documented docs/

Author: schloerke

docs/shiny.html

@@ -410,6 +410,7 @@ <h4>Map events</h4>
 <p><code>input$<em>MAPID</em>_click</code> is an event that is sent when the map background or basemap is clicked. The value is a list with <code>lat</code> and <code>lng</code>.</p>
 <p><code>input$<em>MAPID</em>_bounds</code> provides the latitude/longitude bounds of the currently visible map area; the value is a <code>list()</code> that has named elements <code>north</code>, <code>east</code>, <code>south</code>, and <code>west</code>.</p>
 <p><code>input$<em>MAPID</em>_zoom</code> is an integer that indicates the <a href="http://wiki.openstreetmap.org/wiki/Zoom_levels">zoom level</a>.</p>
+<p><code>input$<em>MAPID</em>_center</code> provides the latitude/longtitude of the center of the currently visible map area; the value is a <code>list()</code> that has named elements <code>lat</code> and <code>lng</code>.</p>
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