d3-slippy: Slippy Projection

Born out of the odd frustration at working with tile units with d3.tile and geographic units, where I often end up duplicating coordinate systems (example), despite not really needing to actually know what the tile units are.

This is a quick experiment, but I hope to work on it moving forwards.

In my mind this experimental module is easier to work with when combined with geographic data than d3-tile, but I might not be familiar enough with d3-tile to use it effectively.

This block does not use d3.tile, though it was a very useful reference.

This block uses ESRI's World Ocean Basemap Tiles (c) Esri - Source: GEBCO, NOAA, CHS, OSU, UNH, CSUMB, National Geographic, DeLorme, NAVTEQ, and Esri.

Basic Overview

Essentially d3.slippy() holds a d3.geoMercator() projection and based on the projection's property, looks up which tiles should be displayed given a certain pixel extent of the svg.

See github for additional information.