The Main Map
The main map starts out using the Open Street Map, and is initially centered over the continental U.S. at a zoom level of 5. To move around the map, simply hold down the left mouse button and move it in the desired direction. To zoom in or out, use the mouse's scroll wheel. To magnify a section of the map, right click and drag the magnifying glass to your desired area. To close it, left click.
Zoom and Home
The magnifying glass allows you to zoom in (+) or zoom out (-) while the home button takes you back to the middle of the US.
A cluster marker contains a number which indicates the number of park icons in that area. The marker colors indicate the number of icons in the cluster; green less than 10; yellow less than 100; red over a hundred. The zoom level controls the number of icons covered by the marker; further out will decrease the number of clusters, but the numbers will be higher and vice-versa for zooming in. Placing your mouse over a cluster will display a blue polygon showing you the area it covers and clicking on a cluster will zoom you to that area.
The scale bar helps get a sense of distances and sizes on the map and will automatically adjust as you zoom in/out on the map.
Current Position of Mouse
At the bottom of the map is a small rectangle showing the current mouse position as latitude and longitude. It also displays the current zoom level.
A small globe indicating where on the planet you are currently viewing.
The upper right corner rectangle displays the attribution for the current map being displayed.