Terrestrial and airborne laser scanning and 2-D modelling for 3-D flood hazard maps in urban areas: new opportunities and perspectives

2021 ◽  
Vol 135 ◽  
pp. 104889
Author(s):  
Pierfranco Costabile ◽  
Carmelina Costanzo ◽  
Gianluca De Lorenzo ◽  
Rosa De Santis ◽  
Nadia Penna ◽  
...  
Keyword(s):  
Urban Areas ◽  
Laser Scanning ◽  
Flood Hazard ◽  
Airborne Laser Scanning ◽  
Hazard Maps ◽  
Airborne Laser ◽  
Flood Hazard Maps

scholarly journals MULTIPLE-PRIMITIVES-BASED HIERARCHICAL CLASSIFICATION OF AIRBORNE LASER SCANNING DATA IN URBAN AREAS

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 837-843
Author(s):  
H. Ni ◽  
X. G. Lin ◽  
J. X. Zhang
Keyword(s):  
Urban Areas ◽  
Laser Scanning ◽  
Rough Surfaces ◽  
Hierarchical Classification ◽  
Airborne Laser Scanning ◽  
Smooth Surfaces ◽  
Airborne Laser ◽  
Individual Point ◽  
Point Cloud Segmentation ◽  
Third Stage

A hierarchical classification method for Airborne Laser Scanning (ALS) data of urban areas is proposed in this paper. This method is composed of three stages among which three types of primitives are utilized, i.e., smooth surface, rough surface, and individual point. In the first stage, the input ALS data is divided into smooth surfaces and rough surfaces by employing a step-wise point cloud segmentation method. In the second stage, classification based on smooth surfaces and rough surfaces is performed. Points in the smooth surfaces are first classified into ground and buildings based on semantic rules. Next, features of rough surfaces are extracted. Then, points in rough surfaces are classified into vegetation and vehicles based on the derived features and Random Forests (RF). In the third stage, point-based features are extracted for the ground points, and then, an individual point classification procedure is performed to classify the ground points into bare land, artificial ground and greenbelt. Moreover, the shortages of the existing studies are analyzed, and experiments show that the proposed method overcomes these shortages and handles more types of objects.

scholarly journals Using High-Density LiDAR Data and 2D Streamflow Hydraulic Modeling to Improve Urban Flood Hazard Maps: A HEC-RAS Multi-Scenario Approach

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1832 ◽  
Author(s):  
Alin Mihu-Pintilie ◽  
Cătălin Ioan Cîmpianu ◽  
Cristian Constantin Stoleriu ◽  
Martín Núñez Pérez ◽  
Larisa Elena Paveluc
Keyword(s):  
Urban Areas ◽  
Large Scale ◽  
Flood Hazard ◽  
Hydraulic Modeling ◽  
Flood Mitigation ◽  
Small Scale ◽  
Lidar Data ◽  
Hazard Maps ◽  
Urban Flood ◽  
Flood Hazard Maps

The ability to extract streamflow hydraulic settings using geoinformatic techniques, especially in high populated territories like urban and peri-urban areas, is an important aspect of any disaster management plan and flood mitigation effort. 1D and 2D hydraulic models, generated based on DEMs with high accuracy (e.g., Light Detection and Ranging (LiDAR)) and processed in geographic information systems (GIS) modeling software (e.g., HEC-RAS), can improve urban flood hazard maps. In this study, we present a small-scale conceptual approach using HEC-RAS multi-scenario methodology based on remote sensing (RS), LiDAR data, and 2D hydraulic modeling for the urban and peri-urban area of Bacău City (Bistriţa River, NE Romania). In order to test the flood mitigation capacity of Bacău 1 reservoir (rB1) and Bacău 2 reservoir (rB2), four 2D streamflow hydraulic scenarios (s1–s4) based on average discharge and calculated discharge (s1–s4) data for rB1 spillway gate (Sw1) and for its hydro-power plant (H-pp) were computed. Compared with the large-scale flood hazard data provided by regional authorities, the 2D HEC-RAS multi-scenario provided a more realistic perspective about the possible flood threats in the study area and has shown to be a valuable asset in the improvement process of the official flood hazard maps.

scholarly journals Improving Urban Flood Mapping by Merging Synthetic Aperture Radar-Derived Flood Footprints with Flood Hazard Maps

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1577
Author(s):  
David C. Mason ◽  
John Bevington ◽  
Sarah L. Dance ◽  
Beatriz Revilla-Romero ◽  
Richard Smith ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Real Time ◽  
Rural Areas ◽  
Urban Areas ◽  
Flood Hazard ◽  
Synthetic Aperture ◽  
Hazard Maps ◽  
Urban Flood ◽  
Flood Hazard Maps ◽  
Aperture Radar

Remotely sensed flood extents obtained in near real-time can be used for emergency flood incident management and as observations for assimilation into flood forecasting models. High-resolution synthetic aperture radar (SAR) sensors have the potential to detect flood extents in urban areas through clouds during both day- and night-time. This paper considers a method for detecting flooding in urban areas by merging near real-time SAR flood extents with model-derived flood hazard maps. This allows a two-way symbiosis, whereby currently available SAR urban flood extent improves future model flood predictions, while flood hazard maps obtained after the SAR overpasses improve the SAR estimate of urban flood extents. The method estimates urban flooding using SAR backscatter only in rural areas adjacent to urban ones. It was compared to an existing method using SAR returns in both rural and urban areas. The method using SAR solely in rural areas gave an average flood detection accuracy of 94% and a false positive rate of 9% in the urban areas and was more accurate than the existing method.

scholarly journals QUALITY EVALUATION OF 3D BUILDING MODELS BASED ON LOW-ALTITUDE IMAGERY AND AIRBORNE LASER SCANNING POINT CLOUDS

2021 ◽  
Vol XLIII-B2-2021 ◽  
pp. 345-352
Author(s):  
G. Gabara ◽  
P. Sawicki
Keyword(s):  
Urban Areas ◽  
Point Cloud ◽  
Laser Scanning ◽  
Wide Spectrum ◽  
Vertical Plane ◽  
Point Clouds ◽  
Airborne Laser Scanning ◽  
Airborne Laser ◽  
Building Models ◽  
Low Altitude

Abstract. The term “3D building models” is used in relation to the CityGML models and building information modelling. Reconstruction and modelling of 3D building objects in urban areas becomes a common trend and finds a wide spectrum of utilitarian applications. The paper presents the quality assessment of two multifaceted 3D building models, which were obtained from two open-access databases: Polish national Geoportal (accuracy in LOD 2 standard) and Trimble SketchUp Warehouse (accuracy in LOD 2 standard with information about architectural details of façades). The Geoportal 3D models were primary created based on the airborne laser scanning data (density 12 pts/sq. m, elevation accuracy to 0.10 m) collected during Informatic System for Country Protection against extraordinary hazards project. The testing was performed using different validation low-altitude photogrammetric datasets: RIEGL LMS-Q680i airborne laser scanning point cloud (min. density 25 pts/sq. m and height accuracy 0.03 m), and image-based Phase One iXU-RS 1000 point cloud (average accuracy in the horizontal and in the vertical plane is respectively to 0.015 m and 0.030 m). The visual comparison, heat maps with the function of the signed distance, and histograms in predefined ranges were used to evaluate the quality and accuracy of 3D building models. The aspect of error sources that occurred during the modelling process was also discussed.

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