Click check boxes to turn the map layers on or off - a request is sent to the
map server and the new map will appear.
Some layers have data tables associated with them, these will have
a symbol next to them. These layers must be turned on and highlighted
in yellow to make them active, in order to access the data tables or to pop
up boxes showing their data. See the Data/Select help pages for more details.
Some layers display only at certain map scales; these will have a instead
of a checkbox beside them.. Zoom in or Zoom out to make these layers visible.