application.js

$(document).ready(function(){
  $(document).foundation();
  $(document).on('change.zf.tabs', '[data-active-collapse]', function () {
    window.dispatchEvent(new Event('resize'));
  });
});

gistfile1.txt

  def index
    @homes = Home.all
    @hash = Gmaps4rails.build_markers(@homes) do |home, marker|
      marker.lat home.latitude
      marker.lng home.longitude
    end

  end

location.html.erb

<div class="tabs-panel" id="geolocation">

  <div id="map" style='width: 100%; height: 300px;'></div>

  <script type="text/javascript">
    handler = Gmaps.build('Google');
    handler.buildMap({ provider: {}, internal: {id: 'map'}}, function(){
    markers = handler.addMarkers(<%=raw @hash.to_json %>);
    handler.map.centerOn(markers)
    handler.bounds.extendWith(markers);
    handler.fitMapToBounds();
    handler.getMap().setZoom(16);
    });
  </script>

</div>