wallace.iowaland | R Documentation |
Iowa farmland values by county in 1925
data("wallace.iowaland")
A data frame with 99 observations on the following 10 variables.
county
county factor, 99 levels
fips
FIPS code (state+county)
lat
latitude
long
longitude
yield
average corn yield per acre (bu)
corn
percent of land in corn
grain
percent of land in small grains
untillable
percent of land untillable
fedval
land value (excluding buildings) per acre, 1925 federal census
stval
land value (excluding buildings) per acre, 1925 state census
None.
H.A. Wallace (1926). Comparative Farm-Land Values in Iowa. The Journal of Land & Public Utility Economics, 2, 385-392. Page 387-388. https://doi.org/10.2307/3138610
Larry Winner. Spatial Data Analysis. https://www.stat.ufl.edu/~winner/data/iowaland.txt
library(agridat)
data(wallace.iowaland)
dat <- wallace.iowaland
# Interesting trends involving latitude
libs(lattice)
splom(~dat[,-c(1:2)], type=c('p','smooth'), lwd=2, main="wallace.iowaland")
# Means. Similar to Wallace table 1
apply(dat[, c('yield','corn','grain','untillable','fedval')], 2, mean)
# Correlations. Similar to Wallace table 2
round(cor(dat[, c('yield','corn','grain','untillable','fedval')]),2)
m1 <- lm(fedval ~ yield + corn + grain + untillable, dat)
summary(m1) # estimates similar to Wallace, top of p. 389
# Choropleth map
libs(maps)
data(county.fips)
dat <- transform(dat, polnm = paste0('iowa,',county)) # polnm example: iowa,adair
libs("latticeExtra") # for mapplot
redblue <- colorRampPalette(c("firebrick", "lightgray", "#375997"))
mapplot(polnm~fedval , data=dat, colramp=redblue,
main="wallace.iowaland - Federal land values",
xlab="Land value, dollars per acre",
scales=list(draw=FALSE),
map=map('county', 'iowa', plot=FALSE,
fill=TRUE, projection="mercator"))
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