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I have a simple 2-color map showing which candidates won in which precinct. Now I want to make one showing margin of victory within a precinct. So if candidate A won by a lot it would be dark green, if candidate A won by a little it would be light green, if candidate B won by a lot it would be dark yellow and if candidate B won by a little it would be light yellow. (These are local elections so red and blue don't make sense). I used color brewer to pick my initial two color scheme. I have zero design sense. How do I go about picking the colors for the margin of victory map?

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You would probably have to standardize your data first so you can define "a lot" or "a little" by a number/ratio/percent. Then you could define your margin of victory upper/lower class breaks and then color your classes accordingly. –  user21646 Mar 19 at 1:55
    
@JasparKatt can you say about the appropriate way to standardize this kind of data. How do I decide what the bins should be? –  akh2103 Mar 19 at 2:02

2 Answers 2

up vote 2 down vote accepted

If you need to get color dynamically on a website, I would give you the advice of using the excellent chroma.js library. The library is easy to use and implements a scale mechanism which would fit to your needs :

scale = new chroma.ColorScale({
colors: ['#F7E1C5', '#6A000B']
})
scale.getColor(0.23)
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There is the ColorBrewer Option in QGIS:

From the Layer Properties > Style > choose Categorized > from Colour Ramp choose New Colour Ramp > Select type Colour Brewer:

enter image description here

Or use the ColorBrewer website: http://colorbrewer2.org/

Pick a diverging colour scheme, maybe 5 data classes, then pick a colour scheme...

You can use those colours in whatever your mapping client is.

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