- Shapefiles: Select a decade of the census to represent in your map. These shapefiles have been rendered as WGS84 files–a format that will work with many geospatial tools for the web.
- Mapshaper: Add all of the files from that decade’s folder to Mapshaper. After you have imported the files, simplify them. Using the default options is fine. You’ll want to reduce the complexity considerably to about 1%. Export them as GeoJson.
- Flourish: Select the blank map template. Import your GeoJson file as your data by overwriting the current data. Label your Geometry column (“Geometry”) and your Name column (“NHGISNAM”)
- Data: Select the decade of data that you want to represent. Open that CSV file, and delete the first row (the one with the codes). Save the CSV under a new name. You may make other edits to limit the columns or rows of data available.
- Return to Flourish. Import your edited CSV by MERGING it with your existing data. Match up the GISJOIN column headers to create the merge. In the right column, input the column that you would like to represent with the region shading. Select the columns of data you would like to include in the roll-over popup. If you want to use more than one, separate those column ids with commas.
- Preview your map. Use the options in the right column to adjust the appearance of your map.
- Pay attention to the “Regions Layer” so that you present your data well. You’ll get to set the scale and method of shading your polygons. A typical approach is to use “binned” data, and to set those bins to “quartile binning” mode. That ranges the scale for the different shades using an equation that divides the range of values. If you have outlier values, you can set your divisions by hand using “custom binning.”
- Give your map a title and include header and footer information that adequately and fully describes the data that you are visualizing.
- Publish your map.
Spring 2020