quiver {satin}

Vectors of ocean currents velocities

Description

Plot vectors of ocean current velocities of varying size or color for Copernicus data.

Usage

quiver(u, v, period = 1, depth = 1, xlim = NULL, ylim = NULL, scale = 1, 
       length = 0.05, colarrow = NULL, scheme = "default", ra.pos = NULL, 
       ra.speed = NULL, map = NULL, map.col = "grey", map.outline = "black", 
       colbar = FALSE, main = NULL, main.pos = "topright", add2map = FALSE, ...) 

Arguments

u

a satin object with eastward ocean current velocities (in m/s).

v

a satin object with northward ocean current velocities (in m/s).

period

an integer referring to the image number to plot.

depth

an integer referring to a depth level.

xlim

minimum and maximum longitude values for the map.

ylim

minimum and maximum latitude values for the map.

scale

this argument controls the arrow length.

length

this value controls the size of the arrow head.

colarrow

color(s) for the arrows; see details.

scheme

color scheme for the arrows. Either: "default" or a vector of valid color names.

ra.pos

position (lon, lat) for a reference arrow.

ra.speed

speed (in m/s) of the reference arrow. The mean is used by default.

map

a user defined map of class "SpatialPolygons".

map.col

color for the map.

map.outline

color for the map outline.

colbar

logical. If TRUE a color bar is added to the plot.

main

title for the map, defaults to the corresponding selected image period.

main.pos

position for the title: "topright", "topleft", "bottomright" or "bottomleft".

add2map

a logical value. If FALSE an entire new plot is created. If TRUE ocean current velocity arrows are added to an existing plot.

...

further arguments to pass to arrows.

Details

Usage and behavior of this function closely resembles that of plot.satin. It differs in that two different satin objects are needed, one for each component of ocean current velocities. Also, the ocean current vectors can be overlayed to an existing plot of another variable, as the temperature, for instance.

Value

A map of the ocean current velocities is produced.

Author(s)

Héctor Villalobos

Examples

if(interactive()){
# import copernicus data with potential temperatures and ocean current velocities
oc <- read.cmems("global-reanalysis-phy-001-030-daily_1560792767602_GC_2013-14.nc")

# Default plot
quiver(u = oc$uo, v = oc$vo)

# Using default colors for the arrows, color bar and reference arrow
quiver(u = oc$uo, v = oc$vo, colarrow = TRUE, colbar = TRUE,
       ra.pos = c(-108, 30))

# Adding custom map and colors, and plotting another period and depth level
quiver(u = oc$uo, v = oc$vo, image = 4, depth = 10, colbar = TRUE,
       colarrow = TRUE, scheme = c("mediumblue", "lightcyan", "red"), 
       map = dmap, ra.pos = c(-108, 30), ra.speed = 0.2)


# Overlay arrows to an existing plot of the potential temperature
plot(oc$thetao, map = dmap, xlim = c(-112, -108), ylim = c(24, 28), 
     colbar = FALSE)
quiver(u = oc$uo, v = oc$vo, colarrow = TRUE, ra.pos = c(-108.5, 27), 
       ra.speed = 0.15, main = "", length=0.02, scale = 0.7, add2map = TRUE)	   
}