Census-to-Census Observations ...
When the Census Bureau takes a census count (or enumeration) for Unalaska, they start by specifying the boundaries of the area to be counted. This area (or sampling area) is a polygon and its shape can be quite complex - it may or may not match the geographical boundaries of Unalaska. It's important to note that from one Census to the next, the shape and location of the polygon can change.
If you need precision or details about the methodology of the Census, you should visit the U.S. Census Bureau for a definitive answer.
There is only a very minor difference in the sampling area given between the 2010 Census and the 2000 Census.
The 2010 Census shows that the total area for Unalaska was 212.7 square miles [550.8 km²]. Of this total, 111.8 square miles [289.5 km²] is land, with the balance (47.44%) being water (100.9 square miles [261.3 km²]).
The 2000 Census shows a total area of 212.3 square miles [549.9 km²]. Of this total, 111 square miles [287.5 km²] is land, with the balance (47.64%) being water (101.3 square miles [262.4 km²]).
While generally coinciding with the GPS location (latitude/longitude) of Unalaska, the latitude and longitude given by the Census Bureau actually indicates the GPS location of the polygon for Unalaska.
For the 2010 Census, the location was given as:
Lat: 53.913312° (or 53°54'47" N)
Lon: -166.525080° (or -166°31'30" W)
For the 2000 Census, the location given was:
Lat: 53.888984° (or 53°53'20" N)
Lon: -166.527239° (or -166°31'38" W)
The difference indicates that the U.S. Census Bureau moved the location of the polygon for the 2010 Census 8,881 feet to the north<4> of the location that was used in the 2000 Census.
The U.S. Geological Survey (USGS) and the U.S. Board on Geographic Names (BGN) have assigned a unique GNIS identifier (#2418866) to Unalaska. This identifier also marks a GSP point on the map, and that point lies within the boundaries of Unalaska. The GNIS point has been mapped to the latitude/longitude:
Lat: 53.930566° (or 53°55'50" N)
Lon: -166.549270° (or -166°32'57" W)
The GSP location given for the 2010 Census lies 8,157 feet to the southeast<5> of the point given by the GNIS for Unalaska. For more information about this and the relationship of the various Federal Codes, please visit our Misc Page for Unalaska.