selpos: Geographical point selection.

Description

Select geographical data points by arbitrary criterion.

Usage

selpos(lat, lon = NULL, ind)

Arguments

lat

Latitude of points or list containing lat,lon.

lon

Longitude of data points. If missing, this must be part of the lat argument.

ind

Selection criterion.

Value

Returns list with elements lat,lon which satisfy the criterion.

Details

The normal way of working with geographical data is to store positions as a list with names lat and lon. This is easier for most applications, except selection of subsets, where it is essential to access individual elements. The purpose of this routine is merely to ease the selection process.

Examples

Run this code

## Not run: 
#              subs<-selpos(pos,,z>6)# Select positions where z>6
# 
#        The Function is trivially defined as
#        function(lat, lon = NULL, ind)
#        {
#                       if(is.null(lon)) {
#                            lon <- lat$lon
#                            lat <- lat$lat
#                       }
#                       lat <- lat[ind]
#                       lon <- lon[ind]
#                       return(lat, lon)
#        }
# ## End(Not run)