Light Mapping

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Street lights consume an enormous amount of energy. A city or municipality therefore can benefit from an efficient use and placement of public lighting. On the other hand it is interesting for cities to know, where public places are badly lit, which could result in a higher number of crime facts or dangerous traffic situations at these locations.

During a night flight EUROSENSE acquires aerial imagery with a light sensitive camera. These “night images” are processed in the same photogrammetric production chain as “day images”, resulting in a detailed “night orthophoto” and light maps. The map is calibrated using luminance measurements executed on the terrain and a legend in absolute luminance values in Candela/m² is created.

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Light maps showing the amount of light are an important policy instrument for cities and municipalities with regard to:

Energy saving: locating excessive or inefficient lighting and potential savings;

Safety: locating poorly lit areas, which may lead to increased crime and/or traffic hazard;

Light pollution: pinpoint overexposed areas by both private and public lighting elements.

To allow policy makers to easily interpret the maps, EUROSENSE usually creates two kinds of maps based on the European guidelines for public lighting (EN 13201): the “overexposure map” and the “EN classification map”. On request of our clients we can also create other related maps. The “overexposure map” indicates overexposed areas in colour, as well as the European public lighting classes in grey values. The “EN classification map” focuses on the non-overexposed areas, so that a distinction can be made between the different public lighting classes and luminance values displayed by colours. For each zone in the public space it is possible to determine, whether the class rating on the map matches the desired class. If the luminance value is too high, at this location energy can be saved. If the luminance value is too low, this can reduce the safety (traffic and crime).

The data acquisition for light mapping is often combined with a thermography flight for roof insulation assessment (click here for more information). This has the big advantage that the flight costs can be reduced because they are spread over two separate products: the thermographic map and the light map.