how to use Topo and Metro maps on Garmin eTrex Venture CX gps. you can install Garmin eTrex Venture CX with TOPO and Metro map at the same time.you can have both topo and street maps stored on the same card, but you can only view one or the other at a time, not both (hit your menu button once on the map page and select ‘map setup’ to choose which maps are turned on and off). Metro guide allows you to search for an address and mark it as …