Data Partitioning based on polygon area
(May,2002, Ver2.0)
Search Key: Data Partitioner, demographic, census, aggregate, polygon, Calculate, area, transfer, compute
Extension interface:
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dataPart.gif: http://personal.bgsu.edu/~jdou/
EXAMPLE: ( included in the zip file )
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to calculate the population for a designed polygon in a boundary theme.
* boundary theme: designed polygon.
fields: shape, ID
* data theme: polygon theme, population field showing the population in each polygon.
fields: shape, ID, pop2000
* want to know the population of every polygon in boundary theme based on area
* output theme fields:
shape : copied from the boundary theme.
ID : copied from the boundary theme.
w_pop2000: population calculated,weighted based on area
s_pop2000: sum of all population of the polygons intersected with the bounday polygon.
NOTES:
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(1) also works for multiple fields.
(2) for checking overlapping polgyons, need a unique ID for each polygon. to check if there is some polygons overlapped by others.
(3) one potential problem is : if the field width is not long enought for the sum number, you may get an empty result. this problem occurs because I just copy the field defination of the field calculated to the output table. when the result number is too long, it overflows.
to avoid this problem, make the field to be calculated long enough for the sum result.
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Jianwei Dou - jdou@bgnet.bgsu.edu
Norman S. Levine - levinen@bgnet.bgsu.edu
Dept. of Geology
Bowling Green state Univ.
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