scholarly journals Reconstructing Pre-Industrial Long Distance Roads in a Hilly Region in Germany, Based on Historical and Archaeological Data

2017 ◽  
Vol 1 (2) ◽  
pp. 642-660 ◽  
Author(s):  
Irmela Herzog
Keyword(s):  
Cross Sections ◽  
Lidar Data ◽  
Long Distance ◽  
Early 19Th Century ◽  
Digital Elevation ◽  
Hilly Region ◽  
Local Accuracy ◽  
Cost Paths ◽  
Elevation Model ◽  
The One

The aim of this contribution is on the one hand to map pre-industrial long distance roads located in a hilly region east of Cologne, Germany, as exactly as possible and on the other hand to assess the accuracy of least-cost approaches that are increasingly applied by archaeologists for prehistoric road reconstruction. Probably the earliest map covering the study area east of Cologne dates back to 1575. The map is distorted so that rectification is difficult. But it is possible to assess the local accuracy of the map and to transfer the approximate routes to a modern map manually. Most of the area covered by the 1575 map is also depicted on a set of more accurate maps created in the early 19th century and a somewhat later historical map set (ca. 1842 AD). The historical roads on these rectified historical maps close to the approximate roads were digitized and compared to the outcomes of least-cost analysis, specifically least-cost paths and accessibility maps. Based on these route reconstructions with limited accuracy, Lidar data is checked to identify remains of these roads. Several approaches for visualizing Lidar data are tested to identify appropriate methods for detecting sunken roads. Possible sunken roads detected on the Lidar images were validated by checking cross sections in the digital elevation model and in the field.

scholarly journals MAT: GIS-Based Morphometry Assessment Tools for Concave Landforms

2021 ◽  
Vol 13 (14) ◽  
pp. 2810
Author(s):  
Joanna Gudowicz ◽  
Renata Paluszkiewicz
Keyword(s):  
Rapid Development ◽  
Assessment Tools ◽  
Lidar Data ◽  
Automatic Extraction ◽  
Sensing Technology ◽  
Digital Elevation ◽  
Elevation Data ◽  
Elevation Model ◽  
Morphometric Assessment ◽  
Morphometric Evaluation

The rapid development of remote sensing technology for obtaining high-resolution digital elevation models (DEMs) in recent years has made them more and more widely available and has allowed them to be used for morphometric assessment of concave landforms, such as valleys, gullies, glacial cirques, sinkholes, craters, and others. The aim of this study was to develop a geographic information systems (GIS) toolbox for the automatic extraction of 26 morphometric characteristics, which include the geometry, hypsometry, and volume of concave landforms. The Morphometry Assessment Tools (MAT) toolbox in the ArcGIS software was developed. The required input data are a digital elevation model and the form boundary as a vector layer. The method was successfully tested on an example of 21 erosion-denudation valleys located in the young glacial area of northwest Poland. Calculations were based on elevation data collected in the field and LiDAR data. The results obtained with the tool showed differences in the assessment of the volume parameter at the average level of 12%, when comparing the field data and LiDAR data. The algorithm can also be applied to other types of concave forms, as well as being based on other DEM data sources, which makes it a universal tool for morphometric evaluation.

scholarly journals CREATING DIGITAL ELEVATION MODEL USING A MOBILE DEVICE

2017 ◽  
Vol IV-4/W4 ◽  
pp. 203-207 ◽  
Author(s):  
A. İ. Durmaz
Keyword(s):  
Mobile Devices ◽  
Digital Elevation Model ◽  
Mobile Device ◽  
Point Clouds ◽  
Lidar Data ◽  
Government Agencies ◽  
Gps Data ◽  
Digital Elevation ◽  
The World ◽  
Elevation Model

DEM (Digital Elevation Models) is the best way to interpret topography on the ground. In recent years, lidar technology allows to create more accurate elevation models. However, the problem is this technology is not common all over the world. Also if Lidar data are not provided by government agencies freely, people have to pay lots of money to reach these point clouds. In this article, we will discuss how we can create digital elevation model from less accurate mobile devices’ GPS data. Moreover, we will evaluate these data on the same mobile device which we collected data to reduce cost of this modeling.

scholarly journals An Improved Ball Pivot Algorithm-Based Ground Filtering Mechanism for LiDAR Data

2019 ◽  
Vol 11 (10) ◽  
pp. 1179 ◽  
Author(s):  
Wei Ma ◽  
Qingquan Li
Keyword(s):  
Spatial Relationship ◽  
Single Layer ◽  
Experimental Results ◽  
Lidar Data ◽  
Initial Surface ◽  
Seed Point ◽  
Pivot Algorithm ◽  
Group Iii ◽  
Digital Elevation ◽  
Elevation Model

Automatic ground filtering is an essential step for Digital Elevation Model (DEM) generation, which has significant application value. However, extraction and classification of ground points from the Light Detection and Ranging (LiDAR) data, especially in multitudinous terrain situations, is a challenging task because it is difficult to determine the set of optimal parameters for removing various non-ground features. In this paper, a new ground filtering technique based on an improved Ball Pivot Algorithm (BPA) is proposed. At the beginning, the LiDAR point cloud dataset was divided into different subsets based on the 2D regular grid. The lowest point in each grid was selected as the seed point to build a single-layer surface. After that, the improved BPA was executed to remove points on the higher location. Then, the rest of the points were calculated and selected as a new seed point according to the spatial relationship with the initial surface. Finally, non-ground points were filtered by means of improved BPA traversing all the grids. Our experimental results on the Benchmark dataset provided by the International Society for Photogrammetry and Remote Sensing (ISPRS) Working Group III/3 showed high accuracy (with a mean kappa coefficient over 80%) in terms of completeness, correctness, and quality for DEM generation. The experimental results demonstrated the proposed method is robust to various terrain situations, as it is more effective and feasible for ground filtering.

scholarly journals Revision of the geological map and 3D modelling of the geological structure of the Samaria Gorge Region, W. Crete

2001 ◽  
Vol 34 (1) ◽  
pp. 29 ◽  
Author(s):  
Ε. ΜΑΝΟΥΤΣΟΓΛΟΥ ◽  
Ε. ΣΠΥΡΙΔΩΝΟΣ ◽  
Α. SOUJON ◽  
V. JACOBSHAGEN
Keyword(s):  
Geometric Model ◽  
Short Review ◽  
Geological Structure ◽  
Geological Mapping ◽  
3D Cad ◽  
Digital Elevation ◽  
Geological Map ◽  
Interactive 3D ◽  
Elevation Model ◽  
The One

The island of Crete is situated near the front of an active plate margin. Therefore, it is of great interest in the framework of the International Continental Drilling Project (I.C.D.P.). A short review of the digital modelling methods, their applications in the geosciences and the associated advantages is also presented. The digital 3-dimensional geometric model of the geological structure of the Samaria Gorge region is based on the study of the stratigraphy and the tectonic evolution of the metamorphic rocks of the Plattenkalk group in SW Crete. Data from the geological map of Greece (Vatolakkos sheet, 1:50.000) and from the literature have been supplemented by geological mapping and structural analyses. In our study we applied interactive 3D CAD methods implemented in the integrated software package SURPAC2000. The surface geology has been draped over a digital elevation model of the topography in order to model the geometry of the subsurface structures. Two hypotheses about the geological structure of the region are examined: a) the one given by the existing geological map, which proposes a syncline structure and b) the one resulting from the combination of existing data, corrections carried out through repeated 3D simulations and new field observations. After distinguishing in the S of the study area the Trypali union, overthrusted on the Plattenkalk group, we propose an anticline structure with a NNE/SSW striking axis dipping to the NE.

scholarly journals Floods Risk Mapping and Assessing Vulnerability of Morang, Nepal

2021 ◽  
Author(s):  
Pawan Thapa ◽  
Narayan Thapa
Keyword(s):  
Drainage Density ◽  
Google Earth ◽  
Food And Agriculture ◽  
Food And Agriculture Organization ◽  
Digital Elevation ◽  
Two Factors ◽  
Flooding Risk ◽  
Elevation Model ◽  
The One ◽  
The Impact

Abstract Background: The impact of flooding rises due to unplanned settlements, especially in developing and underdeveloped countries. This study tries to address these issues by mapping flood risk places and assessing their impact on population and household.Methods: This study used the dataset available in Google Earth Engine (GEE), Food and Agriculture Organization (FAO), Central Bureau Statistics (CBS), Earth Data for preparing slope, drainage density, digital elevation model, rainfall, land use map, and soil map. These maps create using GEE and QGIS through overlay analysis that has two factors. The one is influence and other slopes, and it has provided high and low value according to its role on flooding.Results: The risk assessment shows around twenty-four percent population is at higher risk, whereas more than three thousand settlements are prone to flooding. It depicts a significant increasing trend of floods in the Morang district.Conclusion: This settlement risk map can help determine the flood safe and very high-risk areas in the Morang district. It will support residential places' planning by the local government, urban planners, and community people to reduce flooding risk.

scholarly journals Managing the Flood Waves from Hemrin Dam

2021 ◽  
Vol 27 (7) ◽  
pp. 42-52
Author(s):  
Hajir Majid Ghali ◽  
Riyadh Z. Azzubaidi
Keyword(s):  
Cross Sections ◽  
Design Flood ◽  
Digital Elevation ◽  
Full Capacity ◽  
High Flood ◽  
Diyala River ◽  
Elevation Model ◽  
Strategic Study ◽  
Drop Structure ◽  
Flood Waves

Diyala Governorate was exposed recently to high flood waves discharged from Hemrin Dam to Diyala River when the dam reached its full capacity. The recently recorded discharge capacity of Diyala River was reduced to just 750m3/s. This exposes cities and villages along the Diyala River to flood risk when discharging the flood waves, which may reach 3000 m3/s. It is important to manage, suggest, and design flood escapes to discharge the flood waves from Hemrin Dam away from Diyala River. This escape branches from Hemrin Lake towards Ashweicha Marsh. One dimensional hydraulic model was developed to simulate the flow within the escape by using HEC-RAS software. Eighty-two cross-sections were extracted from the digital elevation model for the escape and used as geometric data. Moreover, thirty cross-sections for the Diyala River were utilized from the Strategic Study for Water and Land Resources in Iraq. Since the escape passes through two regions of different geological formations, two roughness coefficients of 0.035and0.028were used. Two discharge cases were applied3000m3/s, which is the 500 years return period extreme hydrograph of Hemrin Dam, and 4000 m3/s, which is the design discharge of Hemrin Dam spillway. A spillway was proposed at the escape entrance with crest level 105m.a.m.s.l., followed by a drop structure with eighteen rectangular steps

scholarly journals Influence of different sources of topographic data on flood mapping: urban area São Vendelino municipality, southern Brazil

RBRH ◽  
2020 ◽  
Vol 25 ◽  
Author(s):  
Fernando Campo Zambrano ◽  
Masato Kobiyama ◽  
Marco Alésio Figueiredo Pereira ◽  
Gean Paulo Michel ◽  
Fernando Mainardi Fan
Keyword(s):  
Cross Sections ◽  
Field Survey ◽  
Flood Mapping ◽  
Mean Velocity ◽  
Topographic Data ◽  
Digital Elevation ◽  
Wetted Area ◽  
Elevation Model ◽  
Best Fit ◽  
Different Sources

ABSTRACT Generally, the base for any flood mapping is the topography information whose resolution determines the map accuracy. Furthermore, river bathymetry in detail and the type of used model are also relevant. Therefore, the objective of the present study was to evaluate the influence of different sources of topographic data on the flood mapping by using the CAESAR-Lisflood model and three Digital Elevation Model (DEM) configurations, among which two were freely available, and the other was generated with field survey (topography and bathymetry). First, the resolution and precision of each DEM were evaluated, from the comparison of different cross-sections, besides the variation of the wetted area and absolute value of the relative error in mean velocity as a function of depth. Subsequently, after elaborating flood maps with each DEM, the results were compared in terms of flood area, mean flood width and flow depth. It is observed that the more accurate resolution, the smaller the flood area becomes. The flood map elaborated with the DEM through field survey had the best fit to the observed area. However the relation between the topographic resolutions and flow-depths was not clear in obtained results.

scholarly journals Technical Note: Water flow routing on irregular meshes

2006 ◽  
Vol 3 (6) ◽  
pp. 3675-3689 ◽  
Author(s):  
D. Bänninger
Keyword(s):  
Water Flow ◽  
Cross Section ◽  
Cross Sections ◽  
Technical Note ◽  
Hill Slope ◽  
Digital Elevation ◽  
Irregular Meshes ◽  
Elevation Model ◽  
Local Gradient ◽  
Flow Cross

Abstract. For spatial explicit hydrological modelling an algorithm was needed which works as cellular automata on irregular meshes. From literature it was found that usual algorithms applied for this purpose do not route the water flow correctly to its adjacent cells. In this study the hydraulic linking between mesh cells is done by calculating the flow cross section between the mesh cells. The flow cross sections are positioned in the centre of the mesh edges and are perpendicular to the local gradient of the digital elevation model. The presented algorithm is simple in its implementation and efficient in computation. It is shown that the proposed algorithm works correctly for different synthesised hill slope shapes.

scholarly journals Floods Risk Mapping and Assessing Vulnerability of Morang, Nepal

2021 ◽  
Author(s):  
Pawan Thapa ◽  
Narayan Thapa
Keyword(s):  
Drainage Density ◽  
Google Earth ◽  
Food And Agriculture ◽  
Food And Agriculture Organization ◽  
Digital Elevation ◽  
Two Factors ◽  
Flooding Risk ◽  
Elevation Model ◽  
The One ◽  
The Impact

Abstract Background: The impact of flooding rises due to unplanned settlements, especially in developing countries. This study tries to address these issues by mapping flood risk places and assessing their impact on population and household.Methods: This study used the dataset available in Google Earth Engine (GEE), Food and Agriculture Organization (FAO), Central Bureau Statistics (CBS), Earth Data for preparing slope, drainage density, digital elevation model, rainfall, land use map, and soil map. These maps create using GEE and QGIS through overlay analysis that has two factors. The one is influence and other slopes, and it has provided high and low value according to its role on flooding.Results: The risk assessment shows around twenty-four percent population is at higher risk, whereas more than three thousand settlements are prone to flooding. It depicts a significant increasing trend of floods in the Morang district.Conclusion: This settlement risk map can help determine the flood safe and very high-risk areas in the Morang district. It will support residential places' planning by the local government, urban planners, and community people to reduce flooding risk.

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