Re: Modified Preorder Tree Traversal - Advanced question
on reflection I am asking the wrong question. (It amazing how writing something down clarifies it in your head, isn't it ?)
Given a zoom of 4, how do I pull Scotland and England but not surrey ?
Put another way, given a zoom of x, I want to pull each node that has a zoom of less than x, but only the first one below x in each branch, not it's children.
To visualise it:
................UK(5)...................
************************
..Scotland(3)....England(3)......
.......................Surrey(1).......
I want ideally one query that will pull the top node from each branch below the **** line (ie Scotland and England) given the zoomlevel value 3 or 4.
Please bear in mind that the tree may not be even like this one and that the zoom value is in no way related to a region's depth in the tree.
The zoom value for a region actually represents the zoomlevel in google maps at which the region can clearly be made out. For example, Texas, being huge is going to have a different zoom value that conneticut, which is much smaller - even though they are both at the same depth in the region tree.
Yes I know this could be done with having a min zoom and a max zoom for each region, but I would rather not as this would make inserting a zoom level 4 in between the UK and Scotland, England cumbersome.