EventData: EventData Objects

In PBSmapping: Mapping Fisheries Data and Spatial Analysis Tools

EventData Objects

Description

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.

Usage

as.EventData(x, projection = NULL, zone = NULL)
is.EventData(x, fullValidation = TRUE)

Arguments

x	data frame to be coerced or tested.
projection	optional projection attribute to add to EventData, possibly overwriting an existing attribute.
zone	optional zone attribute to add to EventData, possibly overwriting an existing attribute.
fullValidation	Boolean value; if TRUE, fully test x.

Details

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.

Value

The as.EventData method returns an object with classes "EventData" and "data.frame", in that order.

Author(s)

Nicholas M. Boers, Staff Software Engineer
Jobber, Edmonton AB
Last modified Rd: 2015-04-23

See Also

PolySet, PolyData, LocationSet

PBSmapping documentation built on Sept. 30, 2024, 9:21 a.m.