In this paper the approach for an acoustical model based monitoring network is demonstrated. This network is capable of reconstructing a noise map, based on the combination of measured sound levels and an acoustic model of the area. By pre-calculating the sound attenuation within the network the noise map can be shown in real-time. The monitoring network offers an analysis tool for instance for industry or legal authorities. Alternatively, it can be an extension to the EU legislated noise maps. In principle the monitoring network works as follows. Battery powered microphones are deployed in an outdoor area. SPL's are measured in octave bands. Wireless communication and multi-hopping is used to collect the data at a central station. The SPL values are used to localize non-directional point sources, while accounting for obstacles and meteorological effects in the sound attenuation. The final result is a list of reconstructed sources with their locations and strengths and a noise contour map. The monitoring network is scalable and seems feasible and useful for large areas.