Motorway and Dual carriageway
Using ArcInfo a fine 0.1 DM grid with a value of 1 for cells which contained
motorway or dual carriageway (selections from the communications network)
and a value of 0 otherwise was created. This grid was aggregated into 1,
2, 3, 5, 7, 11, 13 DM resolution grids with the values in each cell being
the sum of cells values in the fine grid. ArcView was then used to split
the higher level aggregations into the 1DM resolution so that all the grids
contained the same number of cells. The aggregations were then weighted
and summed together to produce the final input layer values.
Since the communications infrastructure appeared to be a good indicators
of where many people live it was selected from and maniputlated into various
different layers to provide extra information.
This layer appears to highlight more densely populated areas. By only looking
at aggregations upto 13 the information is still highly concentrated around
motorways and dual carriageways. As these roads are so important in todays
society it is likely that there influence on population patterns extends
beyond this and so a motorway and dual carriageway cost distance layer
may also be useful.