For the calculation of the noise values upon which the present maps are based, the input data available to the State of Berlin for the reference year 2011 were used.
The mapping zone covers the area of the State of Berlin, amounting to 892 km². The examination covered the noise load exposure of 3,460,725 inhabitants.
For the Level 1 noise map (2007, Map 07.05. Strategic Noise Maps (Edition 2008)), an overall terrain model was compiled from various separate models (DGM5, DGM25, elevation points of railway lines), and attenuated into levels.
Moreover, the upper and lower edges, respectively, of the railway embankments and cuts were ascertained from stereo aerial imagery with the precision of < 0.5 m, and integrated into the terrain model as contour lines.
For the current Level 2 noise map, the Level 1 terrain model was adopted, and, on the basis of DGM2 and measurements, also supplemented to show the terrain edges along embankments, cuts and underpasses of roads. The edges along railway embankments are to be checked and corrected if necessary.
The measurement of these edges is carried out as follows:
- Importation of the current aerial imagery (Aerial Imagery Flight Berlin 2011, digital colour aerial photographs [8 bit], resolution approx. 10 cm), in addition to orientations in the ImageStation SSK evaluation system of Intergraph;
- Interactive evaluation of aerial imagery models, and ascertainment of the upper and lower edges of terrain protrusions, underpasses and noise protection facilities in MicroStation DGN files;
- Further processing of the various attributed files in GIS.
Noise Insulation Facilities
The location, elevation and absorption behaviour of noise protection facilities on roads and rail lines were reviewed and updated. For federal motorways, supplemental noise protection facilities were digitalized on the basis of information on their existence, elevation, material, and central axis length. New noise protection facilities on local roads were adopted on the basis of planning documentation. Moreover, corrections of the data were undertaken on the basis of local knowledge, and in consultation with the client.
Tunnels – Railway Stations
Tunnel facilities were depicted in the calculation model by interruptions in route lines. Tunnel openings were not modelled as separate noise sources.
Noise levels for railway traffic in railway stations were calculated as is equal to those on open tracks, without accounting for reduction in speed. The blocking of noise by railway platforms and railway station buildings was not taken into account in the calculation of rail traffic noise. For other types of noise, railway station buildings were accounted for as obstacles.
Bridges across roads and waters were taken into account in 426 sections where the high position of a road has a relevant acoustic effect on the neighbouring built-up area. A reflecting bridge platform was modelled across the width of the road in each of these cases.
When using the noise map, the following must be observed: bridge structures are not included in the surface of the terrain; rather, they rise above the terrain. Noise maps are calculated at a height of 4 m above the terrain, and can therefore be related to the area below a “noisy” road bridge which acts as a sound barrier, with accordingly low local immission levels.
The floor plans of 535,920 buildings, with specification of the number of floors and the building uses shown in the Table below were taken from the Automated Real Property Map (ALK) of the City of Berlin (as of June 2011) (see Table 2):