This function obtains the indices of incidents within a specified distance around a specified point.
GeoId(x, y, distance, x.latitude = "latitude",
      x.longitude = "longitude", y.latitude = "latitude",
      y.longitude = "longitude")data frame containing the longitude and the latitude of a point.
data frame containing the longitude and the latitude of incidents.
numeric. The distance from villages in kilometers.
character.  The variable name for the latitude in x.
character.  The variable name for the longitude in x.
character.  The variable name for the latitude in y.
character.  The variable name for the longitude in y.
A vector containing the indices of y that are within
  distance kilometers around the point specified by x.  If
  there are multiple observations in x, the first row is used as
  the point.