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

## Description

Simple function to plot a velocities vector field.

## Usage

 `1` ```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

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27``` ```## Not run: metU <- importADSOBIN('/path/to/meteofile', variable = 'U', slice=2, k = 1000, verbose = TRUE) metU <- as.data.frame(metU) metU <- metU %>% mutate(u = z, z = NULL) metV <- importADSOBIN('/path/to/meteofile', 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. 30, 2021, 1:08 a.m.