[OSM-newbies] Defining Areas

[James Ewen]

So, I've just started into my current obsession... mapping Strathcona
County, just east of Edmonton, Alberta, Canada.

I'm running into problems trying to learn how to get things done.

I want to define an area, that borders on another area. i.e. The
border between Strathcona County, and Elk Island National Park. These
two entities share a common border. I have defined Strathcona County
by drawing a way around the full extent of the county. I would assume
that you set the tag to boundary=civil or administrative for the
county, and boundary=national park for Elk Island.

What do you do about the shared border? It can only belong to one or
the other entity. All borders should be shared between two entities. I
saw an entry about defining the left and right sides of a boundary,
but do not understand how to use it. Has anyone figured these things
out, and have an practical examples to look at?

It seems to be very counter-intuitive to have to draw a common
boundary twice, once for each entity, especially if it is a very
convoluted boundary following for example a river.

James