Moz CEO Rand Fishkin explains his process for creating a keyword map for SEO.
He summarizes the objective and explains how:
What we’re trying to get here is a picture of: Here are all the keywords that we’re trying to target. Here’s all the content that we have, and maybe we have keywords for all of that content. Maybe some of that content doesn’t have a keyword, those kinds of things. We’re trying to map these together so that we know what needs optimization, what new content needs to be built, what keywords need to be targeted to fit with which content, all of these types of things. This is how we identify the priorities and work that an SEO should be doing as they’re attacking a new site, attacking a new campaign.