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.
lat
yield
r
c
lon
lat1
Cressie, 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])