# vectorField: Vector field plot In simulariatools: Simularia Tools for the Analysis of Air Pollution Data

 vectorField R Documentation

## Vector field plot

### Description

Simple function to plot a velocities vector field.

### Usage

``````vectorField(data, scale = 1, everyx = 1, everyy = 1, size = 0.25)
``````

### Arguments

 `data` A dataframe containing data to be plotted in the form of: (x, y, u, v). `scale` length factor of vector components `everyx` keep one out of every everyx values, along x direction. `everyy` keep one out of every everyy values, along y direction. `size` arrow size.

### Details

This function plots a vector field given a data.frame with coordinates (x, y) and corresponding velocity components (u, v). Vectors are coloured by magnitude (speed). The coordinates are assumed to be on a regular rectangular domain in UTM reference system.

This function is heavily inspired by snippets of code in R Graphics Cookbook by Winston Chang (https://r-graphics.org/index.html).

### Value

A `ggplot2` plot.

### Examples

``````## Not run:
variable = 'U',
slice=2,
k = 1000,
verbose = TRUE)
metU <- as.data.frame(metU)
metU <- metU %>%
mutate(u = z, z = NULL)

variable = 'V',
slice=2,
k = 1000,
verbose = TRUE)
metV <- as.data.frame(metV)
metV <- metV %>%
mutate(v = z, z = NULL)

met <- merge(metU, metV, by = c("x", "y"))

vectorField(met, everyx = 2, everyy = 2, scalex = 10, scaley = 10) +
coord_fixed(ratio = 1, xlim = c(0, 1000), ylim = c(0, 1000)) +
scale_color_viridis_c()

## End(Not run)
``````

simulariatools documentation built on Nov. 8, 2023, 5:07 p.m.