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peshawa Nov 05, 2019 02:22 PM

I am studying master degree in cartography, in one of our project it is required to create environmental map of a town. Can you please provide me with the color schemes and classification methods used in mapping of noise, temperature, humidity, and solar radiation?

Replies (1)
EEA Nov 06, 2019 02:39 PM
Dear M. Peshawa,

Thank you for contacting the European Environment Agency (EEA).

We haven't defined colour schemes for environmental topics as such but we are happy to share with you some of our basic guidelines.

1. Important rule:
We would suggest being careful when creating maps using the “traffic-light” red-yellow-green colours. People with a colour-deficiency may have difficulties to distinguish between red and green. We are using ‘add-on’ to Google-chrome called ‘Spectrum’. This is a small application that visualise how the colours will change for people with different kinds of colour deficiencies.

The map that you can find at https://www.eea.europa.eu/d[…]n-2014#tab-data-references, is used in the EEA Air Quality report and the colours are meant to visualise three states: Good (greenish), moderate (yellow) and bad (reddish). For this map there is a constraint mentioned in the legislation defining a threshold for the moderate state. So, for the Air Quality-maps we need to use three colours. The latest version of this map was made with bluish colours even though bluish is usually reserved for water or (cold) temperature themes. See: https://www.eea.europa.eu/[…]/o3-indicator-somo35-in-1 .

We could also suggest creating maps as 'choropleth' maps using reddish or purple colours. Red and purple colour indicate that something is going from ‘bad’ (light) to ‘worse’ (dark). A map could be made with greenish colours but the colour message is different; we are saying that something is going from good to better. We would recommend not to use greenish colours to show an worsening situation.

Most often red colour will be perceived as a ‘bad’ situation and green will be perceived as a ‘good’ situation – using these two colours together can cause some challenges, as mentioned above.

Nevertheless, note that sea biologists usually want to visualise algae as green because this is the colour of the algae. So, when there is a high concentration of sea algae (which is considered as a bad situation) the map will be dark green and when there are no algae it will be visualised as red which in their case means ‘good’.

2. Use green and replace red with purple
Red can be replaced by purple – dark purple being considered as very bad and dark green as very good. People with the protanopia-deficiency can clearly distinguish between these colours. See: https://www.eea.europa.eu/[…]/predicted-climate-change-impact-on .

3. Maps showing temperatures and solar radiation
Use reddish colours to visualise the heat and drought and bluish colours when visualising the rainfall, wet or cold areas . Please find some samples at:

4. Noise
We haven’t defined colours to use for noise. In the below maps we have used green indicating quiet areas and orange/red to indicate the highly noisy areas of Europe. Note that these maps were made before we started considering the colour-deficiency matter.


We do hope that this information may be useful for you.

With kind regards,
EEA Enquiry Service