Ground surfaces

NoiseModelling is a tool for producing noise maps. To do so, at different stages of the process, the application needs input data, respecting a strict formalism.

Below we describe the table GROUND, dealing with the land use type, with an associated ground absorption coefficient (G).

The other tables are accessible via the left menu in the Input tables & parameters section.

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Table definition

Warning

In the list below, the two columns are mandatory

  • THE_GEOM
    • Description: 2D geometry of the surfaces (POLYGON or MULTIPOLYGON)
    • Type: Geometry
  • G
    • Description: acoustic ground’s absorption (from 0 : very hard to 1 : very soft - see table below)
    • Type: Double
G values for different types of ground (extracted from “Common Noise Assessment Methods in Europe (CNOSSOS-EU)”, p86)
Description G
Very soft (snow or moss‐like) 1
Soft forest floor (short, dense heather‐like or thick moss) 1
Uncompacted, loose ground (turf, grass, loose soil) 1
Normal uncompacted ground (forest floors, pasture field) 1
Compacted field and gravel (compacted lawns, park area) 0.7
Compacted dense ground (gravel road, car park) 0.3
Hard surfaces (most normal asphalt, concrete) 0
Very hard and dense surfaces (dense asphalt, concrete, water) 0

Topology

At a given point, there can only be one value of G. Consequently, in the GROUND table, the geometries must not overlap.