From Text to Map

Mapbox defines geocoding as a computational process of transforming a description of a location, such as an address or place name, into geographic coordinates. The geocoding tools below will expect you to have plain text files with well-structured data. This will make it easy for a geocoding platform to read your addresses and place names and convert that descriptive location information into latitude and longitude coordinates. The mapping tools shared later in this guide will expect those coordinates to properly represent your extracted textual information as points on a map.

Formatting your coordinates

You will want your coordinates in decimals rather than degrees. Below are examples for Firestone library:

Decimals: 40.35014655510135, -74.6560466089759

Degrees: 40°21'0.52762"N, 74°39'21.76780"W

The additional text in the degrees format will not be read properly by a mapping platform.

Depending on the size of your dataset or the usability of your descriptive location information, you may want to manually add coordinates. This may be necessary for places that no longer exist or if a geocoding tool does not have adequate services for your region of study. Below are two tools for manual geocoding accompanied with a brief workflow:

Google Maps

Google Maps is a suitable solution for looking up places and other geographical objects that are currently labeled on maps. You can input addresses or search terms and then use multiple options to extract coordinates from Google Maps.

Option 1: URL coordinates

Find the coordinates in the url after you've selected a point on the map. You can see the coordinates highlighted in the url in the image below.

Option 2: Right click coordinates

Right click your selected point on the map and a popup box will appear with your point coordinates and other options. Click the point coordinates to copy them to a clipboard.

Option 3: Information box coordinates

After you select a point, a small popup box will appear at the bottom center of the map. You can access your coordinates here as well.

Wikidata

Wikidata is part of the Wikimedia commons. The data is populated by a community of users. Depending on the entry, you may find coordinate data. This may be particularly useful for historical places that no longer appear on a current map. Extracting this information manually will be more time consuming because it is formatted in degrees rather than decimals. Below is an example of a Wikidata entry with coordinate data.

Geocod.io

Geocodio: This is a geocoding platform that utilizes tabular data. The platform works with coordinates, addresses, and place names in the United States and Canada. You can either use place names and addresses to add coordinates to your data, or reverse geocode coordinates into addresses.

Geocodio requires you to create an account which includes a limited number of free “look ups” each day before you are charged. There are also features that allow you to link additional data like Census Block groups.

For a suggested workflow and other tips, please review DiScho’s Geocod.io Handout

GPS Visualizer

GPS visualizer geocoder: This tool can provide coordinates throughout the world for current places and addresses. Please see this helpful tutorial (starting with step 12) of how to use the tool.