North American Overlay Mapping
All the 47 smaller-scale maps have access to two Graticules, or moveable grids, that can be used to gain better positional accuracy that is available with the normal 1° Lat/Lon foreground overlay.
To toggle on and off the two Graticules, click on the small 'Grid' button, located to the right of the upper tool bar. First the 1/10th degree Graticule will come on. Another click turns that one off, and the 1/60th degree Graticule on. Another click turns them all off. When turned on, the Graticules will appear in the centre of each map. If you click the 'Grid' button, but can't see a Graticule, scroll the map back to the top left-hand corner using the scroll bars or your mouse wheel.
The Graticules can be dragged to any convenient position on the screen. To do this, turn one on as before, place your cursor over the Graticule, click-and-hold the left mouse button, then by moving the mouse, the Graticule will follow. Release the left mouse button to 'drop' the Graticule in the current position. Each Graticule has an independent position. If you turn one off, then on again, it will stay in the last position that you dragged it to. The position reverts to its default when a new map is loaded.
The Graticules allow you to better estimate position than is possible with the normal 1° Lat/Lon foreground overlay. To use them, turn on the foreground overlay, then turn on and drag one of the Graticules so that its gray grid-edges just cover the white lines of a 1° box on all 4 sides.