North American Overlay Mapping

How to use the Overlay Mapping System

This user-guide is designed to be read whilst looking at the NAOMI Mapper Screen. Open both windows on your monitor, or print out this topic before opening the Global Mapper.

I will assume that you have already started the mapping system, and chosen one of the 47 small-scale maps. The 2 Overview maps use a slightly different toolbar, which I will cover later in this Help topic.

When the map loads in its default state, two things happen. The first is that the small Locator Map, which reminds you of the coverage of the larger one, displays briefly in the top left corner. The second is that the large map is displayed with the 'State' background turned on - this is indicated on the upper tool bar by a light green button. Both of these default load conditions can be changed if required - see the 'Options' page here.

Looking at the upper toolbar, lets examine the buttons in some detail. First on the left is a tiny map of North America. Clicking on this will take you straight to the Map Navigation page. Use this button when you want to display a new map, or add a map-pin at a pre-determined point on the map you are looking at, such as a city, county, user-list entry, etc.

Beneath the tiny map is the 'Locate' button. Clicking this will toggle the Locator Map on and off. The Locator Map shows the boundaries and location of the current larger map - a useful feature especially away from the coast line or other easily identifiable feature. If you wish, you can click and drag the locator map to a different part of the screen - this is handy if it is currently obscuring an important detail.

Moving to the right, the next toolbar section is the Arrow Select area. Clicking one of the arrows will load the adjacent map in that direction. If no map is available, for instance if you are already at the edge of coverage, clicking an arrow will do nothing. Note that the layout of maps is staggered to some extent, so that to move up from the current map you will need to move up-left or up-right.

In the centre of the Arrow Select area is the 'Home' button, marked with 'H'. Clicking on this will load the map that contains the location of your registered Home position, assuming of course that it is within the coverage of the North American Mapping system. When the map is loaded, the details will be mentioned in the Message Box, and a new map-pin will mark your Home position. This useful feature enables you to use your Home position as a reference point with any of the available Pin Tools.

To the right of the arrows is the Message Box. This is used to display important information throughout the mapper system, such as point load details, total entry counts, process updates, or possible error messages.

Next, is a 3x3 block of buttons that control the 9 background-overlays. These are:

  • CQ Zones, defined by color, border and number.
  • ITU Zones, defined by color, border and number.
  • Time Zones, defined by color, border and number.
  • ARRL Sections, defined by color and border. Where there is no section, such as in Mexico, Greenland, or the Bahamas, the dark-blue background color is used.
  • State/Province areas, defined by color and border.
  • County/Municipal Region areas, defined by color and border. Canada and Mexico do not have counties, so municipal regions were used instead.
  • UTM Zones, defined by color, border and number. The centre-point of each zone is also marked, as this is used as a reference point when defining a UTM Zone position.
  • Composite Satellite Photo, with no added boundaries. For more information about this layer, see here.
  • Colored relief or topographical map, with no added boundaries. For more information about this layer, see here.

Points to mention about the background layers:

  • The 'Section', 'State', and 'County' background layers have no letters that tell you which zone or region is which. This information is contained in a separate foreground overlay. This lets you compare multiple layers at once, one of the strongest features of an overlay mapping system. You may for instance wish to see where the state boundaries appear on the satellite photo, or which county is in which ARRL section.
  • The borders between countries are indicated with a thicker, 3 pixel line.
  • All backgrounds are classed as either dark or light. The color of the foreground overlays will change, depending on which background overlay is currently showing.
  • You can only have one background overlay on at a time, or none at all. There is no need to turn a background overlay off before turning another one on.
  • The name of any background overlay that is currently on is indicated by a light green button.

To the right of the background overlays are two lines of larger buttons. These control the 16 foreground overlays, which are:

  • State/Province borders and text.
  • County/Municipal Region borders and text.
  • Areacode borders and text, where available.
  • 3-digit Zipcode borders and text, where available.
  • Rivers, lakes, water feature names, island and ocean names.
  • Urbanised Areas.
  • State/Province Capitals, and Major Cities with a population over 50,000.
  • Minor Cities with population 10,000-50,000 (bold color) and <10,000 (weak color).
  • Interstates and US Routes, with equivalent roads for Canada and Mexico.
  • Railroad lines and routes.
  • Amateur Radio prefixes, and prefix borders.
  • ARRL Section borders and text.
  • IOTA code numbers, corresponding to the RSGB system.
  • Flags of the World, modified in aspect-ratio to give a constant size.
  • Grid Locator mesh, with added grid locator information.
  • 1° Latitude and Longitude mesh, with regular number idents.

Points to mention about the foreground layers:

  • You can turn as many foreground layers at one time as you want, to compare how the data interrelates.
  • Choose the stacking order for best clarity.
  • The layer that is currently on top is indicated by the colored bar between the two rows of foreground buttons.
  • To bring a buried layer to the top, simply turn it off then on again.

Finally, to the right of the foreground buttons, there are a small block of 6 other buttons that add extra facilities to the map currently on display:

  • The 'Help' button opens a new window containing the Help and Information Guide, which you are reading right now.
  • The 'APRS' button opens the APRS interface box, which will overlay live position icons, track-lines, and breadcrumbs for all APRS stations in the FindU database onto the current map. For more information about this facility, see here.
  • The 'Tools' button opens a menu-box that provides access to the Table Viewer, and a wide variety of other useful Tools. Each of these tools has their own Help page - see Help Contents or Index for further details.
  • The 'Grid' button toggles the two Graticules (decimal or seconds) on and off. Click to alternate which one is on - each will remember its current position. Click and Drag a graticule to move it around the screen - they are especially useful when you have turned the main 1° Lat/Lon overlay on.
  • The 'Scale' button toggles the Scale-Bar on and off. Click and Drag to move it around the screen. The Scale-Bar provides only a rough idea of horizontal distance; its accuracy diminishes towards the map-edges. For a more accurate measure of distance, add two pins to the map and use the 'Pin Distance' tool - details here.
  • The 'Time' button toggles the Time Display box on and off. Use it to find the current UTC time, or the time in any of the 8 North American time zones. For more information about this facility, see here.

Whilst a map is displayed, a variety of very accurate positional, distance, and bearing information relating to the current cursor position and your registered home position is displayed on the status bar, at the bottom of your browser screen. The units and format displayed can all be changed to one of a variety of possibilities, using the 'Options' menu. For more information about this, visit the Status Bar help-page, by clicking here.

Clicking on the map itself will add a map-pin, which can be used to reference that position against other pins, and a large number of other pre-programmed positions. Click the pin itself if you want to remove it. See the 'All about Pins' page here for a full explanation of map-pins, and how to use them.

The Overview maps, mentioned above, have a few overlays that are different from the other 47 small-scale maps. The background overlays have one change: instead of the county background there is an overlay called 'Lights', which shows an actual satellite photo of the North American continent at night. The foreground overlays have two changes: instead of the Zipcode borders, there is an overlay showing the distribution of US hams, created from the latest callsign details on the FCC database. Also, instead of the Minor City overlay, there is an overlay showing a 5° Latitude and Longitude mesh.

The Overview maps also have two tools missing: the Graticules and the Scale Bar. The Graticules would be too small to be of any use; the Scale Bar would not be useful on a map of this scale due to inaccuraccies over the wide range of latitudes covered.