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 name | Column class |
| Event | "character" |
| DateTime | c("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" |