Geocoding and Making Web Maps with Python
Table of contents
Why Python?
Its a great language! But its not the only language. Just as English, Cantonese, or Punjabi could all be used to explain systemic racism; Python, Javascirpt, or R can all be used to quantify and visualize the scale of the problem. I like python because its very flexible, fairly easy to read / write, well suited for data analysis, has lots of packages for GIS, and it’s completely free!
Packages: Python has a number of built in functions, but many of the most useful tools and functions come require us to import packages.
- Packages are pre-written blocks of code, sometimes referred to as libraries.
- They are built for addressing specific tasks: e.g. linear algebra, mapping, plotting.
Geocoding
The process of attributing coordinates (Latitude/Longitude) to descriptive locations (Street Address). With Python, we can use a variety of web based services (Google Maps, Mapbox, Open Street Maps, etc.) to perform geocoding. We’re using Mapbox today because it strikes a good balance between cost and accuracy. Google maps is arguably the best geocoding service, but it costs money :/ (5.00 USD per 1000 request). Open Street Maps is totally free, but it is error prone. Mapbox is free, up to 100,000 requests per month and gives fairly reliable results. We will be using a module called Geopy to interface with Mapbox for us.
Using Mapbox: Create a free Mapbox account. Once you have an account, you will be given an access token. Which lets you use the Mapbox service.
Web Mapping
Web mapping takes cartography beyond static maps. Today, we’ll use a Python package called follium which allows us to create dynamic, interactive web maps that can be embedded in webpages. Folium will “translate” our python commands into Javascrpt and create leaflet maps. Leaflet is a Javascript package for creating beautiful functional web maps. Follium is already installed, so we don’t have any more steps to do here!