Van Buuren House Orthophotographic Survey

Collaborating institution & subvention: Direction des monuments et sites de la région bruxelloise (actually Urban.brussels)
Budget: 20.000 €

This work constitutes an orthophotographic survey of the dining room, loggia, music salon, cozy corner, hall, office, and workshop of the Van Buuren couple’s house at 41 Avenue Léo Errera in 1180 Brussels. Orthophotography uses photographic support as a tool for surveying and observing architectural elements. With the advancement of digital sensors, a digital single-lens reflex (DSLR) camera can extract a wealth of information about a building, including its materials, geometry, and measurements. In the case of a facade survey, a photograph taken with a 12-million-pixel sensor has the potential to reveal twelve million colorimetric details of the subject and an equal number of two-dimensional spatial coordinates. However, image processing is necessary to remove distortion effects inherent to the internal geometry of cameras. The results obtained from this process are referred to as orthophotography. Image correction involves both three-dimensional and two-dimensional processing. Before a photograph can be properly processed, it is essential to position and align it within the virtual space of the studied scene. This operation, known as camera calibration, determines the metric and spatial values contained in our representation.

Although orthophotographs generally exhibit both visual and metric coherence (with a precision level ranging from 0.5 to 2 centimeters) when compared to elevations and plans, some cannot be regarded with the same dimensional quality. The complex spatial configuration of the Van Buuren Museum and the narrowness of the spaces necessitate the use of a wide-angle lens, which, despite post-processing, compromises the metric accuracy of certain orthophotos. This situation is particularly evident in floor surveys. “Shadow zones” (areas with missing or reconstructed data) result from the presence of “parasitic” elements—such as immovable furniture, paintings, and sculptures—in the orthogonal projective system of the photos. Whenever possible, some of these zones have been reconstructed to maintain graphical consistency throughout the document.

The orthophotographic sections result from a combination of orthophotographic views extracted from specific spaces within the Van Buuren Museum, along with the projection of the building’s overall geometry in cross-section. Each orthophotographic projection plane corresponds to a cross-sectional plane located just in front of the elevation of the object it represents. The complete section is thus an aggregation of local projection planes situated at different depths within the structure.

For clarity within the space, we opted for a volumetric section system along the North-South axis. This allowed us to precisely cut through the center of the ridge axis while representing a maximum number of depth planes. Additionally, this approach highlights the communication between the hall and the music salon. As a result, we obtained a relatively complex global section system that emphasizes how the space is perceived, both geometrically and in relation to other areas. The geometric drawing is derived from a basic survey of the building, suitable for a drawing scale of 2 cm/m.