North American Overlay Mapping

The Map Navigation Page

The Map Navigation page is where most of the decisions are made as to which map to load, so its worth being familiar with its different options. That said, it was designed to be as straight-forward as possible, and easy to use with out any technical knowledge, so hopefully this Help Page will not tell you anything you couldn't work out for yourself !

The easiest way to load a map is to simply click somewhere on the small map that dominates the Map Navigation page. As you move your mouse over the map, a red frame follows your cursor, showing the borders of the map that will load if you click at that point. Just like the maps, the borders of the frame for one map overlap the borders of the next one, so no point is at the edge of two maps.

The ocean areas aren't covered by a moving frame, but you can still get a map that covers these by choosing one of the two large scale 'Overview' maps. You can load these by clicking the words 'Overview - West' or 'Overview - East' along the bottom of the map. The two Overview maps include all the area covered by the smaller scale maps, plus an extended coverage to 73.7N and 180W, which takes in all of the Aleutians, Alaska, and the continental areas of Yukon Territory, Northwest Territories, and Nunavut.

The 'Select Map by Name' box gives you an alternate way of loading a map; one that shows the real power of the NAOMI interface. 138 different lists and sub-lists provide a large variety of ways to quickly load not just the map of the area that you are interested in, but also to have the exact position on that map marked with a map-pin. Select the category that you want in the upper list-select box first; when you have done that, the corresponding list is automatically loaded into the lower list-select box. Choose the value that you want, click the nearby 'Go' button, and the correct map is loaded, a new map-pin marks the point of interest, and the point's Type, Location Name, and Position are all mentioned in the Message Box, on the upper toolbar.

An exception to this is for the two list types 'Smaller Cities', and 'Counties'. When you choose these, a state/province list is provided, but when you click the 'Go' button, a new box opens, letting you choose the exact city or county for that area. Note that some of these lists, for instance the city lists of California, Illinois, Pennsylvania, Quebec, and Texas, have long lists that take a while to format on a slower computer: please be patient whilst they load.

If you know the exact position that you want to see a map of, you can enter that directly into the entry areas of the 'Select Map by Position' box. The two entry areas, one for Longitude (i.e. running East to West) and one for Latitude (i.e. running North to South) will take either an entry in the decimal format, or an entry using the older system of degrees, minutes and seconds, where a degree is split into 60 equal seconds, and a second is split into 60 equal minutes.

To enter a decimal position, use the format '123.45', where '123' are the degrees, and '45' are the decimal divisions, if any, with a period separating the two. For whole degrees, just enter '123'. (Note that only 2 decimal values are processed; anything else, such as '123.456789' will have the extra values ignored. As one pixel on a map is roughly equivalent to 0.01 degrees at this scale, any greater precision is pointless to implement.)

If you wish to enter a position using degrees, minutes and seconds, you should space the values with the letters 'dms' as follows: '111d22m33s'. In this example, '111' are the degrees, '22' are the minutes, and '33' are the seconds. If you just have a minute value but no seconds, you can enter either '111d22ms' or '111d22m00s' or '111d22m'.

Note that for both decimal and dms entry, the quadrant values normally associated with a position (NSEW) are not used. 'West' and 'North' are assumed for whatever value you enter - anything else is outside the boundaries of the North American Overlay Mapping system.

You can also load a map and have the position indicated if you know the Grid Locator, also called the Maidenhead Grid Locator. (For more information about the Grid Locator system, click Here). The grid locator can be entered in two levels of precision: 4 characters (i.e. DM07) which will describe the centre of a square one degree of latitude high by two degrees of longitude wide, or 6 characters (i.e. DM07aa) which will describe the centre of a square 2.5 minutes of latitude high by 5 minutes of longitude wide, and define a position to within better than 5.6 nautical miles anywhere on the surface of the Earth.

You can enter a grid locator in any of the following formats: 'DM07aa', 'DM07AA', 'dm07aa', or 'dm07AA'. After entering the value, click the nearby 'Go' button, and the correct map is loaded, with a new map-pin marking the grid-locator point, and the point's Type, grid-locator Value, and Position all mentioned in the Message Box, on the upper toolbar.

The toolbar associated with the Map Navigation page has limited functions compared to the toolbar loaded with the maps, but there are still some useful buttons available. Click the 'H' button, to the left of the toolbar, and the map will be loaded that contains your registered home position. The exact position will be indicated by a map-pin as before, enabling you to use the point as reference to any other. The 'Help', 'Tools', and 'Time' buttons also operate as normal. You can find more about their function in the relevant sections of the Help and Information guide.