Welcome to Methods 3, Lecture 4
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Methods 3
(review)
Choropleth?
source
Louisiana Loses Its Boot
"Using publicly available data, [we] created a map on which areas that commonly appear as land on government issued maps—woody wetlands, emergent herbaceous wetlands and barren land—were re-categorized to appear as water."
the modifiable areal unit problem
source
"One-third of all homes with a Flint ZIP code lie outside the city. Thus, the state’s numbers for Flint were watered down by an additional 50 percent of addresses that weren’t in the city and weren’t using Flint water."
source
Callan
Matt
duplicating layers
you can copy and paste styles
you can save a layer with its style
basic statistics
Start thinking about methodology
select by location
you should almost never make choropleths with just counts
think about ways to normalize your data
this make the data comparable across regions
a GIS will let you:
- visualize map data
- create and edit map data
- overlay map data
- analyze map data
Geoprocessing
buffers
buffers
make a "buffer" around features
well, why?
you can make negative buffers
clipping
overlay operations
Intersect
Union
usually you'll use geoprocessing functions in a chain
keep track of these as you work!
joins
attribute joins
joins relate two datasets to each other
joins create new hybrid datasets
source
"I have this spreadsheet I want to map..."
you need a file with relatable geographies
and a column in each file that relates the two
...continued next week