Doing GIS without GIS software

Some GIS research doesn't actually require GIS software.  Here's an example:

Download the Excel file of Delaware Census blocks and open it in Excel.  This file contains 23,241 Census block records, including land area (in square meters), 2010 population and housing unit counts, and interpolated longitudes and latitudes of block centroids.  I deleted a bunch of Census blocks that are entirely water, and included projected (DE State Plane NAD83 HARN meters) coordinates of the block centroids.

The CENSFIPS field is a unique block identifier (15 characters) concatenating four hierarchical geographies: STATE (2 chars), COUNTY (3 chars), TRACT (6 chars) and BLOCK (4 chars).  A block group ID is just the first character of the block ID.  The ZCTA5 field contains 5-character zip codes for each block. These should all be text (not numeric) fields so that leading zeroes are retained. 

Use Excel to calculate the following in DE State Plane coordinates:

  1. the area-weighted mean centroid of Delaware
  2. the area-weighted median centroid of Delaware
  3. the population-weighted mean centroid of Delaware
  4. the population-weighted median centroid of Delaware

Delaware has just three counties; in the COUNTY field 001=Kent, 003=New Castle and 005=Sussex.
Try calculating the same mean and median geographic and population centroids for each of the three counties.

If you want, you can check your answers against mine.