subset_county_polygons: subset_county_polygons

Description Usage Arguments Value Examples

Description

Returns county polygons from: Siczewicz, Peter. U.S. Historical Counties (Generalized .001 deg) on the basis of year of interest Dataset is subset on basis of area of interest

Usage

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subset_county_polygons(year, area.column, areas)

Arguments

year

int, the year of interest to be mapped (defines historical basis for counties)

area.column

chr, defines which column to use to specify area

areas

chr, vector of codes indicating HUCs, counties, states, regions, aquifers, etc.

Value

hc.sub dataframe, a subset of county polygon data

Examples

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areas <- "Delaware" # 3 counties present day
area.column <- "STATE_TERR"
year <- 2010 
hc.sub <- subset_county_polygons(year, area.column, areas)
hc.sub$NAME

areas <- "Maine" # 16 counties present day
area.column <- "STATE_TERR"
year <- 2010 
hc.sub <- subset_county_polygons(year, area.column, areas)
hc.sub$NAME
year <- 1850 # Maine had 13 counties in 1850; Delaware 3
hc.sub <- subset_county_polygons(year, area.column, areas)
hc.sub$NAME

USGS-R/AWUDS documentation built on May 9, 2019, 6:05 p.m.