Find the Polygons that Contain Events

Description

Find the polygons in a PolySet that contain events specified in EventData.

Usage

findPolys (events, polys, maxRows = 1e+05)

Arguments

Details

The resulting data frame, a LocationSet, contains the columns EID, PID, SID (if in polys), and Bdry, where an event (EID) occurs in a polygon (PID, SID) and SID does not correspond to an inner boundary. The Boolean variable Bdry indicates whether an event lies on a polygon's edge. Note that if an event lies properly outside of all the polygons, then a record with (EID, PID, SID) does not occur in the output. It may happen, however, that an event occurs in multiple polygons. Thus, the same EID can occur more than once in the output.

Value

LocationSet that links events with polygons.

See Also

combineEvents, findCells, locateEvents, locatePolys, LocationSet, makeGrid.

Examples

#--- create some EventData: a column of points at X = 0.5
events <- data.frame(EID=1:10, X=.5, Y=seq(0, 2, length=10))
events <- as.EventData(events, projection=1);
#--- create a PolySet: two squares with the second above the first
polys <- data.frame(PID=c(rep(1, 4), rep(2, 4)), POS=c(1:4, 1:4),
                    X=c(0, 1, 1, 0, 0, 1, 1, 0),
                    Y=c(0, 0, 1, 1, 1, 1, 2, 2))
polys <- as.PolySet(polys, projection=1);
#--- show a picture
plotPolys(polys, xlim=range(polys$X)+c(-0.1, 0.1),
          ylim=range(polys$Y)+c(-0.1, 0.1), projection=1);
addPoints(events, col=2);
#--- run findPolys and print the results
print(findPolys(events, polys))