There are many different ways of measuring distance on a map.
When planning a route, it is important that you measure the distance of each stage on your route card.
There are number of different methods of measuring how long a route is on a map. You can use thread to trace the route and then measure it’s length. You can trace the path using the edge of a piece of paper and again then measure it’s length or you can use a map measurer.
Map measurers come in shapes and sizes, some are mechanical and some are digital but they all do the same job.
Silva Map Measurer
The Silva Map Measurer is an analog navigation instrument which makes the measuring of routes very easy.
This simple device is made up from two dial faces, a handle and a tracking wheel. Displayed on the dials are eight common map scales, four on each side. These scales are – 1:100k, 1:50k, 1:25k, 1:15 000, 1:750k, 1:500k, 1:400 and 1:200k. The scales allow the user to easily read the distance (km) that each stage of their route takes.
To use the device firstly ensuring the pointer is at zero (you will have to spin the wheel to reset the reading to the start point). Place the tracking wheel on to the map and, while holding the handle, push the device over the map following the line of your route.
As you move the pointer will start to rotate and marking the distance as you follow your trail. When you finish you will see the pointer indicating the distance covered.
The Silva Map Measurer is a very simple and easy to use device. However it does have some issues with maps that have been covered with plastic (waterproofing) as the wheel can’t get enough friction from the glossy surface to enable it to move fluidly. Apart from that little problem I have found it to be good addition to my route planning equipment.