combineEvents {PBSmapping}R Documentation

Combine Measurements of Events

Description

Combine measurements associated with events that occur in the same polygon.

Usage

combineEvents (events, locs, FUN, ..., bdryOK = TRUE)

Arguments

events

EventData with at least four columns (EID, X, Y, Z).

locs

LocationSet usually resulting from a call to findPolys.

FUN

a function that produces a scalar from a vector (e.g., mean, sum).

...

optional arguments for FUN.

bdryOK

Boolean value; if TRUE, include boundary points.

Details

This function combines measurements associated with events that occur in the same polygon. Each event (EID) has a corresponding measurement Z. The locs data frame (usually output from findPolys) places events within polygons. Thus, each polygon (PID, SID) determines a set of events within it, and a corresponding vector of measurements Zv. The function returns FUN(Zv), a summary of measurements within each polygon.

Value

PolyData with columns PID, SID (if in locs), and Z.

See Also

findCells, findPolys, locateEvents, locatePolys, makeGrid, makeProps.

Examples

#--- create an EventData data frame: let each event have Z = 1
events <- data.frame(EID=1:10, X=1:10, Y=1:10, Z=rep(1, 10))
#--- example output from findPolys where 1 event occurred in the first
#--- polygon, 3 in the second, and 6 in the third
locs <- data.frame(EID=1:10, PID=c(rep(1, 1), rep(2, 3), rep(3, 6)),
                   Bdry=rep(0, 10))
#--- sum the Z column of the events in each polygon, and print the result
print(combineEvents(events=events, locs=locs, FUN=sum))

[Package PBSmapping version 2.61.9 Index]