NOISE MAPPING PROCESS Dr Bernadette McKell Hamilton & McGregor.

NOISE MAPPING PROCESS

Dr Bernadette McKell

Hamilton & McGregor

What We Have Mapped?

•Agglomerations over 250,000 inhabitants (including industry and ports)

•All major roads carrying more than 6 million vehicles a year;

•Major railways with over 60,000 rail passengers a year

•Major airports with over 50,000 movements per year.

What Have Mapped Within Agglomerations?

•Industry and ports

•All roads within agglomerations with flows of 1000 vehicles or more per day (the lower limit is equivalent to 0.35 million passages per annum).

•Every railway which is likely to produce noise levels of greater than 55 dB Lden or 50 dB Lnight at 4m above ground level (therefore all railways).

DefinitionsLden : 24-hr Leq calculated for an annual period, weighted for nightand evening.

Levening :The A-weighted long-term average sound level as defined in ISO 1996- 2: 1987, determined over all the evening (19:00 – 23:00) periods of a year

Lnight : The A-weighted long-term average sound level as defined in ISO 1996- 2: 1987, determined over all the night (23:00 – 07:00) periods of a year

dBLnighteveningday LLL

den

10

10

10

5

1010 10*810*410*1224

1log*10

The logarithmic of Lday Levening and Lnight including penalties for the night and evening periods

Noise Source

Methodology

Road CRTN+TRL backend LA18(hr) to Lden correction

Railways CRN + correction to take account of rail/wheel roughness

Airport .csv files (CAA for Glasgow, Edinburgh and Aberdeen and Bickerdike Allen for Prestwick)

Industrial & Ports

European Commission Working Group Assessment of Exposure to Noise (WG-AEN) GPG for Strategic Noise Mapping and the Production of Associated Data on Noise Exposure

Qualifying Road Study Areas

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Overall Area

Total Study Area (incl buffer = 4494 sq km)

Inliers and Outliers

Total area outside Agglomerations =3659 sq kmTotal road length outside Agglomeration = 1635 km

Edinburgh AgglomerationTotal area of Edinburgh Agglomeration: = 274 sq kmTotal length of road within Edinburgh Agglomeration =496 km

Glasgow Agglomeration

Total area of Glasgow Agglomeration =766 sq kmTotal length of road within Glasgow Agglomeration =1483 km


Qualifying Railways Study Areas


Edinburgh AgglomerationTotal area of Edinburgh agglomeration = 274 sq km Total Length of Railway tracks within Agglomeration =163 km

Glasgow AgglomerationTotal area of Agglomeration = 766 sq km Total length of railway tracks within Agglomeration = 652 km

Outliers and InliersTotal area of outside Agglomeration =: 422 sq km

Total length of railway tracks outside Agglomeration = 205 km


Due to OS licence conditions, you/your agent may only use this map for official business dealings with the Scottish Government. If you wish to use the map for other uses, you must first obtain a separate licence from OS.© Crown copyright. All rights reserved Scottish Government 100020540 2007.

Ground modelling

Primary Data Sources :

•OS Master Map•Nextmap DTM, DSM•LiDAR Data •ITN Road Network

Data, Process and Optimisation



Main primary data source for the ground objects



OS Data represents the real world accuracy



2D Buildings are extracted from OS Master Map data



Master Map with 2D Buildings ( Glasgow City Centre Area)



3D Glasgow Urban Model

Building height assigned from LiDAR data

1m LiDAR data source: Geoinformation group, UK



Width Model

Railway tracks are modelledaccording to constant width

Road are modelled according to actual width



NextMap DTM

Advantages for Noise Mapping

•Better accuracy then contours •Compatible with noise modelling software

Problems•Contains too many points•Create problem in noise calculation in Larger area• Heavy file size

Data Required optimization

Total number of points (pixels) in the City Centre Area: 145994


•Total number of points are reduced from 145994 to 11682 ( 12 times reduction)•File size reduced to 10MB to 2.5MB

Total number of points (pixels) in the City Centre Area: 11682


Model Comparison

3D Ground model from original points

3D Ground model from optimised points

Insignificant difference between models M2 is compatible, fast and accurate for noise modelling

M1

M2


3D buildings ground model

•Building heights from 1m Lidar•Ground Model from 5m NextMap



3D Noise Map Lden Glasgow City Centre Area



Final Noise Map



http://www.scotland.gov.uk/Publications/2007/08/24141743/0

NOISE MAPPING PROCESS Dr Bernadette McKell Hamilton & McGregor.

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Transcript of NOISE MAPPING PROCESS Dr Bernadette McKell Hamilton & McGregor.