Pitney Bowes MapInfo Professional - Manual (Page 436)

• For more instructions about creating and adding redistricting features and other related topics, see
the Help System.
For additional topics in Redistricting, see Setting up the Target District in the Help System.
Using Redistricting
When you calculate the percentage of partial columns (such as population columns that cite income,
gender, age, ethnic background, or religious affiliation) you have two calculation methods available. One
method calculates the percentage by column so that the sum of all of the entries in every column would
be 100%. Another method calculates the percentage by row based on your selected row entry (or sum
of entries) so that each percentage entry in the row is calculated based on that row (or sum of entries).
For example, in the following table:
C B A
1 1 1
2 2 2
The Column method determines the percentages of entries in Column A:
Percentage (A1)=A1/(A1 + A2) x 100%; Percentage (A2)=A2/(A1 + A2) x 100%
The Row method determines the percentage for entries A1 and B1 based on C1 as a total column:
Percentage (A1) = A1/C1 x 100%; Percentage (B1) = B1/C1 x 100%
Selecting a valid base entry (or the sum of the entries) is crucial to returning meaningful results.
For example, if you choose a value in a population column and a base value from an income
column, your results will not be meaningful. Note:
• For more information, see Creating New Districts and Redistricting using the Row Method in the Help
System.
Options in Redistricting
To control the order of districts in the Districts Browser, on the Redistrict menu, click Options. The
Redistricter Options dialog box displays. Choose your preferred sort order from among: most recently
used, alphabetical, or unordered. You can also choose to show the Browser grid lines and save the
options as your default.
As mentioned earlier, the Most Recently Used option can greatly aid you if you have more districts than
the Districts Browser can display in a window. Whenever you select a map object that belongs to a district
that is not currently visible in the Browser, MapInfo Professional will move that record near the top of
the Browser window. You can then more easily set the new target district or view the changes in the
data fields as you carry out your load-balancing scenario.
MapInfo Professional 12.5 436
Redistricting-Grouping Map Objects into Districts