MAPS.

This is about how you use a map to get from one place to another.

1. Location.

A map is a copy of the real world. So you can locate yourself in the real world by locating where you are on the map. How do you locate where you are on the map? (In the absence of GPS.)

You can use features around you. Look at a feature near you and then find where it is, ie find its representation, on the map. Usually this requires both the real life feature and it’s representation to be named. And for the map to have an index. So you see a street with the street sign ‘Green Street’. And then the map has an alphabetical list of streets. This says ‘Green Street’ and gives grid co-ordinates on the map. So then you know where you are on the map.

If the features in real life aren’t labelled then you could go by their appearance instead. A small pond with some trees next to it. Then find that feature on the map.

A featureless map, even though it might be accurate, is useless: see the blank map from The Hunting of the Snark.

A map is frustratingly worthless if you can’t locate yourself on it. Sometimes I will be out somewhere and I will see a map of the surrounding area fixed to a wall. But it won’t have a ‘you are here’ marker so it doesn’t help!

2. Orientation.

The second thing is, you need some way of establishing which way you are facing. You might know where you are on the map but if you don’t know which way you are facing then that’s no good.

If you don’t have a compass then the way to find out which way you are facing is to find something else on the map where the map shows which way that is facing. Such as a road. If Green Street runs north south then once you have located yourself on Green Street you are almost there to which way you are facing.

If all the objects in the area were perfectly circular then you couldn’t do this because a circle doesn’t point. In that case you would need to locate two objects together and see which way those two items were oriented on the map.

3. Representation.

Third, a map needs to be an accurate representation of the area. In particular a representation of the kinds of things that are are a help (eg roads) or a hindrance (eg rivers and mountains) to moving about in the area. Because the main use of a map is to help you get from one place to another.

If the area is just a flat terrain then this is not an issue. Then location and orientation are enough for you to be able to use the map to get from one place to another. But if there are rivers and suchlike then these need to be shown on the map.

Having a map is like having the ability to look down from above and seeing where you are in relation to other things.

4. Map and area.

Suppose you lived somewhere where all three of the above things were present in the real world. So at regular intervals there were signs which said what the map grid reference location of that sign was. And something to say which way North was where the sign was.

And also where there wasn’t much that would get in the way of you moving about. And the roads were all regular laid out so you wouldn’t need to be told where the roads were. In other words, a city laid out on a grid system.

5. Directions.

There is an alternative to maps for finding your way about. This is directions. Most of the time you are travelling to somewhere you’ve been many times before and you use directions that you have memorised. Just knowing your way about somewhere is a different sort of information to map information. It doesn’t consist of you having a map in your head somehow. If you know how to get from A to B that doesn’t mean you have internalised a map of the area that includes A and B in your head. If, instead of maps, you could just have books of directions.