geoinside: Finds a subset of a given set of data which is inside a given...

In geo: Draw and Annotate Maps, Especially Charts of the North Atlantic

Description

Finds a subset of a given set of data which is inside or outside a given region and returns a submatrix of those values, boolean vector of indexes or index vector.

Usage

geoinside(data, reg, option = 1, col.names = c("lat", "lon"), na.rm = T,
  robust = F)

Arguments

data	a dataframe, should include vectors \$lat and \$lon, but will except other names, see col.names.
reg	The region we want to determine whether the data is inside of, should include vectors with same names as data.
option	Allows you to determine on what format you recieve the output: <s-example> option = 1: returns the submatrix of data which is inside reg. option = 2: returns the submatrix of data which is outside reg. option = 3: returns a boolean vector saying whether a given index is inside reg. option = 4: returns a boolean vector saying whether a give index is outside reg. option = 5: returns a vector of indexes to data, data[return[i],] is the i-th point in data inside reg. option = 6: returns a vector of indexes to data, data[return[i],] is the i-th point in data outside reg. </s-example>
col.names	Default col.names = c("lat","lon"), determines the names of the base vectors of the space we are viewing. May be replaced by for instance col.names = c("x","y")
na.rm	If true values where \$lat or \$lon are NA are removed. Default is false.
robust	If true a robust search is done, if false the function runs faster. Default is true. Robust = T will not work if the regions edges overlap each other, if region is sensibly defined this will not happen and robust =F should be used.

Value

Returns and output vector or matrix, see option.

Side Effects

None.

See Also

geoplot, geolocator.

Examples

## Not run:    seafishing <- geoinside(fishing,island,option=2)
   # Removes those datapoints from fishing where fishing took
   # place inside Iceland (misspells).

   grd <- list(lat=c(64,64,63,63),lon=c(-23,-22,-22,-23))
   ins.lat.64.63.lon.23.22 <- geoinside(fishing,grd,robust =T)
   # Extracts those points from fishing where fishing
   # took place inside the given box.



   #######################################################
   # Example                                             #
   #######################################################

   par(mfrow=c(2,1))
   stations<-data.frame(lat=stodvar$lat,lon=stodvar$lon)
   stations<-stations[!is.na(stations$lon),]
   stations<-stations[!is.na(stations$lat),]

   geoplot(grid=F)
   geopoints(stations,pch=".",col=25)
   title(main="Before geoinside")

   sea.stations <- geoinside(stations,island,option=2)
   # Removes those datapoints from stations where
   # measurments took place inside Iceland (misspells).

   geoplot(grid=F)
   geopoints(sea.stations,pch=".",col=25)
   title(main="After geoinside")

   #######################################################


## End(Not run)

geo documentation built on May 29, 2017, 5:36 p.m.