Creating 3D City Models in a Single Flight

Efficiency in Vertical and Oblique Aerial Photography Collection

In the last decade, oblique camera aerial systems were introduced into many diverse aerial imaging applications. System uses include but are not limited to: multi-perspective desktop viewers, visualization of buildings roofs and façades from a 360-degree perspective, realistic texturing of 3D City models, and measurement of building heights in monoplotting mode.

Today urban planners and decision makers rely on 3D City modeling to support a wide variety of initiatives and actions. 3D city models are used to prepare for changes in city structures, population growth and urban planning, preventative measures for natural and industrial disasters, inhibiting overuse of finite resources, incorporating sustainable practices, and more. City planners therefore require a reliable database that can be easily modified over time in order to gain a holistic look at the urban environment. An immediate advantage of acquiring oblique images is the possibility to view elements that are generally occluded or not visible in the vertical views.

Aerowest GmbH has provided acquisition and processing of geospatial data from aerial photographs since 1970. In February 2017 they integrated eight Phase One Industrial 100MP cameras into an IGI UrbanMapper for acquiring data for aerial 3D models in a fast, efficient, and cost-effective way.

Image: 3D Mesh Model – Courtesy of Aerowest. 2018 ©

Generating Online City Models

Each Phase One Industrial camera contains a 100MP CMOS sensor and each lens utilizes innovative RS shutters. A fast capture rate of 0.6 sec per image, and the high performances of Phase One Industrial RS lenses, integrated with an IGI processor, lead to outstanding image quality. The system is able to provide a 2cm Ground Sample Distance (GSD) at 400m flying altitude; 5cm GSD at 1000m flying altitude. A forward overlap of >80% is achievable at 120kn flying speed.

The UrbanMapper with its eight Phase One 100MP aerial cameras captures a huge amount of data. Processing this data and generating a comprehensive and detailed model out of it takes time. Aerowest uses SURE Aerial software by nFrames GmbH and PHOTOMESH software by Skyline Software Systems Inc. side-by-side to produce textured 3D models of cities. The oriented images can be processed with any matching or photogrammetric software on the market. Even smaller municipalities can now achieve cost effective, high-quality 3D city models as well as orthophotos with an accuracy of two to ten centimeters.

Multi-perspective aerial imaging opens many new opportunities in geodata based applications. Aerial imaging with qualified cameras offers the fastest way to reproduce digital 3D representation of reality for all kinds of planning, surveying or visualization.

3D city models are generated fully automatically from high-resolution multi-perspective aerial photos. A coherent surface, the so-called 3D mesh, is derived from the 3D PointClouds and textured throughout. Alternatively, 3D buildings can also be captured and textured using object-oriented methods. In this way, photorealistically modeled 3D buildings can be linked to any material data (e.g. ALKIS). Aerowest delivers and updates textured city models in CityGML format as standard.

Image: UrbanMapper by IGI – Courtesy Aerowest GmbH. 2020 ©