Urban environment 3D studies by automated feature extraction from LiDAR point clouds

Abstract

Research problem introduction. Both a number of necessities that require the novel technological introductions in urban studies and the challengers corresponding to these introductions have been outlined with the emphasis on the urban remote sensing tools. The research goal of this text is to outline the authors’ original contribution to the algorithmic content of the automated feature extraction upon the urban environment modeling, as well as to represent the original web-software for urban studies. AFE methods in the building detection, extraction and 3D reconstruction within the LiDAR pipeline: a thematic overview. The overall AFE algorithmic approach has been summarized proceeding from an extensional literature review due to the feature extraction from raw lidar data. A sample of the composite model of an urban feature extracted, the overall AFE algorithmic flowchart, and few MSL processed results have been visualized. Feature detection, classification, segmentation and reconstruction have been presented as constituents of the united LiDAR pipeline. EOS LiDAR Tool (ELiT) and our key original algorithmic approaches to the AFE issues. The web-software has been developed on the base of the outlined multifunctional research approach. This software has several basic functionalities within the distributed information system: building extraction, building extraction in rural areas, change detection, and digital elevation model generation. Two basic algorithmic approaches implemented in the software have been explained in details: High Polyhedral Modeling provided by the Building Extraction tool, and Low Polyhedral Modeling provided by the Building Extraction Rural Area tool. The extensive usage of the Voronoi diagram for cluster adjacency on the finalizing modeling stage has been provided as our original update of the existing LPM methodology: its applying for the roof cluster adjacency determination and for separation of coplanar clusters, applying limited diagram for avoiding side effects of adjacency determination, its applying for the awning / overhand identification. ELiT Geoportal. The EGP has been depicted as a type of web portal used to find, access, and process LiDAR geospatial both primary, and derivative information, as well as to provide the associated geographic services (display, editing, analysis, etc.) via the Internet. The key characteristics of our Geoportal have been listed as well as some illustrations provided for the uploaded projects. Conclusion and future works. The automated feature extraction from lidar data technique has been presented with the authors’ updates as a highly promising solution for the multicomponent simulation of urban environment, that can be used for different applications for cities. The use-cases for the EGP have been outlined as hot issues: Population estimation with building geometries; Energy demand for heating and cooling; Visibility analysis in urban environment.

Automated Extraction of Heavyweight and Lightweight Models of Urban Features from LiDAR Point Clouds by Specialized Web-Software

“…We can emphasize as a strong point of our overall R&D approach just this joint employment of these two technically different methods within the united building detection, extraction, and modeling methodology, what is resulted further in the relevant software elaboration with two different tools -Building Extraction (BE, for a case of HPM), and Building Extraction Rural Area (BERA, for a case of LPM). Some common features of both approaches and relevant software tools have been already presented in some of our previous publications, although we have not made yet an emphasis on an allocation of both HPM, and LPM within a unified workflow [1,4,43,102]. Since in many cases Airborne LiDAR survey relies on existing territorial regularities of urban areas, it is often provided consequentlyfrom city central parts to outskirts.…”

“…The Voronoi diagram has been applied for the roof cluster adjacency determination and for separation of coplanar clusters, while the limited Voronoi diagram has been used for avoiding the side effects of the cluster adjacency determination. Also, the Voronoi diagram has been applied for the reliable identification of some traditional architectural constituents such as building awnings and or building overhands [102].…”

“…ELIT 3D city models as many other 3D models appear to be predominantly used for display; however, they are being increasingly employed in number of subject areas and for a large range of tasks beyond the visualization. In our previous publications, we sought to understand and present several use cases regarding their presentation not only on the ELiT Server, but also on the ELiT Geoportal with further utilization of these City GML LOD1 models for some tasks within and beyond model display [4,102].…”

“…A common definition of the EliT Geoportal (EGP) as a cloudbased application has been already done in the previous subsection of this text. We already explained in one of our previous publication the necessity of a geoportal as a robust solution for the web-GIS software promotion [102]. EGP is a kind of web portal used to transform occasional visitors of the EOS LiDAR web-site into the warm leads.…”