Scalex MapWheel

PUBLISHED : Sunday, 23 September, 2007, 12:00am
UPDATED : Sunday, 23 September, 2007, 12:00am

What is it? An effective way to measure distances on maps quickly and accurately. The MapWheel

is a robust pen-like tool fitted with a roller wheel on the tip that provides scaled measurements

of most maps. An easy-to-read screen along the side panel indicates length, count and scale factors simultaneously.

How does it work? Select the built-in scale factor to match the map to be measured, then roll the wheel between two points. An audible beeper indicates wheel movement while the length is shown instantly on the screen.

Why do I need one? At only 170 grams and 17cm long, the MapWheel is light and compact enough to be carried in a pocket by hikers, for whom every gram often counts. It is also ideal for measuring winding paths or roads on maps. The controls are simple enough for children to use and accuracy is high. The wheel is rugged enough to withstand years of use.

Tell me more: the MapWheel has 19 built-in scales and includes an auto-scale for enlarged maps or reduced or odd scales, so is suitable for use with almost any map. It measures in miles, kilometres and even nautical miles, so it can be used to provide imperial and metric measurements, which may be useful when the user is travelling to different countries. A memory function allows the storage and retrieval of measurements.

Where can I find one? The MapWheel costs GBP22.95 (HK$360) and is available online from, which can arrange delivery to Hong Kong. It comes with a one-year limited warranty and a hard plastic protective case (GBP6.95) is also available.