Retrieve Environmental Data from Database

Source: R/functions.R

Queries environmental bottle cast data with temporal, depth, and variable filters. Returns a dbplyr lazy table for efficient downstream processing.

get_env(env_var, qtr, date_range, min_depth, max_depth)

Arguments

env_var

Character string of database column name for environmental variable (e.g., "t_deg_c", "salnty")

qtr

Character or numeric vector of quarters to include (1-4)

date_range

Date vector of length 2 (start date, end date)

min_depth

Numeric minimum depth in meters

max_depth

Numeric maximum depth in meters

Value

dbplyr lazy table with columns:

  • date - date of cast

  • time - time of cast (seconds since midnight)

  • dtime - datetime (computed via SQL CAST and INTERVAL)

  • depthm - depth in meters

  • lat_dec - latitude (decimal degrees)

  • lon_dec - longitude (decimal degrees)

  • qty - renamed environmental variable value

  • hex_h3res* - H3 hexagon indices at multiple resolutions

Details

The function joins cast and bottle tables, then joins with site to obtain H3 spatial indices. Only records with non-NA values for the selected variable are returned. Datetime is constructed from separate date and time fields using DuckDB SQL.

See also

prep_env_hex for spatial aggregation

prep_ts_env for temporal aggregation

Examples

if (FALSE) { # \dontrun{
# retrieve temperature data for Q1-Q2 2010-2020
df_env <- get_env(
  env_var    = "t_deg_c",
  qtr        = c(1, 2),
  date_range = as.Date(c("2010-01-01", "2020-12-31")),
  min_depth  = 0,
  max_depth  = 100
)
df_env |> collect()
} # }