A LocationSet comprises a data frame that summarises which EventData points
EID) lie in which PolySet polygons (
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
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
TRUE if its argument is of class
data frame to be coerced or tested.
Boolean value; if
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 (
SID may be missing. One row in a LocationSet means that the event
EID occurs in the polygon (
SID). The boundary
Bdry) field specifies whether (
Bdry=T) or not
Bdry=F) the event lies on the polygon boundary. If
refers to an inner polygon boundary, then
EID occurs in
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 (
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
as.LocationSet method returns an object with classes
"data.frame", in that order.
Nicholas M. Boers, Associate Professor – Computer Science
MacEwan University, Edmonton AB
PolySet, PolyData, EventData
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