An EventData object comprises a data frame with at least three fields named
EID
, X
, and Y
; each row specifies an event that occurs
at a specific point.
PBSmapping functions that expect EventData will accept properly formatted data frames in their place (see 'Details').
as.EventData
attempts to coerce a data frame to an object with
class EventData.
is.EventData
returns TRUE
if its argument is of class
EventData.
as.EventData(x, projection = NULL, zone = NULL)
is.EventData(x, fullValidation = TRUE)
data frame to be coerced or tested.
optional projection
attribute to add to
EventData, possibly overwriting an existing attribute.
optional zone
attribute to add to EventData,
possibly overwriting an existing attribute.
Boolean value; if TRUE
, fully test
x
.
The as.EventData
method returns an object with classes
"EventData"
and "data.frame"
, in that order.
Conceptually, an EventData object describes events (EID) that take place at specific points (X,Y) in two-dimensional space. Additional fields can specify measurements associated with these events. In a fishery context, EventData could describe fishing events associated with trawl tows, based on the fields:
EID
- fishing event (tow) identification number;
X
, Y
- fishing location;
Duration
- length of time for the tow;
Depth
- average depth of the tow;
Catch
- biomass captured.
Like PolyData, EventData can have attributes projection
and zone
, which may be absent. Inserting the string
"EventData"
as the class attribute's first element alters the
behaviour of some functions, including print
(if
PBSprint
is TRUE
) and summary
.