4

I am trying to make a map that displays both an incidence rate of a type of cancer and also display at the same time a percent of the population per state that has a certain vaccination. I've added both the data sets as CSV files and have joined them so that they all show up in the attribute table. But I can't figure out if there is a way to display both at once or if this isn't possible.

The bottom layer of incidence rate is already displayed as a graduated layer using color and ideally I could display the vaccine rate on top as a transparent layer using dots, etc.

If this is not possible, just let me know.

5

It sounds like what you're trying to do is create a bivariate choropleth map as you're essentially attempting to display two continuous values within each boundary simultaneously. There's a good explanation on how to do this on Josh Stevens blog.

3

You could just stick with graduated colors for the number occurrences of the cancer, and then label the features with the percentages.

The image below shows harvest numbers for each region, with the region's percentage of the total harvest as a label.

graduated colors with percentages

3

A simple method would be to duplicate the layer in the Layers panel and style the bottom one to show incidence rate with a graduated colour scheme, and the top one to show vaccine rate with your dots or whatever.

  • So to do this would I duplicate the shape file and then have one that displays the chloropleth and then the top one is a transparent layer with dots or whatever? – Sarah Powell Feb 16 '16 at 3:25
  • Yes, right-click on the layer name and select 'duplicate'. This doesn't save a new copy, it's the same layer, just displayed twice. To avoid corruption, only edit the original. You can then style them totally separately and add each into your legend etc. – SpatialSuccess Feb 16 '16 at 3:30
  • Is there anyway to make the dot fill graduated? As in more dense dots correlates with a higher value? Or not really? – Sarah Powell Feb 16 '16 at 18:43
  • Yes, you can select data-defined values for the dot fill horizontal and vertical intervals. You may need to experiment with using expressions to get it looking right, eg. "incidence" *100 or similar. – SpatialSuccess Feb 17 '16 at 8:59

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