query_grid: Create a query grid

In AustralianAntarcticDivision/raadtools: Tools for Synoptic Environmental Spatial Data

Create a query grid

Description

Create a grid of query values for of longitude, latitude, and date.

Usage

query_grid(lon, lat, date)

Arguments

lon	vector of longitudes in the grid
lat	vector of latitudes in the grid
date	vector of dates in the grid

Details

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.

Examples

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") 

AustralianAntarcticDivision/raadtools documentation built on Nov. 14, 2024, 4:27 p.m.