I read in one of the previous Protea Atlas newsletters that you regard location data obtained from Global Positioning System (GPS) with some suspicion. I am motivating for the Mountain Club to buy a GPS, partly to contribute to Protea Atlassing. If you do not regard GPS data as accurate enough, obviously we will have to think twice before investing in one.
Reuben Heydenrych, Pretoria

A GPS is a tool. Like any other tool it works well under certain conditions, and is useless under others. Used properly it will give you very good results, used carelessly it can kill. Like all tools, relying exclusively on a single tool is stupid. So:

Please use your GPS. But, always take a map with you. Check that your GPS readings make sense with regard to your map. If in doubt, believe the map. Regularly (at the very minimum, every month) calibrate your GPS with known waypoints. Ignore GPS altitudes, if they are within 100m of your map altitude. If more, suspect the co-ordinate data as well. This is all just common sense.

For atlassing, please do your map work at home. Check the co-ordinates when obtaining your altitude, measure your nearest named place, and pleases don't forget the details of locality. Please ensure your GPS gives readings in decimal minutes and not seconds, or decimal degrees.

Note: We have had GPS localities with errors of 50km! Do not buy the cheapest GPS. Ensure that the 'internal map' the GPS is using is the correct one for southern Africa. Also somehow in the field, it seems easier to misread - check carefully. If someone is reading out the data to you, insist on them calling each digit separately and in order - "vier en twintig" gets written 24 as often as 42.