[Talk-GB] The OSM UK map

David Woolley forums at david-woolley.me.uk
Wed Nov 15 11:33:24 UTC 2017

On 15/11/17 01:53, Gervase Markham wrote:
> Can we please have blue motorways and green A-roads?:-)  Or do people
> not like green A-roads because so many other things are green?

Whilst the OSM map renderings probably fall in a grey area, between 
public services and private hobby, for any map rendering provided as a 
service to the general public, especially in a part of the world with a 
high prevalence of red-green colour blindness, using just a red-green 
distinction would be illegal under anti-discrimination law.

I'm not colour blind, but I rather suspect that most OSM cartographers 
have not considered people with vision defects in their decisions.

The other accessibility issue that is likely to arise is low colour 
contrasts.  Web sites will fail accessibility guidelines, if, when you 
reduce them to black and white with the same luminance components, there 
is insufficient contrast.

The UK philosophy on law is to have laws which say things will be safe, 
accessible, etc., and then use non-legislative standards (building 
regulations approved documents, W3C's Web Content Accessibility 
Guidelines, etc), to try and judge whether the law is being obeyed).  As 
such, you will not find a law that explicitly states you can't rely on 
just a red-green distinction.

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