Words by Kevin Bolton
In recent times, I have been asked on a few occasions to do an article about co-ordinates. The reason is that with all the different coordinate formats now around, it’s hard to know which is right and which is wrong. The fact is that there is no right or wrong; what is best for your part of the world and for your application at the time. What aggravates the situation is that many people don’t understand co-ordinates, or which format to use for what application. To worsen the situation, the accompanying symbology is either not used, or used incorrectly. What adds to the problem is that many source documents, including books, maps and websites, mix and match co-ordinates without using the correct symbology. I say this in the light of the basic geography which we did in Standard 7; or what is now Grade 9.
If you have a good understanding of co-ordinates and co-ordinate systems, you will be able to correctly decipher the information, even if it is incorrectly displayed. However, people are not always aware of the issues relating to co-ordinate systems and how to get them to a common and understandable format. Today, we need to include the datum on which the co-ordinates are based. The reason is that we have old datums and new datums. When using a paper map, the datum is not an issue, but when relating it to a GPS or to GPS related co-ordinates, it becomes essential. If co-ordinates are displayed incorrectly and without a datum, the error is escalated beyond all logic. This could lead to your never finding your desired destination even if you know it well and getting lost even if you have a GPS. This is down to human, not technologyrelated error. Unfortunately, these errors are giving GPS a bad name, as the receivers are not performing as expected – even though it is a user problem. Remember, a good workman never blames his tools.