Database Reference
In-Depth Information
Thisisasimpleprocedurethatgivesusanestimateof130,288peoplelivingwithin
1mileofthetrail.But,lookingattheshapeoftheselection,wecanseethatweare
over-estimatingthepopulationbytakingtheentiretyoftheblockgroupsinourestim-
ate.
Similarly, if we just used the block groups whose centroids lay within 1 mile of our
proposed trail alignment, we would underestimate the population.
Instead, we will make some useful assumptions. Block groups are designed to be
moderatelyhomogenouswithintheblockgroup.Assumingthatthisholdstrueforour
data,wecanassumethat,foragivenblockgroup,if50percentoftheblockgroup
is within our target area, we can attribute half of the population of that block group
toourestimate.Applythistoallourblockgroups,sumthem,andwehavearefined
