LiDAR-based method for analysing landmark visibility to pedestrians in cities: case study in Kraków, Poland

ABSTRACT

We propose a method for analysing landmark visibility from a pedestrian’s perspective. A case study is performed in Kraków, a city with many architectural monuments, where airborne LiDAR is used to model both buildings and urban greenery. The proposed method involves preliminary and detailed stages. The preliminary stage entails an inverse analysis (I–Vis) that departs from the typical visibility analysis to enable the use of landmarks as observers instead of targets. I–Vis results in paths with high landmark visibility. The detailed stage involves the use of a virtual panorama (V-Pan) to determine the visual exposure of the landmarks. Landmarks considered visible by I–Vis are generally consistent with landmarks identified by V-Pan. Discrepancies occur when trees appear in the near field-of-view. In addition, the accuracy of the skyline length and visible landmark surface area is evaluated against ground observations. The obtained results show that V-Pan can evaluate landmark visibility with an accuracy of approximately 75%. The key contributions of the work to visibility analysis of urban landmarks are in the inverse viewshed strategy and evaluation of the visual exposure parameters on LiDAR virtual panoramas.

KEYWORDS:

• Visibility analysis
• cityscape
• landmarks
• LiDAR data
• visual exposure

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data and codes availability statement

The data and codes that support the findings of this study are available at 10.6084/m9.figshare.14853636

Individual’s contribution

Krystian Pyka: conceptualization and methodology of V-Pan, data preparation, supervision, formal analysis, investigation

Radosław Piskorski: conceptualization and methodology of I-Vis, data preparation, original draft preparation, related work review, investigation

Aleksandra Jasińska: collection of reference data, manuscript editing and updating

Additional information

Notes on contributors

Krystian Pyka

Krystian Pyka graduated in 1978 from the Faculty of Mining Surveying of the AGH University of Science and Technology in Kraków, with a M. Eng. in Geodesy and Cartography. He obtained a PhD in 1986 and Habilitation in 2006. In 2014, he was granted the title of Professor in Technical Sciences. He was an Assistant Professor in the Department of Photogrammetry from 1978 to 1986, a post-doctoral researcher from 1986 to 2007, an Associate Professor from 2007, and a Full Professor in 2014. He worked for five years for the Chief Office of the Małopolska Region as a regional geodesist. He was the head of the Department of Geoinformation Photogrammetry and Remote Sensing of Environment from 2008 to 2016. He has authored/co-authored more than 80 publications pertaining to remote sensing and geographic information systems. Two of the most important publications are ‘Wavelet-based local contrast enhancement for satellite, aerial and close range images’, Remote Sensing (doi:10.3390/rs9010025 (2017, author)) and ‘Mobile laser scanning systems for measuring the clearance gauge of railways: state of play, testing and outlook’, Sensors (doi:10.3390/s16050683 (2016, co-author)).

Radosław Piskorski

Radosław Piskorski received a B. Eng. in Geodesy and Cartography from the AGH University of Science and Technology in Kraków, Poland in 2013, a M. Eng. in Geodesy and Cartography from the same university in 2014, and a PhD in civil engineering and transport from the same university in 2020 (thesis entitled, ‘Visibility analysis in urban space using airborne laser scanning’.) His research interests include geographical information systems, urban analysis, and cartography. Currently, he is a postdoctoral researcher for the Religion Urban Mapping project at Jagiellonian University.

Aleksandra Jasińska

Aleksandra Jasińska received a B. Eng. in Geodesy and Cartography from the AGH University of Science and Technology in Kraków, Poland in 2020, and a M. Eng. in Geodesy and Cartography in 2021. Currently, she is a PhD student at the same university. Her interests include the integration of data from classical photogrammetric measurements and mobile devices (UAVs and smartphones) to form an inventory of natural or architectural monuments. She is a co-author of an articles entitled, ‘Comparison of DEMs of the Łącka Dune obtained using different techniques’.