plot.ppi: Plot a plan position indicator ('ppi')

In bioRad: Biological Analysis and Visualization of Weather Radar Data

Plot a plan position indicator (ppi)

Description

Plot a plan position indicator (PPI) generated with project_to_ppi using ggplot

Usage

## S3 method for class 'ppi'
plot(
  x,
  param,
  xlim,
  ylim,
  zlim = c(-20, 20),
  ratio = 1,
  na.value = "transparent",
  ...
)

Arguments

x	An object of class ppi.
param	The scan parameter to plot, see details below.
xlim	Range of x values to plot.
ylim	Range of y values to plot.
zlim	The range of parameter values to plot. Defaults to parameter specific limits for plotting, not full range of data.
ratio	Aspect ratio between x and y scale.
na.value	ggplot argument setting the plot color of NA values
...	Arguments passed to low level ggplot function.

Details

Available scan parameters for plotting can by printed to screen by summary(x). Commonly available parameters are:

• DBZH, DBZ: (Logged) reflectivity factor (dBZ)

• TH, T: (Logged) uncorrected reflectivity factor (dBZ)

• VRADH, VRAD: Radial velocity (m/s). Radial velocities towards the radar are negative, while radial velocities away from the radar are positive

• RHOHV: Correlation coefficient (unitless). Correlation between vertically polarized and horizontally polarized reflectivity factor

• PHIDP: Differential phase (degrees)

• ZDR: (Logged) differential reflectivity (dB) The scan parameters are named according to the OPERA data information model (ODIM), see Table 16 in the ODIM specification.

Value

No return value, side effect is a plot.

Examples

# load an example scan:
data(example_scan)

# print to screen the available scan parameters:
summary(example_scan)

# make ppi for the scan
ppi <- project_as_ppi(example_scan)

# plot the default scan parameter, which is reflectivity "DBZH":
plot(ppi)

# plot the radial velocity parameter:
plot(ppi, param = "VRADH")

# change the range of reflectivities to plot, from -10 to 10 dBZ:
plot(ppi, param = "DBZH", zlim = c(-10, 10))

# change the scale name and colour scheme, using viridis colors:
plot(ppi, param = "DBZH", zlim = c(-10, 10)) + viridis::scale_fill_viridis(name = "dBZ")

bioRad documentation built on June 17, 2025, 1:07 a.m.