| wheat {spdep} | R Documentation |
Mercer and Hall wheat yield data, based on version in Cressie (1993), p. 455.
data(wheat)
The format of the object generated by running data(wheat) is a three column data frame made available by Hongfei Li. The example section shows how to convert this to the object used in demonstrating the aple function, and is a:
Formal class 'SpatialPolygonsDataFrame' [package "sp"] with 5 slots;
the data slot is a data frame with 500 observations on the following 6 variables.
latyieldrclonlat1Cressie, N. A. C. (1993) Statistics for Spatial Data. Wiley, New York, p. 455.
Mercer, W. B. and Hall, A. D. (1911) The experimental error of field trials. Journal of Agricultural Science 4, 107-132.
## Not run:
data(wheat)
names(wheat) <- c('lon','lat','yield')
wheat$lat1 <- 69 - wheat$lat
wheat$r <- factor(wheat$lat1)
wheat$c <- factor(wheat$lon)
wheat_sp <- wheat
coordinates(wheat_sp) <- c("lon", "lat1")
wheat_spg <- wheat_sp
gridded(wheat_spg) <- TRUE
wheat_spl <- as(wheat_spg, "SpatialPolygons")
df <- as(wheat_spg, "data.frame")
row.names(df) <- sapply(slot(wheat_spl, "polygons"),
function(x) slot(x, "ID"))
wheat <- SpatialPolygonsDataFrame(wheat_spl, data=df)
## End(Not run)
wheat <- readShapeSpatial(system.file("etc/shapes/wheat.shp",
package="spdep")[1])