text w/ header font

" ## " makes it a subheading

use d3 v. 5 library of code

d3= data driven documents

call on code to read topojsons (i think)

makes notes of what attributes i want to use (fips, pop, mult_race) and then how they should appear in an array (fips #, mult race pop/ total pop = %pop mult race)

variable, not attribute? or interchangeable? i forget - come back

read as array (#) [geoid, %housing that's vacant]

WGS is spherical for the globe - not a plane

upload to observable in WGS84, and then once its here u can use observable to convert to any other projection

extracting the GeometryCollection feature collection from the json uses headers/titles for each section that the collection is nested in in document called MA_counties, it's MA_counties > objects > MA_counties (the object nested here has the GeoCollec type)

i think here is the best place to confirm that the "features"/projections is in lat/long not another format bc needs to be consistent w the used projection - GCS_WGS_1985 - used an arc tool to convert from a dif projection to this one

i don't see any lat/long actually?? I know it's in the right projection but I'm not sure how i would verify it on observable

give topo file a nickname to refer to it as in the code - "MA_counties"

defines specific set of values that were calculated in the line above as vacant_housing_pct (i think because we calculated/normalized earlier, but because it created values that weren't on the original csv they needed a name so they can be referred to later maybe) d[2] means that its calling on the third (0, 1, 2) value for each array, which is %housing vacant

naming other data GEOID, just as its called in the csv column title

naming data "county"