic Analysis ◽  
Digital Elevation ◽  
Simulation Results ◽  
Typhoon Season ◽  
Elevation Model

These The present study aims to simulate the hydrologic processes of a flood, based on a new, highly accurate Digital Elevation Model (DEM). The DEM is provided by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) of Japan, and has a spatial resolution of five meters. It was generated by the new National Project in 2012. The Hydrologic Engineering Center - Hydrologic Modeling System (HEC-HMS) is used to simulate the hydrologic process of a flood of the Onga River in Iizuka City, Japan. A large flood event in the typhoon season in 2003 caused serious damage around the Iizuka City area. Precise records of rainfall data from the Automated Meteorological Data Acquisition System (AMeDAS) were input into the HEC-HMS. The estimated flood area of the simulation results by HEC-HMS was identical to the observed flood area. A watershed aggregation map is also generated by HEC-HMS around the Onga River.

Visibility Analysis of GNSS Satellites in Mountainous Area

2012 ◽  
Vol 588-589 ◽  
pp. 888-892
Author(s):  
Bo Zhang ◽  
Jing Zhao ◽  
Wen Wei Duan ◽  
Long Yang Yu
Keyword(s):  
Digital Elevation Model ◽  
The Other ◽  
Visible Range ◽  
Mountainous Area ◽  
Visibility Analysis ◽  
Other Hand ◽  
Digital Elevation ◽  
Novel Method ◽  
Simulation Results ◽  
Elevation Model

A novel method of analyzing the visibility of GNSS satellites in mountainous area is proposed by taking advantage of target area’s digital elevation model (DEM) data and GNSS almanac. The key point is calculating the obstacle elevation on the basis of target points’ visible range. Simulation results show that both different target points at the same time and same point at different time have different situation of visible satellites on the condition with or without obstacle. On the other hand, this method contributes lots to determine the distribution of pseudolites in mountainous area.

scholarly journals Impact of DEM Resolution and Spatial Scale: Analysis of Influence Factors and Parameters on Physically Based Distributed Model

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Hanchen Zhang ◽  
Zhijia Li ◽  
Muhammad Saifullah ◽  
Qiaoling Li ◽  
Xiao Li
Keyword(s):  
Influence Factors ◽  
Distributed Model ◽  
Small Scale ◽  
Simulation Accuracy ◽  
Digital Elevation ◽  
Physically Based ◽  
Simulation Results ◽  
Distributed Hydrological Models ◽  
Elevation Model ◽  
Sensitive Parameters

Physically based distributed hydrological models were used to describe small-scale hydrological information in detail. However, the sensitivity of the model to spatially varied parameters and inputs limits the accuracy for application. In this paper, relevant influence factors and sensitive parameters were analyzed to solve this problem. First, a set of digital elevation model (DEM) resolutions and channel thresholds were generated to extract the hydrological influence factors. Second, a numerical relationship between sensitive parameters and influence factors was established to define parameters reasonably. Next, the topographic index (TI) was computed to study the similarity. At last, simulation results were analyzed in two different ways: (1) to observe the change regularity of influence factors and sensitive parameters through the variation of DEM resolutions and channel thresholds and (2) to compare the simulation accuracy of the nested catchment, particularly in the subcatchments and interior grids. Increasing the grid size from 250 m to 1000 m, the TI increased from 9.08 to 11.16 and the Nash-Sutcliffe efficiency (NSE) decreased from 0.77 to 0.75. Utilizing the parameters calculated by the established relationship, the simulation results show the same NSE in the outlet and a better NSE in the simple subcatchment than the calculated interior grids.

scholarly journals Simulation Of Flood Mapping in Amasing Kali Village Using HEC-RAS 2D

2021 ◽  
Vol 328 ◽  
pp. 10003
Author(s):  
Ichsan Rauf ◽  
Imran ◽  
Idhar Sahdar
Keyword(s):  
Digital Elevation Model ◽  
Return Periods ◽  
Model Data ◽  
Gis Application ◽  
The North ◽  
Digital Elevation ◽  
Simulation Results ◽  
Elevation Model ◽  
Digital Elevation Model Data ◽  
North And South

This study aims to map the distribution of floods that occurred due to the overflow of the Amasing Kali River on Bacan Island, South Halmahera. The magnitude of the flood as an input in the Watershed (DAS) system was analyzed using the Nakayasu unit synthetic hydrograph (HSS) method, while the morphometric characteristics of the watershed were analyzed by extracting digital elevation model data (Digital Elevation Model, DEM) using a Geographic Information System (GIS) application. The simulation of flood distribution with return periods of 2, 5, 10 and 25 years was carried out by applying the HecRAS 2D application. The mapping of the analysis and simulation results of this study shows that the potential flood-affected areas are on the north and south sides of Amasing Kali village with inundation heights varying between 0.50 m – 1.50 m.

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.

Urban Flood Mapping

2017 ◽  
Author(s):  
Indra Riyanto ◽  
Lestari Margatama
Keyword(s):  
Natural Disasters ◽  
Satisfying Condition ◽  
Three Dimensions ◽  
Urban Flood ◽  
Digital Elevation ◽  
Elevation Data ◽  
Recent Occurrence ◽  
Elevation Model ◽  
Digital Elevation Model Data ◽  
Potential Area

The recent degradation of environment quality becomes the prime cause of the recent occurrence of natural disasters. It also contributes in the increase of the area that is prone to natural disasters. Flood history data in Jakarta shows that flood occurred mainly during rainy season around January – February each year, but the flood area varies each year. This research is intended to map the flood potential area in DKI Jakarta by segmenting the Digital Elevation Model data. The data used in this research is contour data obtained from DPP–DKI with the resolution of 1 m. The data processing involved in this research is extracting the surface elevation data from the DEM, overlaying the river map of Jakarta with the elevation data. Subsequently, the data is then segmented using watershed segmentation method. The concept of watersheds is based on visualizing an image in three dimensions: two spatial coordinates versus gray levels, in which there are two specific points; that are points belonging to a regional minimum and points at which a drop of water, if placed at the location of any of those points, would fall with certainty to a single minimum. For a particular regional minimum, the set of points satisfying the latter condition is called the catchments basin or watershed of that minimum, while the points satisfying condition form more than one minima are termed divide lines or watershed lines. The objective of this segmentation is to find the watershed lines of the DEM image. The expected result of the research is the flood potential area information, especially along the Ciliwung river in DKI Jakarta.

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