GIS supports ward redistricting


A ward is a legislative district within a city that has an elected
alderman. Park Ridge is made up of seven of these wards. Every ten
years, district boundaries may need to be redrawn to reflect changes in
the population based on the most recent census. Standard practice
involves keeping all of a city’s wards within 5% of each other
population wise, thus a boundary will only need to be redrawn if the
population numbers have skewed past that 5% threshold. In the case of
Park Ridge, there became a significant gap between the population counts
for Wards 3 and 4, thus causing the need for the boundary to shift. It
became evident that GIS would be the most effective tool to use to
redraw the ward boundaries and calculate the population shift that
occurred since the previous census.

Using census information at the block level from the 2010
Census, numerous maps were created with population counts from each
block for the City Clerk. The City Clerk would then use these maps to
create different scenarios of population shift that would be discussed
with each ward’s alderman. After multiple attempts, the area in question
was agreed upon and maps were produced for use at the City Council
meeting. Without GIS, the City Clerk would be forced to browse through
numerous census data and manually count the areas in question by hand,
which in turn would have been more time consuming, expensive, and less