layer at which raster maps are imported. If
is NULL, maps ara no-zlayer distributed and
zoo must be returend by
pointer.to.maps.xy.time
timerange
two-elememts vector containing the time
range at which geotop maps are imported
time
vector of time instants at which geotop maps
are imported
rows
rows of zoo correspondig to the geotop
maps that are imported. By default all rows of zoo
are considered. It is calculated by time or
timerange if they are not set as NULL.