North American Overlay Mapping
Click 'Tools' > 'Pin Rings' to access this tool. Its function is to draw a range ring, and will use any one of the currently-selected Map-Pins on the current map as its centre-point.
When the 'Pin Rings' tool is started, it tells you how many Map-Pins are currently selected, and displays a number of colored spots to represent each one. To draw a range ring, first enter the required range in the 'Range Distance' box, then simply click the required colored spot.
You can also choose various options for the rings that you draw:
- Intermediate Rings: on or off
- Intermediate Ring Spacing: choice of 4 spacings
- Color of Lines: choice of 8 colors
- Width of Lines: choice of 3 widths
- Labels: on or off
Important: Rings are drawn by adding layers for each rectangle that forms a circle. Thus, even on a fast computer, intermediate rings can take up to 30 seconds to draw.
The intermediate ring before the main ring is not drawn, to avoid overcrowding. Thus, if you draw a ring at 126 miles, with intermediate rings every 25 miles, rings will be drawn at 25m, 50m, 75m, 100m, 126m. If you wish to see the 125m ring, add it separately, with labels off.
Some people may wonder why the rings are oval in shape, and not circular. This is because of the projection used, where the actual width of a 1° square in miles will vary in size as you move from the equator towards the poles. For further information, see the Projection page.
When the ring has been drawn, three additional buttons control how the graphics are displayed:
- Clear: will delete these graphics
- Hide: will hide these graphics
- Show: will show these graphics
If no lines have been drawn, these buttons will appear to do nothing, apart from giving their normal audio feedback. To turn audio feedback on or off, use the 'Options' tool.
Note: When a new map is loaded, or when you visit the Calculation Page or Table Viewer, all graphics are discarded.