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The das_df class is a subclass of data.frame, created to provide a concise and robust way to ensure that the input to downstream DAS processing functions, such as das_sight, adheres to certain requirements. Specifically, objects of class das_df are data frames with specific column names and classes, as detailed in the 'Properties of das_df' section. Objects of class das_df are created by das_process or as_das_df, and are intended to be passed directly to DAS processing functions such as das_sight.

Subsetting, say for a specific date or cruise number, or otherwise altering an object of class das_df will cause the object to drop its das_df class attribute. If this object is then passed to a DAS processing function such as das_sight, the function will try to coerce the object to a das_df object.

Properties of das_df objects

All values in the Event column must not be NA.

Objects of class das_df have a class attribute of c("das_df", "data.frame"). In addition, they must have the following column names and classes:

Column nameColumn class
Event"character"
DateTimec("POSIXct", "POSIXt")
Lat"numeric"
Lon"numeric"
OnEffort"logical"
Cruise"numeric"
Mode"character"
EffType"character"
Course"numeric"
SpdKt"numeric"
Bft"numeric"
SwellHght"numeric"
WindSpdKt"numeric"
RainFog"numeric"
HorizSun"numeric"
VertSun"numeric"
Glare"logical"
Vis"numeric"
ObsL"character"
Rec"character"
ObsR"character"
ObsInd"character"
Data1"character"
Data2"character"
Data3"character"
Data4"character"
Data5"character"
Data6"character"
Data7"character"
Data8"character"
Data9"character"
Data10"character"
Data11"character"
Data12"character"
EffortDot"logical"
EventNum"integer"
file_das"character"
line_num"integer"

See also