Amanda Hickman

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Why Map?

We use maps to understand the data, to find a story, to tell a story. Some of my favorite examples:

California Fires (2018)

North Bay Fires (2017)

Projections, Shapes, Points, and Lines

Projections, too

Mapping Points

“Geocoding” refers to the process of identifying an individual latitude/longitude pair for an address or other location description. To actually plot a location on a map, you need the location’s latitude and longitude. 219 West 40th Street means nothing without coordinates.

Geocoding is often challenging because there aren’t great free resources for doing batch jobs or processing many addresses at once. The Geocoding Tip Sheet is a round up of good options, but often public data sources already include coordinates.

Mapping Lines

We use lines pretty rarely in intro maps, but a line is a series of two or more points connected together.

Mapping Polygons

Zipcodes, council districts, police precincts – these are all polygons. Most of your maps will be in polygons. These polygons are defined in (usually) one of two specialized file formats – a “Shapefile” or a “KML” file. The syntax of the file types varies, but they contain basically the same information – the polygon called “Bronx CB 04” is defined by this series of lat/lon pairs.

Usually your data won’t include a shapefile. If you have high school graduation rates by school district, and you want to map those, you need to find a shapefile that describes the outline of each school district, and then you need to combine that shapefile with your data, by identifying a column that the two tables have in common.

The Shapefiles Tip Sheet has some excellent resources for finding shapefiles.

Making a Map

We’re going to make our first map in Datawrapper and if that’s easy we’ll power through to Fusion Tables and Mapbox.

More Resources

Other good software options

Other good tutorial options