Create a grid of query values for of longitude, latitude, and date.
query_grid(lon, lat, date)vector of longitudes in the grid
vector of latitudes in the grid
vector of dates in the grid
This be used as the second argument to extract() for general
'point-in-time' value extraction.
The ouput is a data frame of the grid expanded, a row for every combination of longitude, latitude, date - so can be quite large (!) so be careful with very fine resolution or long series.
lon <- c(100, 110, 120)
lat <-seq(-60, -40, by = 5)
dts <- seq(as.Date("2002-03-03"), by = "5 days", length.out = 10)
qd <- query_grid(lon = lon, lat = lat, date = dts)
## use bilinear to ensure we get an interpolate value in the grid
qd$sst <- extract(readsst, qd, method = "bilinear")
## ssha
qd$ssha <- extract(readssh, qd, ssha = TRUE, method = "bilinear")
qd$wind_mag <- extract(readwind, qd, magonly = TRUE, method = "bilinear")