Assuming you do properly track all these things (by URL or custom variable), here are some ideas:
1) You can use segments (http://piwik.org/docs/segmentation/) to view only specific visitors. For example, you can narrow them down to a specific city.
2) When a row evolution (http://piwik.org/docs/row-evolution/) is displayed, you can “pick another row to compare” it to. This should allow you, for instance, to view visitors for inexpensive and classy appartments all in one graph.
Not sure whether this satisfies your need for “multi-dimensionality”, but those are good places to start.
1) You can use segments (http://piwik.org/docs/segmentation/) to view only specific visitors. For example, you can narrow them down to a specific city.
2) When a row evolution (http://piwik.org/docs/row-evolution/) is displayed, you can “pick another row to compare” it to. This should allow you, for instance, to view visitors for inexpensive and classy appartments all in one graph.
Not sure whether this satisfies your need for “multi-dimensionality”, but those are good places to start.