Economic models and geographical maps

At the Free Exchange blog they make a nice point about the use of models in economics by using an analogy between economic models and geographical maps.

Most are equilibrium models, which means they rely on a set of assumptions that rarely hold in the market. That does not diminish their value. Economic and financial models can be thought of as a map. If a map included every detail in the geography (trees, country roads, etc.) it would be intractable, rendering it useless. Maps do give you a sense of scale and how variables relate. This facilitates your journey, but does not eliminate unforeseen diversions and the potential for accidents.

Economic models aren't perfect, and they don't have to be, they just have to be better than the alternative. Economists know their models are not perfect and thus are constantly trying to improve them. But as with all models it is the ability to simplify, sensibly, that makes an economic model useful in the first place.

(HT: The visible hand in economics)