Cobweb of flows - The Visualization of Spatial Social Structure - page 192

One problem, which has held back work on understanding census migration
statistics, has been the method by which flows have been amalgamated when too
few people were involved, to a higher spatial resolution. The solution to this prob-
lem is similar to that of the changing constituency boundaries earlier - it does
not matter. Just as a series of election results can be drawn while the boundaries
change, so the lines on the map need not all be between wards but can be between
amalgamations, as long as the basic populations of the areas involved are used
to determine their significance. 17 In fact, the Census Office may even have done
researchers a favour in amalgamating, creating clearer images of the basic move-
ments, which can be coloured according to the attributes of the migrants.

6.7 A space of flows

The process is one of deprived people being left in the urban priority
areas as the successful move out to middle Britain.
(Halsey, 1989, p. 22)

Images of migration, the average distance and direction can be drawn, at
resolutions as fine as the ward level. These pictures show that migration is a
much more diffuse process than commuting. 18 Propensity is most useful; coupled
with distance it gives us an idea of how often and how far people move house. 19
Without being able to see the structure of individual streams we are blind to the
pattern. We have to guess what there is to see.
Between the ten thousand wards in Britain there could be as many as one
hundred million migration streams. In fact only one per cent of these actually
occur in a year - one million streams carried some five million people between
the years 1980 and 1981. The flows are generally equal in magnitude in both
directions. If we amalgamate these two flow propensities as a geometric mean
and plot only those that are significantly large, merely one hundred thousand

17 'Over Great Britain as a whole, the pattern of gross migration levels seems to reflect the political
map remarkably well, for Labour Party strongholds correspond quite closely to places where little
migration takes place' (Hollingsworth, 1970, p. 33). Contrast this with Hollingsworth's statement
above about subordinates moving more. Although appearing contradictory, both statements can and
do hold true.
18 People have been able to travel further to work as car ownership has spread: 'Social changes
are likely to add to economic changes in loosening up the pattern of settlement in the industrial
regions of Britain in the next generation' (Lawton, 1968, p. 39).
19 'Most migrants had moved short distances. In 1981, of those moving within Great Britain
about 69 per cent moved less than 10 kilometres (six miles) and only 13 per cent moved more
than 80 kilometres (50 miles) - distances measured as the straight-line distance between the grid
reference of the address a year before census and the grid reference of the enumeration district of
the usual address at census' (Brant, 1984, p. 23).