Iowa farmland values by county in 1925
Iowa farmland values by county in 1925
data("wallace.iowaland")A data frame with 99 observations on the following 10 variables.
countycounty factor, 99 levels
fipsFIPS code (state+county)
latlatitude
longlongitude
yieldaverage corn yield per acre (bu)
cornpercent of land in corn
grainpercent of land in small grains
untillablepercent of land untillable
fedvalland value (excluding buildings) per acre, 1925 federal census
stvalland 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
## Not run:
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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