| LocationSet {PBSmapping} | R Documentation |
LocationSet Objects
Description
A LocationSet comprises a data frame that summarises which EventData points
(EID) lie in which PolySet polygons (PID) or
(PID, SID).
Events not located in target polygons are not reported. If an event lies on a
polygon boundary, an additional LocationSet field called Bdry is set
to TRUE. One event can also occur in multiple polygons.
PBSmapping functions that expect LocationSet's will accept properly formatted data frames in their place (see 'Details').
as.LocationSet attempts to coerce a data frame to an object with
class LocationSet.
is.LocationSet returns TRUE if its argument is of class
LocationSet.
Usage
as.LocationSet(x)
is.LocationSet(x, fullValidation = TRUE)
Arguments
x |
data frame to be coerced or tested. |
fullValidation |
Boolean value; if |
Details
A PolySet can define regional boundaries for drawing a map, and
EventData can give event points on the map. Which events occur in
which regions? Our function findPolys resolves this
problem. The output lies in a LocationSet, a data frame with three or
four columns (EID, PID, SID, Bdry), where
SID may be missing. One row in a LocationSet means that the event
EID occurs in the polygon (PID, SID). The boundary
(Bdry) field specifies whether (Bdry=T) or not
(Bdry=F) the event lies on the polygon boundary. If SID
refers to an inner polygon boundary, then EID occurs in
(PID, SID) only if Bdry=T. An event may occur in
multiple polygons. Thus, the same EID can occur in multiple
records. If an EID does not fall in any (PID, SID),
or if it falls within a hole, it does not occur in the output
LocationSet. Inserting the string "LocationSet" as the first
element of a LocationSet's class attribute alters the behaviour
of some functions, including print (if
PBSprint is TRUE) and summary.
Value
The as.LocationSet method returns an object with classes
"LocationSet" and "data.frame", in that order.
Author(s)
Nicholas M. Boers, Staff Software Engineer
Jobber, Edmonton AB
Last modified Rd: 2015-04-23