spatial_means {stxplore} | R Documentation |
Computes spatial empirical means using a dataframe or a stars object
Description
This function computes spatial empirical means by latitude and longitude averaged over time. This function can take either a stars object or a dataframe. Input arguments differ for each case. The autoplot function can plot this object.
The variations are * 'spatial_means.data.frame()' if the input is a dataframe * 'spatial_means.stars()' if the input is a stars object * 'autoplot.spatialmeans()' to plot the outputs.
Usage
spatial_means(x, ...)
## S3 method for class 'data.frame'
spatial_means(x, lat_col, lon_col, t_col, z_col, ...)
## S3 method for class 'stars'
spatial_means(x, ...)
## S3 method for class 'spatialmeans'
autoplot(
object,
ylab = "Mean Value",
xlab1 = "Latitude",
xlab2 = "Longitude",
title = "Spatial Empirical Means",
...
)
Arguments
x |
A stars object or a dataframe. Arguments differ according to the input type. |
... |
Other arguments currently ignored. |
lat_col |
For dataframes: the column or the column name giving the latitude. The y coordinate can be used instead of latitude. |
lon_col |
For dataframes: the column or the column name giving the longitude. The x coordinate can be used instead of longitude. |
t_col |
For dataframes: the time column. Time must be a set of discrete integer values. |
z_col |
For dataframes: the The quantity of interest that will be plotted. Eg. temperature. |
object |
For autoplot: the output from the ‘spatial_means’ function. |
ylab |
For autoplot: the ylabel. |
xlab1 |
For autoplot: The xlabel for the first plot. |
xlab2 |
For autuoplot: The xlabel for the second plot. |
title |
The graph title. |
Value
A spatialmeans object contaiing spatial averages and the original data.
Examples
# dataframe example
data(NOAA_df_1990)
library(dplyr)
Tmax <- filter(NOAA_df_1990, # subset the data
proc == "Tmax" & # extract max temperature
month %in% 5:9 & # May to July
year == 1993) # year 1993
Tmax$t <- Tmax$julian - min(Tmax$julian) + 1 # create a new time variable starting at 1
sp_df <- spatial_means(Tmax,
lat_col = "lat",
lon_col = "lon",
t_col = "t",
z_col = "z")
autoplot(sp_df)
# stars examples
library(stars)
tif = system.file("tif/olinda_dem_utm25s.tif", package = "stars")
x <- read_stars(tif)
sp_means <- spatial_means(x)
autoplot(sp_means)