Often when you use a filled map in Tableau and colour it using a particular measure the map looks rather bland. This is caused by a couple of countries having particularly high or low values and therefore skewing the colours. If the high/low values are for small island countries then they will be practically invisible and the whole map will have pretty much the same colour.
Here is an example of a filled map coloured by a measure ‘Merchandise trade as a percentage of GDP’. It looks very bland because most of the high value countries are small islands.
This is a map used one colour – light to dark green. I will later show also an example with 2 colours on a diverging scale.
It is relatively easy to make this map more interesting by dividing all the values, for example, into 10 groups (deciles) by the order of magnitude of the value that we want to display. So not only the highest e.g. 2 countries will be the darkest but so will also be 10% of other countries with the highest values. Each colour group will have the same number of members and we can therefore expect to see more variety of colours on the map.
What to do:
- Create a calculated field and call it e.g. ‘Decile’
- The formula to use is:INT(10 * (RUNNING_SUM(SUM([Number of Records])) – 1) / TOTAL(SUM([Number of Records]))) + 1You can easily adapt it by changing the number 10 into other numbers to get quartiles (4), percentiles (100), n-tiles (n) etc.
- Put your calculated field onto the colour shelf
And voilla, this is the result – much more vibrant and interesting map:
The results are even more striking if you use a map with diverging colours: