# Define Your Key Features Symbology with a Map Legend

Last Updated: Jan 27, 2018

A map legend defines different features in a map. It simply displays the symbol followed by a text description of what that symbol represents.

You find map legends everywhere… in subway maps, road maps and even in video game maps. And there’s no better way then to illustrate this with a couple of examples.

For example, some maps can have fifteen to twenty different symbols in them. And it’s hard for the reader to really understand each one. That’s why they need to reference a chart containing each symbol. That’s what map legends do.

Let’s take a look at map legend examples in cartography.

Whether you’re defining elements in a simple road map… map legends are one of those essential map elements that you absolutely need.

For example, if you are classifying soil orders like in the map below, how would you know what each color meant without a map legend. You can’t label each polygon as it would be cluttered in text.

This is an appropriate case for using one. Actually, map legends are the driving-force to understand what is in a map.

They are found everywhere from wind speeds like the Earth Null School map. In this case, it is a color ramp for wind speeds going from slow to fast.

Finally, the SwissTopo has a variety of different symbols for the reader to understand.

Now, you understand what is where in the map.

Imagine you’re lost in the woods. You’re in desperate need of food and water… and all you have is a road map and compass.

Your survival instincts begin to kick in.

You know where you are on the map, but it’s time to make some sense out of it.

So you pull out your map and it looks like this:

You begin to look at the features and line them up with the map legend.

Aha!

Blue means water. Green is forested area. Red and black lines define types of roads.

At this moment, you’re reading the map legend. The map legend contains all the symbols (symbology) used in the map to help the reader understand what the polygons, lines, points or grid cells represents.

So where should you go?

Your best bet is to march your way to the primary and secondary highways because natural features like water and forest is not a sure path to finding people. Certainly, gravel roads and abandoned roads are no guarantee either.

Certainly, the telephone in the south would be handy too!

It’s only because you could make sense out of a map legend that you could make that decision.

### What’s Next?

Cartographers simplify features in a map using symbols to represent real-world entities.

Sort of like a menu, these features in a map are defined in the map legend.

From simple topographic maps to complex geologic surveys, map keys (or map legends) are found in almost every single modern map.

Anything else you need to know? Drop a comment below.