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Read Campbell CR23X .dat files using .dld column definitions

read_old_campbell_dat.Rd

Parses the headerless comma-separated data files produced by Campbell Scientific CR23X dataloggers, using the accompanying Final Storage Label (.dld) file to assign column names. Multiple output tables with different sampling intervals coexist in the same .dat file; each is returned as a separate element of a named list.

Usage

read_old_campbell_dat(fname_dat, fname_dld, year = NULL, table_id = NULL)

Arguments

fname_dat

Path to the Campbell .dat file.

fname_dld

Path to the corresponding .dld (Final Storage Label) file.

year

Integer. Calendar year for the first data row. If NULL (default) it is inferred from the filename as described above.

table_id

Integer or character. If supplied, return only the data.table for this table identifier. Otherwise a named list of data.tables is returned, one per table found in the file.

Value

A named list of data.tables (names are the table identifiers as they appear in column 1 of the .dat file), each with a leading TIMESTAMP (POSIXct, UTC) column followed by the measurement variables named from the .dld. A single data.table is returned when table_id is specified.

Details

The two _RTM (Real-Time) columns in each output-table definition are treated as timestamp components: the first is day-of-year (1–366) and the second is time of day in HHMM format (e.g. 1015 = 10:15). A TIMESTAMP (POSIXct, UTC) column is synthesised from these plus the year. Year-rollover within a file (day-of-year decreasing from ~365 to 1) is detected automatically.

When year is not supplied it is inferred from the filename pattern _YYYY_MM_DD: if the first data row's day-of-year is > 300 and the filename month is <= 3, the year is decremented by one (files downloaded in early January commonly contain data from late December of the prior year).

Output-table definitions are matched to data rows first by the table identifier in column 1, then by column count as a fallback (used when the logger program has been revised and the table number changed since the .dld was generated).

Examples

if (FALSE) { # \dontrun{
tables <- read_old_campbell_dat(
  pkg_extdata("UK-WHM/current/whim_met_2026_01_05.dat"),
  pkg_extdata("UK-WHM/current/Whim23X260609.dld")
)
dt_15min <- tables[["120"]] # 15-minute output table
dt_1min <- tables[["227"]] # 1-minute output table
} # }