I'm creating an open map layer of race in the United States using
Census Data. This layer will be publicly available in the near future as
"Justice Map". I'm generating tiles with TileMill. I will be creating
tiles for Google Maps zoom levels 0-13 -- all the way down to the block
How should I choose my intervals for coloring the map?
The problem is that all the non-white racial groups are heavily
concentrated in medium or small sized areas (notably Asians and Native
Americans). I don't want to distort the geography to make the size of a
state proportional to its population, as that would make it hard for
other people to use this open map layer.
My race layers are Black, Asian, Native American, Hispanic, White
Non-Hispanic, Multi-Racial, other race, and Hawaiian or Pacific
So far I'm planning on using a sequential color scheme from colorbrewer2.org and nine categories.
Equal Breaks: it makes the map look too empty for most racial groups.
Jenks Natural Breaks: also makes the map too empty.
Percentile: map looks nice, but emphasizes very small differences. For
percent Black and census tracts it has breaks at 0.4%, 0.8%, and 1.6%.
Should I use one of these methods? Or is there another one that I can use?
I'm thinking of using my own method which would be based on percentile, but merge some of the lower categories together so that the tiny differences would not be emphasized as much.