Find GeoJSON Boundary Files

You may be searching for geographic boundary files in GeoJSON format to create a customized map, such as a choropleth map in Datawrapper as described in Chapter 8, or when using a Leaflet map code code template as described in Chapter 13, which both allow you to upload your own GeoJSON files. Since GeoJSON is an open data standard, you may find them in the open data repositories listed in Chapter 4.

Another way to find and download GeoJSON files is Gimme Geodata, a clever tool developed by Hans Hack, which provides quick access to multiple layers of OpenStreetMap boundary files. When you open the tool, search for a location and click a specific point on the map. The tool displays the names and outlines of different geographic boundaries around that point that have been uploaded into OpenStreetMap, which you can select and download in GeoJSON format. For example, when you search and click on Toronto Centre, the tool displays several neighborhood-level boundaries, the Old Toronto city boundary, the present-day Toronto city boundary, and regional and provincial boundaries, as shown in Figure 14.6. Read more details about each layer to evaluate its accuracy, then select any to download in GeoJSON format. The tool also includes an editor (the scissors symbol) to remove water areas, such as Lake Ontario, from the boundary file. When using any type of data that you downloaded from OpenStreetMap, be sure to credit the source in your final product like this: © OpenStreetMap contributors.

Use the Gimme Geodata tool to select a point and download surrounding geographic boundaries from Open Street Map.

Figure 14.6: Use the Gimme Geodata tool to select a point and download surrounding geographic boundaries from Open Street Map.