Noise maps
A noise map is a graphical representation of sound levels for a given location and relative to a given period of time. This descriptor of the outdoor ambient noise is expressed by the indicators: Lden (average long-term sound level associated with discomfort in the period of 24 hours of the day) and Ln (average long-term sound level associated with discomfort during the night, from 23h00 to 7h00). For each of these indicators, a drawn piece is produced, a map, which draws noise isolines – lines that join points with equal sound level, called isophone, which corresponds to a certain class of values expressed in decibel - dB(A).
The noise map consists of two distinct drawn pieces, one for the Lden indicator and one for the Ln indicator.