Welcome to Methods 3, Lecture 5

This is a web page that can be viewed as slides.

→ to move forward

← to go back

Methods 3

clipping?

Ashley
Jason

project proposals due next week

project proposals

see the Final Project assignment in Canvas for links to past years' projects, expectations

source
source

joins

attribute joins

joins relate two datasets to each other

source

joins create new hybrid datasets

source
source

"I have this spreadsheet I want to map..."

you need a file with relatable geographies

usually these are IDs of some sort

and a column in each file that relates the two

open the layer properties on the layer you want to add data to

this is almost always the spatial layer (shapefile or otherwise)

go to the joins tab and add a new one

join layer: the spreadsheet you're getting data from

join field: the field to join with from the spreadsheet

target field: the field to join with from the spatial layer

in-class exercise

what is the census?

source

decennial census

American Community Survey

source
source
source
source

margin of error: higher with 1-year estimates and smaller geometries

source
source
source
source
census reporter
social explorer
NYC Population FactFinder

no matter which data you download, you'll need appropriate geographies to go with it

source

census blocks are the smallest area data is aggregated to

source
source
source
source

blocks

block groups

tracts

tracts have population between 1,200 and 8,000, optimally 4,000

source
source
source
source

NTAs are NYC-specific aggregations of census tracts

source

downloading census data

data.census.gov

joining census data

make sure you have the right boundary files

source

join on the columns that line up with each other

in this case, either

AFFGEOID and GEO.id or

GEOID and GEO.id2

in-class exercise

spatial joins

source

spatial joins

when you have layers that both have geographic features

Works best when you have:

in-class exercise