This map involes converting data to GeoJSON to create basemaps. The map also shows data from D3.js library on a static map. There are data files available for download at the bottom of the page.
Q1: The city located at- -73.66333007812499, 45.4986468234261 is Montreal, Canada.
Q2: Line 64 allows an svg element added to d3. Line 72 provides the projection of the map and allows for it to be properly displayed.
Q3: 90 allows us to see the map at a specific axis projection. There are three-axis rotations that D3 supports, each offering a different view.
Q4: We would add "text-decoration: underline;" in the header where the other font specifics are defined.