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Read a polar volume (pvol) from file

Source: R/read_pvolfile.R
read_pvolfile.Rd

Read a polar volume (pvol) from file

Usage

read_pvolfile(
  file,
  param = c("DBZH", "DBZ", "VRADH", "VRAD", "WRADH", "WRAD", "TH", "T", "RHOHV", "ZDR",
    "PHIDP", "CELL", "BIOLOGY", "WEATHER", "BACKGROUND"),
  sort = TRUE,
  lat,
  lon,
  height,
  elev_min = 0,
  elev_max = 90,
  verbose = TRUE,
  mount = dirname(file),
  local_install
)

Arguments

file

A string containing the path to a polar volume file

param

An atomic vector of character strings, containing the names of scan parameters to read. To read all scan parameters use 'all'.

sort

A logical value, when TRUE sort scans ascending by elevation.

lat

Latitude in decimal degrees of the radar position. If not specified, value stored in file is used. If specified, value stored in file is overwritten.

lon

Longitude in decimal degrees of the radar position. If not specified, value stored in file is used. If specified, value stored in file is overwritten.

height

Height of the center of the antenna in meters above sea level. If not specified, value stored in file is used. If specified, value stored in file is overwritten.

elev_min

Minimum scan elevation to read in degrees.

elev_max

Maximum scan elevation to read in degrees.

verbose

A logical value, whether to print messages (TRUE) to console.

mount

(deprecated) A character string with the mount point (a directory path) for the Docker container.

local_install

(deprecated) String with path to local vol2bird installation, to use local installation instead of Docker container

Value

An object of class pvol, which is a list containing polar scans, i.e. objects of class scan

Details

Scan parameters are named according to the OPERA data information model (ODIM), see Table 16 in the ODIM specification. 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)

Examples

# locate example volume file:
pvolfile <- system.file("extdata", "volume.h5", package = "bioRad")

# print the local path of the volume file:
pvolfile
#> [1] "/home/runner/work/_temp/Library/bioRad/extdata/volume.h5"

# load the file:
example_pvol <- read_pvolfile(pvolfile)

# print summary info for the loaded polar volume:
example_pvol
#>                Polar volume (class pvol)
#> 
#>      # scans:  3 
#>        radar:  seang 
#>       source:  WMO:02606,RAD:SE50,PLC:Angelholm,NOD:seang,ORG:82,CTY:643,CMT:Swedish radar 
#> nominal time:  2015-10-18 18:00:00 
#> 

# print summary info for the scans in the polar volume:
example_pvol$scans
#> [[1]]
#>                   Polar scan (class scan)
#> 
#>      parameters:  DBZH VRADH RHOHV ZDR PHIDP 
#> elevation angle:  0.5 deg
#>            dims:  480 bins x 360 rays
#> 
#> [[2]]
#>                   Polar scan (class scan)
#> 
#>      parameters:  DBZH VRADH RHOHV ZDR PHIDP 
#> elevation angle:  1.5 deg
#>            dims:  480 bins x 360 rays
#> 
#> [[3]]
#>                   Polar scan (class scan)
#> 
#>      parameters:  DBZH VRADH RHOHV ZDR PHIDP 
#> elevation angle:  2.5 deg
#>            dims:  480 bins x 360 rays
#> 

# copy the first scan to a new object 'scan'
scan <- example_pvol$scans[[1]]

# print summary info for the new object:
scan
#>                   Polar scan (class scan)
#> 
#>      parameters:  DBZH VRADH RHOHV ZDR PHIDP 
#> elevation angle:  0.5 deg
#>            dims:  480 bins x 360 rays