implement choropleth map / marker clustering (by city)

[emillipede]

AS A/AN: user

WHEN I: view the full extent of the LA county map

I WANT TO: see intelligible shapes / features - polygons of cities rather than individual unintelligible tree markers

Leaflet Interactive Choropleth Map tutorial

in order to accommodate more tree markers (which cover other parts of LA county - based on Matt Stiles' data repo #114) and display the map in a functional way (not an extremely long load time, users can hover and click on visible features), I'd like to use a choropleth when the map is zoomed out (similar to the screenshot of the NYC tree map below).

on hover, the polygons will display the name of the city and the tree count (according to the data in the json) - for example "Pasadena - 71,000 trees"

on click of a polygon, the map will zoom in on the selected polygon area. (at the new zoom level, the polygon will disappear from view to reveal individual tree markers)

for the boundaries, we need to follow the structure of Matt Stiles' data (grouped by city), so I've uploaded a geojson file from the LA County portal with city boundaries and population counts.

color scheme: I'd like to use a sequential color scheme for the choropleth map. I'd like to assign values (color saturation) based on public trees / city area

cityboundaries.geojson contains a field that documents each city's (and unincorporated la county) area and human population. #308 documents the need to add density and tree count fields to this json, in order to color each city by tree density.

once the density value's added to the json file, we can assign values to each city on a spectrum from most to least tree dense (number of categories + color weighting tbd).

I created a mapbox access token (pk.eyJ1IjoiZW1pbHlsaWtlc3RyZWVzIiwiYSI6ImNrYmgzbXF6dzAxa2cydG52cngwZ3A0eDEifQ.XMkB6CMXPNucpAp1qTstlg)

see NYC tree map

note: I'd prefer to use LA times' current county neighborhoods boundaries but I think that'll right now present some complications, since Matt Stiles' data are collected by city not neighborhood