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Retrieve ERA5 variable along edge

Source: R/edge_add_wind.R
edge_add_wind.Rd

Reads the NetCDF files and extracts the variable requested along each flight defined by the edges.

  • Time: linear interpolation using the resolution requested with rounding_interval

  • Space: nearest neighbour interpolation by default, or bi-linear with pracma::interp2 if interp_spatial_linear=TRUE. Note: spatial interpolation is limited to 0.1° for computational reasons.

  • Pressure/altitude: linear interpolation using the exact pressure values

Usage

edge_add_wind(
  graph,
  edge_s,
  edge_t,
  pressure = NULL,
  variable = c("u", "v"),
  rounding_interval = 60,
  interp_spatial_linear = FALSE,
  return_averaged_variable = FALSE,
  file = function(stap_id, tag_id) {
    
    glue::glue("./data/wind/{tag_id}/{tag_id}_{stap_id}.nc")
 },
  quiet = FALSE
)

Arguments

graph

either a tag or a graph GeoPressureR object.

edge_s

a index of the source node of the edge. Either a vector with 3D index or a matrix of 3 columns, one for each dimension.

edge_t

a index of the target node of the edge. Either a vector with 3D index or a matrix of 3 columns, one for each dimension.

pressure

pressure measurement of the associated tag data used to estimate the pressure level (i.e., altitude) of the bird during the flights. This data.frame needs to contain date as POSIXt and value in hPa. If not provided, uses graph$pressure, assuming that argument graph is a GeoPressureR tag object.

variable

list of the variables to extract from the ERA5 pressure level using the shortName notation: "u", "v", "t", "cc", "r", "w", "ciwc", "clwc", "q", "cswc", "d", "z", "o3", "pv", "vo".

rounding_interval

temporal resolution on which to query the variable (min). Default is to match ERA5 native resolution (1hr).

interp_spatial_linear

logical to interpolate the variable linearly over space, if FALSE takes the nearest neighbour. ERA5 native resolution is 0.25°

return_averaged_variable

logical to return the variable for each timestep or average for the entire flight.

file

absolute or relative path of the ERA5 wind data file to be downloaded. Function taking as arguments (1) the stationary period identifier and (2) the tag_id.

quiet

logical to hide messages about the progress

Value

If return_averaged_variable = TRUE, returns a data.frame with one row per edge and columns:

  • stap_s id of the source/origin stationary period

  • stap_t id of the target/destination stationary period

  • s node id of the source (same as/similar to edge_s)

  • t node id of the target (same as/similar to edge_t)

  • lat_s latitude of the source

  • lat_t latitude of the target

  • lon_s longitude of the source

  • lon_t longitude of the target

  • start start datetime of the flight

  • end end datetime of the flight

  • duration flight duration

  • n number of flight

  • distance distance of the flight

  • bearing bearing of the flight

  • gs groundspeed

  • ws windspeed (if graph provided)

If return_averaged_variable = FALSE, returns a data.frame with one row per time step and edge, and columns:

  • edge_id edge index

  • val value of the variable at each time step

  • pressure pressure at each time step

  • date datetime of each time step

  • w weight for averaging

  • var variable name

  • lat latitude at each time step

  • lon longitude at each time step

See also

GeoPressureManual