Border Frequency On All Maps

Border Frequency On All Maps
Map Generated : 10:08:18 02/24/2006

This map is attempt to aggregate all maps of all regions submitted by all project participants. The map shows how often a given box is part of a border between 2 regions, or between a region and a non-region. Boxes with dark shading were part of a border on many maps, while areas of light shading were rarely part of a border (they tended to be in the same region as neighboring boxes

Because users submit widely varying names and locations for their regions, it isn't possible to show on a single map 'where' all these regions are. Instead, this map attempts to show where the borders between regions tend to be.

Methods
Each of the 600 boxes on the map began with a score of 0. Each box on each map was examined sequentially, and compared to its neighbors above, below, to the left, and to the right. If any of those 4 boxes were in a different region, or in no region at all, the box's score was incremented by 1. Boxes on the edge of the map had only 3 comparisons done, and boxes in the corners had only 2 comparisons done.

By this method, the highest score a box could recieve would be ((total # of maps) * 4). This score would be achieved only if a certain box was in a different region from all its neighbor boxes on every single map submitted. In actuality, the highest scores recieved were significantly lower than this.

After a score was computed for every box, the raw scores were grouped into percentiles by comparing each box's score to the highest score found. That highest scoring box becomes the '100%' percentile. All other boxes became part of another percentile range ('90-99%', '80-89%', etc.).

Shades of gray were assigned to all percentile ranges. Darker shading represents a higher score, and lighter shading represents a lower score.

Observations
There are a few spans of territory which clearly seems to be regional boundaries, regardless of what users actually called those regions.

One runs from Virginia to Arkansas, before turning south through Louisiana.
Another divides Texas from all areas surrounding it.
Ohio and western Pennsylvania are 'border' territory on a very high percentage of maps.
Another common border runs from this area south through West Virginia to join the Virginia- Arkansas border.
It seems common to create a north-south border from west Texas through the western Dakotas.
Washington and Oregon seems separated from most regions around them.
The interior west, from the Texas-Dakotas line to the Pacific coast, has borders running all through it with no clear pattern, indicating that there is little concensus about how to divide this area into regions.

Percentile	Number of Boxes	% of Map
Map Colors Key
00	207	36.90
10	55	9.80
20	56	9.98
30	60	10.70
40	55	9.80
50	44	7.84
60	31	5.53
70	28	4.99
80	16	2.85
90	8	1.43
100	1	0.18

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