bioRad (version 0.5.1)

map: Map a plan position indicator (ppi)

Description

Plot a ppi on a Stamen Maps, OpenStreetMap, Google Maps or Naver Map base layer map using ggmap.

Usage

map(x, ...)
# S3 method for ppi
map(
  x,
  map,
  param,
  alpha = 0.7,
  xlim,
  ylim,
  zlim = c(-20, 20),
  ratio,
  radar_size = 3,
  radar_color = "red",
  n_color = 1000,
  radar.size = 3,
  radar.color = "red",
  n.color = 1000,
  palette = NA,
  ...
)

Arguments

x

An object of class ppi.

...

Arguments passed to low level ggmap function.

map

The basemap to use, result of a call to download_basemap.

param

The scan parameter to plot.

alpha

Transparency of the data, value between 0 and 1.

xlim

Range of x values to plot (degrees longitude), as atomic vector of length 2.

ylim

Range of y values to plot (degrees latitude), as an atomic vector of length 2.

zlim

The range of values to plot.

ratio

Aspect ratio between x and y scale, by default \(1/cos(latitude radar * pi/180)\).

radar_size

Size of the symbol indicating the radar position.

radar_color

Color of the symbol indicating the radar position.

n_color

The number of colors (>=1) to be in the palette.

radar.size

Deprecated argument, use radar_size instead.

radar.color

Deprecated argument, use radar_color instead.

n.color

Deprecated argument, use n_color instead.

palette

(Optional) character vector of hexidecimal color values defining the plot color scale, e.g. output from viridis

Value

A ggmap object (a classed raster object with a bounding box attribute).

Methods (by class)

• ppi: plot a 'ppi' object on a map

Details

Available scan parameters for mapping 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.

Examples

# NOT RUN {
# load an example scan:
data(example_scan)
# make ppi's for all scan parameters in the scan
ppi <- project_as_ppi(example_scan)
# }
# NOT RUN {
# grab a basemap that matches the extent of the ppi:
# using a gray-scale basemap:
basemap <- download_basemap(ppi, maptype = "toner-lite")

# map the radial velocity scan parameter onto the basemap:
map(ppi, map = basemap, param = "VRADH")

# extend the plotting range of velocities, from -50 to 50 m/s:
map(ppi, map = basemap, param = "VRADH", zlim = c(-50, 50))

# map the reflectivity on a terrain basemap:
basemap <- download_basemap(ppi, maptype = "terrain")
map(ppi, map = basemap, param = "DBZH")

# change the color palette, e.g. Viridis colors:
map(ppi, map = basemap, param = "DBZH", palette = viridis::viridis(100), zlim=c(-10,10))

# give the data more transparency:
map(ppi, map = basemap, param = "DBZH", alpha = 0.3)

# change the appearance of the symbol indicating the radar location:
map(ppi, map = basemap, radar_size = 5, radar_color = "blue")

# crop the map:
map(ppi, map = basemap, xlim = c(12.4, 13.2), ylim = c(56, 56.5))
# }