scholarly journals Fusion of Multi-Sensor-Derived Heights and OSM-Derived Building Footprints for Urban 3D Reconstruction

2019 ◽  
Vol 8 (4) ◽  
pp. 193 ◽  
Author(s):  
Hossein Bagheri ◽  
Michael Schmitt ◽  
Xiaoxiang Zhu
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Point Clouds ◽  
Original Data ◽  
Markup Language ◽  
Geography Markup Language ◽  
Building Models ◽  
Extensive Coverage ◽  
Constant Height ◽  
Digital Elevation

So-called prismatic 3D building models, following the level-of-detail (LOD) 1 of the OGC City Geography Markup Language (CityGML) standard, are usually generated automatically by combining building footprints with height values. Typically, high-resolution digital elevation models (DEMs) or dense LiDAR point clouds are used to generate these building models. However, high-resolution LiDAR data are usually not available with extensive coverage, whereas globally available DEM data are often not detailed and accurate enough to provide sufficient input to the modeling of individual buildings. Therefore, this paper investigates the possibility of generating LOD1 building models from both volunteered geographic information (VGI) in the form of OpenStreetMap data and remote sensing-derived geodata improved by multi-sensor and multi-modal DEM fusion techniques or produced by synthetic aperture radar (SAR)-optical stereogrammetry. The results of this study show several things: First, it can be seen that the height information resulting from data fusion is of higher quality than the original data sources. Secondly, the study confirms that simple, prismatic building models can be reconstructed by combining OpenStreetMap building footprints and easily accessible, remote sensing-derived geodata, indicating the potential of application on extensive areas. The building models were created under the assumption of flat terrain at a constant height, which is valid in the selected study area.

scholarly journals Seismic Damage Semantics on Post-Earthquake LOD3 Building Models Generated by UAS

2021 ◽  
Vol 10 (5) ◽  
pp. 345
Author(s):  
Konstantinos Chaidas ◽  
George Tataris ◽  
Nikolaos Soulakellis
Keyword(s):  
Point Clouds ◽  
Recovery Phase ◽  
Seismic Damage ◽  
Unmanned Aircraft ◽  
Earthquake Scenario ◽  
Geography Markup Language ◽  
3D Point Clouds ◽  
Building Models ◽  
Building Walls ◽  
Oblique Images

In a post-earthquake scenario, the semantic enrichment of 3D building models with seismic damage is crucial from the perspective of disaster management. This paper aims to present the methodology and the results for the Level of Detail 3 (LOD3) building modelling (after an earthquake) with the enrichment of the semantics of the seismic damage based on the European Macroseismic Scale (EMS-98). The study area is the Vrisa traditional settlement on the island of Lesvos, Greece, which was affected by a devastating earthquake of Mw = 6.3 on 12 June 2017. The applied methodology consists of the following steps: (a) unmanned aircraft systems (UAS) nadir and oblique images are acquired and photogrammetrically processed for 3D point cloud generation, (b) 3D building models are created based on 3D point clouds and (c) 3D building models are transformed into a LOD3 City Geography Markup Language (CityGML) standard with enriched semantics of the related seismic damage of every part of the building (walls, roof, etc.). The results show that in following this methodology, CityGML LOD3 models can be generated and enriched with buildings’ seismic damage. These models can assist in the decision-making process during the recovery phase of a settlement as well as be the basis for its monitoring over time. Finally, these models can contribute to the estimation of the reconstruction cost of the buildings.

scholarly journals A Semantics-Based Approach for Simplifying IFC Building Models to Facilitate the Use of BIM Models in GIS

2021 ◽  
Vol 13 (22) ◽  
pp. 4727
Author(s):  
Junxiang Zhu ◽  
Peng Wu ◽  
Chimay Anumba
Keyword(s):  
Information Modeling ◽  
Markup Language ◽  
Model Simplification ◽  
Geography Markup Language ◽  
Building Models ◽  
Solid Models ◽  
External Objects ◽  
Surface Models ◽  
Level Of Details ◽  
Building Information

Using solid building models, instead of the surface models in City Geography Markup Language (CityGML), can facilitate data integration between Building Information Modeling (BIM) and Geographic Information System (GIS). The use of solid models, however, introduces a problem of model simplification on the GIS side. The aim of this study is to solve this problem by developing a framework for generating simplified solid building models from BIM. In this framework, a set of Level of Details (LoDs) were first defined to suit solid building models—referred to as s-LoD, ranging from s-LoD1 to s-LoD4—and three unique problems in implementing s-LoDs were identified and solved by using a semantics-based approach, including identifying external objects for s-LoD2 and s-LoD3, distinguishing various slabs, and generating valid external walls for s-LoD2 and s-LoD3. The feasibility of the framework was validated by using BIM models, and the result shows that using semantics from BIM can make it easier to convert and simplify building models, which in turn makes BIM information more practical in GIS.

scholarly journals Fusion of high resolution remote sensing images and terrestrial laser scanning for improved biomass estimation of maize

2014 ◽  
Vol XL-7 ◽  
pp. 101-108 ◽  
Author(s):  
C. Hütt ◽  
H. Schiedung ◽  
N. Tilly ◽  
G. Bareth
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Terrestrial Laser Scanning ◽  
Point Clouds ◽  
Satellite System ◽  
Biomass Estimation ◽  
Digital Elevation ◽  
Elevation Model ◽  
In The Beginning

In this study, images from the satellite system WorldView-2 in combination with terrestrial laser scanning (TLS) over a maize field in Germany are investigated. Simultaneously to the measurements a biomass field campaigns was carried out. From the point clouds of the terrestrial laser scanning campaigns crop surface models (CSM) from each scanning date were calculate to model plant growth over time. These results were resampled to match the spatial resolution of the WorldView-2 images, which had to orthorectified using a high resolution digital elevation model and atmosphere corrected using the ATCOR Software package. A high direct correlation of the NDVI calculated from the WorldView-2 sensor and the dry biomass was found in the beginning of June. At the same date, the heights from laser scanning can also explain a certain amount of the biomass variation (<i>r</i><sup>2</sup> = 0.6). By combining the NDVI from WorldView-2 and the height from the laser scanner with a linear model, the R2 reaches higher values of 0.86. To further understand the relationship between CSM derived crop heights and reflection indices, a comparison on a pixel basis was performed. Interestingly, the correlation of the NDVI and the crop height is rather low at the beginning of June (<i>r</i><sup>2</sup> = 0,4, <i>n</i> = 1857) and increases significantly (<i>R</i><sup>2</sup> = 0,79, <i>N</i> = 1857) at a later stage.

scholarly journals Elaborating more accurate high-resolution DEMs using SfM workflow

2018 ◽  
Author(s):  
Alvaro Gomez-Gutierrez ◽  
Trent Biggs ◽  
Napoleon Gudino-Elizondo ◽  
Paz Errea Abad ◽  
Esteban Alonso-González ◽  
...  
Keyword(s):  
High Resolution ◽  
Laser Scanner ◽  
Point Clouds ◽  
Geographical Information ◽  
Aerial Surveys ◽  
Viewshed Analysis ◽  
Digital Elevation ◽  
Ground Point ◽  
Close Range ◽  
Ground Distance

Structure-from-Motion (SfM) photogrammetry is one of the most common approaches used to elaborate high-resolution Digital Elevation Models (DEMs) nowadays. Factors that influence the final error associated to the derived DEM are: camera-to-ground distance, camera-sensor system parameters, image network geometry, matching performance, terrain type, lighting conditions and referencing methods. Here, a strategy focused on minimizing the occlusion produced by topography and determine optimal camera locations for image acquisition is presented. This methodology is based on using a viewshed analysis implemented in a Geographical Information System (GIS) to identify the best images for the SfM workflow of a specific survey-site. The suitability of the workflow presented against conventional acquisition strategies was tested using three different datasets (one terrestrial and two aerial) and analyzing differences between SfM-derived DEM produced using: 1) a dataset acquired following conventional overlap requirements (i.e. one image every 5-10º around the target for terrestrial close-range oblique SfM and 70-60% frontal and side overlap for aerial surveys), 2) a dataset overloaded with images (i.e. one image every 3-4º around the target and >95-95% frontal and side overlap for aerial surveys), and 3) images selected using the viewshed analysis. The resulting DEMs were tested against Terrestrial Laser Scanner-derived (TLS) DEMs. SfM results showed denser point clouds for the datasets elaborated using the viewshed analysis. Differences were particularly important for the terrestrial case indicating a stronger line-of-sight effect on the ground. Point cloud density absolute differences and no-data zones in the datasets produced using the conventional strategies resulted in larger Mean Absolute Errors (MAE) in the DEMs. DEMs produced using the viewshed criteria showed lower MAEs than the conventional dataset and similar to the dataset overloaded of images. Additionally, the processing time of the datasets that used viewshed criteria was much shorter than the datasets overloaded of images.

scholarly journals A method based on structure-from-motion photogrammetry to generate sub-millimetre-resolution digital elevation models for investigating rock breakdown features

2019 ◽  
Vol 7 (1) ◽  
pp. 45-66 ◽  
Author(s):  
Ankit Kumar Verma ◽  
Mary Carol Bourke
Keyword(s):  
High Resolution ◽  
Structure From Motion ◽  
Low Cost ◽  
Digital Elevation Models ◽  
Point Clouds ◽  
Experimental Conditions ◽  
Weathered Rock ◽  
Topographic Data ◽  
Digital Elevation ◽  
Dense Point

Abstract. We have generated sub-millimetre-resolution DEMs of weathered rock surfaces using SfM photogrammetry techniques. We apply a close-range method based on structure-from-motion (SfM) photogrammetry in the field and use it to generate high-resolution topographic data for weathered boulders and bedrock. The method was pilot tested on extensively weathered Triassic Moenkopi sandstone outcrops near Meteor Crater in Arizona. Images were taken in the field using a consumer-grade DSLR camera and were processed in commercially available software to build dense point clouds. The point clouds were registered to a local 3-D coordinate system (x, y, z), which was developed using a specially designed triangle-coded control target and then exported as digital elevation models (DEMs). The accuracy of the DEMs was validated under controlled experimental conditions. A number of checkpoints were used to calculate errors. We also evaluated the effects of image and camera parameters on the accuracy of our DEMs. We report a horizontal error of 0.5 mm and vertical error of 0.3 mm in our experiments. Our approach provides a low-cost method for obtaining very high-resolution topographic data on weathered rock surfaces (area < 10 m2). The results from our case study confirm the efficacy of the method at this scale and show that the data acquisition equipment is sufficiently robust and portable. This is particularly important for field conditions in remote locations or steep terrain where portable and efficient methods are required.

Development on Filtering Algorithms of Airborne LiDAR Point Clouds

2012 ◽  
Vol 226-228 ◽  
pp. 1892-1898
Author(s):  
Jian Qing Shi ◽  
Ting Chen Jiang ◽  
Ming Lian Jiao
Keyword(s):  
Remote Sensing ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Point Clouds ◽  
Airborne Lidar ◽  
Filtering Algorithms ◽  
Filtering Algorithm ◽  
Digital Elevation ◽  
City Model ◽  
Elevation Model

Airborne LiDAR is a new kind of surveying technology of remote sensing which developed rapidly during recent years. Raw laser scanning point clouds data include terrain points, building points, vegetation points, outlier points, etc.. In order to generate digital elevation model (DEM) and three-dimensional city model,these point clouds data must be filtered. Mathematical morphology based filtering algorithm, slope based filtering algorithm, TIN based filtering algorithm, moving surface based filtering algorithm, scanning lines based filtering algorithm and so on several representative filtering algorithms for LiDAR point clouds data have been introduced and discussed and contrasted in this paper. Based on these algorithms summarize the studying progresss about the filtering algorithm of airborne LiDAR point clouds data in home and abroad. In the end, the paper gives an expectation which will provides a reference for the following relative study.

scholarly journals Elaborating more accurate high-resolution DEMs using SfM workflow

2018 ◽  
Author(s):  
Alvaro Gomez-Gutierrez ◽  
Trent Biggs ◽  
Napoleon Gudino-Elizondo ◽  
Paz Errea Abad ◽  
Esteban Alonso-González ◽  
...  
Keyword(s):  
High Resolution ◽  
Laser Scanner ◽  
Point Clouds ◽  
Geographical Information ◽  
Aerial Surveys ◽  
Viewshed Analysis ◽  
Digital Elevation ◽  
Ground Point ◽  
Close Range ◽  
Ground Distance

Structure-from-Motion (SfM) photogrammetry is one of the most common approaches used to elaborate high-resolution Digital Elevation Models (DEMs) nowadays. Factors that influence the final error associated to the derived DEM are: camera-to-ground distance, camera-sensor system parameters, image network geometry, matching performance, terrain type, lighting conditions and referencing methods. Here, a strategy focused on minimizing the occlusion produced by topography and determine optimal camera locations for image acquisition is presented. This methodology is based on using a viewshed analysis implemented in a Geographical Information System (GIS) to identify the best images for the SfM workflow of a specific survey-site. The suitability of the workflow presented against conventional acquisition strategies was tested using three different datasets (one terrestrial and two aerial) and analyzing differences between SfM-derived DEM produced using: 1) a dataset acquired following conventional overlap requirements (i.e. one image every 5-10º around the target for terrestrial close-range oblique SfM and 70-60% frontal and side overlap for aerial surveys), 2) a dataset overloaded with images (i.e. one image every 3-4º around the target and >95-95% frontal and side overlap for aerial surveys), and 3) images selected using the viewshed analysis. The resulting DEMs were tested against Terrestrial Laser Scanner-derived (TLS) DEMs. SfM results showed denser point clouds for the datasets elaborated using the viewshed analysis. Differences were particularly important for the terrestrial case indicating a stronger line-of-sight effect on the ground. Point cloud density absolute differences and no-data zones in the datasets produced using the conventional strategies resulted in larger Mean Absolute Errors (MAE) in the DEMs. DEMs produced using the viewshed criteria showed lower MAEs than the conventional dataset and similar to the dataset overloaded of images. Additionally, the processing time of the datasets that used viewshed criteria was much shorter than the datasets overloaded of images.

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