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Using the Telemeter as Coordinate Scale

Level: Basic

Instrument: Wndsn NATO-MIL Telemeter

Measuring distances on the map with the Telemeter.

The NATO MIL Telemeter has a special scale for maps at a scale of 1:25,000. This coordinate scale is used to measure or transfer rectangular coordinates from or to topographic maps using UTM, MGRS, USNG or other metric coordinate systems.

To determine a position, we first check the scale of the map; then the easting value is determined and then the northing value. The motto for this is: Get to the tree, get up the tree.

Example

We have a map at a scale of 1:25,000. Here we see how to determine the topographic values for east and north.

The easting procedure

1. We position the Telemeter horizontally on the map.
2. Then we align the 0 of the coordinate scale with the next (left) grid line.
3. We then read the value where the scale touches the target (Figure 1).

For an easting of 0.85 km or 850 m.

The northing procedure

1. We position the Telemeter vertically on the map.
2. Then we align the 0 of the coordinate scale with the next (lower) grid line.
3. We then read the value where the scale touches the target (Figure 2).

For a northing value of 0.125 km or 125 m.

The position

The final step is to combine the two values with the base values of our grid:

 422,000 E + 850 m
5022,000 N + 125 m

For a position at:

422,850 E 5022,125 N

Other scales

The 1:25,000 scale can also be used for other scales.

For maps in...

• 1:25,000 we use the measured and displayed value as is.
• 1:250,000 we multiply the displayed value by 10.
• 1:50,000 we multiply the measured value by 2.
• 1:100,000 we multiply the measured value by 4.

... as well as multiples or fractions thereof by multiplying or dividing the respective scale by 10.

See also:

• NATO-MIL Telemeter