yeah, exactly. I was helping my 6th grader last night on "Earth Science" (scoped at California) and we covered maps and their definition. One of the primary prerequisite for a map is having physical features like rivers, mountains etc.

Maps are just visualizations that focus on one attribute almost everything has: a spatial location. They don't need to show rivers or other physical features. A map of voting patterns for instance doesn't really have physical features. If you distort it to reflect population, you have an even looser map whose only tie to the world is the relative location of one area to another.

Physical maps like those that the USGS provide are just a tiny sample of the breadth of maps out there in the world. There are many, many really cool, non-traditional maps out there.

That certainly wasn't the definition in my high school geography classes, where we specifically covered maps that featured only political boundaries (and coincidentally, showed continental boundaries). It is also not a definition I could find in Wikipedia,Merriam-Webster, etc just now. Do you have any cites stronger than some 6th grade class?

So, to be clear, you're saying this is not a map: http://cdn.myzipcodemap.com/statemaps/CA.PDF; this is not a map: http://www.tfl.gov.uk/assets/downloads/standard-tube-map.pdf ...

The first one won't load for me. The second is a map, IMO... as it contains "physical features" like the train tubes, wheelchair ramps, bathrooms, etc