Traffic Noise in Helsinki
This visual data mining case study is based on open data published by the Environment Centre of Helsinki (Helsingin Kaupungin Ympäristökeskus). The original data set is available at the Helsinki Region Infoshare and contains detailed information about city noise levels as a zipped Esri shapefile. Detailed description of the data and related research can be found from the summary report available at the noise study project web pages (mostly in Finnish).
The noise data set is a great example of open data which could be very valuable to common people. For example, families looking for a quiet neighborhood in Helsinki would probably want to check local traffic noise levels before buying a house. Unfortunately, the available information is given in rather difficult format for a quick view (see the discussion below). Therefore, we decided to represent the same data as a heatmap on Google Maps generated with the HeatMiner® visual data mining tool.
Traffic noise during daytime (07-22)
The following heatmap shows the average traffic noise levels (LAeq) during daytime (between 07-22). Click the image to open a full page view on Google Maps. Colors of the heatmap indicate the average noise levels so that red areas are the noisiest. Click colored areas with the right mouse button to view the related decibel range.
Click to open interactive full page view
The heatmap shown above was generated using the HeatMiner tool based on the shapefile 'helsinki_tieliikenne_LAeq_paiva.shp' (23.2 MB!). HeatMiner was able to summarize the data into a lightweight html+javascript file (600 KB) which is fast to download and view.
Traffic noise during nights (22-07)
The heatmap below shows the corresponding traffic noise levels (LAeq) during nights (between 22-07). Again, click the image to open a full page view on Google Maps and rightclick colored areas to see decibel ranges.
Click to open interactive full page view
The heatmap above was based on the shapefile 'helsinki_tieliikenne_LAeq_yo.shp' (15.5 MB). The size of the corresponding HeatMiner heatmap file is only 474 KB.
Heatmaps4Finland
You can now generate detailed traffic noise heatmaps for your region of interest with the Heatmaps4Finland application! Free evaluation available.
Motivation for this work
In theory, one could simply download the original data set and open the files with some tool that can read Esri shapefiles to view similar heatmap visualizations with even greater amount of details. Easier said than done. The size of the zipped data set is 57.3 MB and the biggest shapefile (helsinki_tieliikenne_LAeq_paiva.shp) is 23.2 MB large containing extremely detailed vector graphics. Ordinary Internet users probably do not have the skills, tools or patience to handle that kind of data files.
Alternatively, one could check the attachments of the noise study summary report. Each of those one-page PDF files shows a highly detailed heatmap visualization. Unfortunately, the PDF files are very large (the biggest is 9.17 MB) and viewing them is painfully slow. For example, try this one.
In order to make the research results beneficial for the widest possible audience, the data should be presented in a form which is fast, easy and fun to use. Common people just wants to view interesting and beautiful infographics with their iPads or smart phones and share links with their friends. Nobody wants to install complex tools or learn to use them - a web browser should be enough to access the information.
For these reasons, we decided to represent the data as a heatmap on Google Maps and hope you find the visualizations fascinating and useful. Have fun!
Comments?
Please send your comments to the author Pauli Misikangas.
Would you like to see your data as a heatmap on Google Maps?
HeatMiner® is a commercial visual data mining tool that is available as-a-Service via the Cloud'N'Sci.fi marketplace. Currently, we are serving only pilot customers, but public general-purpose solutions for generating Google Maps based heatmaps will be released at some point.
We are looking for new pilot customers who would like to visualize data as a heatmap. In case you are interested, please contact Pauli Misikangas.
See also
In case you are planning to make your own studies with the original noise data set or want to know more about the challenges related to those large shapefiles, take a look at the excellent document "Pääkaupunkiseudun liikennemeluvyöhykkeiden haltuunotto" by Jukka Rahkonen.
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