** U.S. National Grid ― how it works**  

Very briefly stated, the U.S. National Grid breaks up the entire country into blocks.  The largest block is 100 km square.  This block in turn is divided into 100 blocks, each of which is 10 km square.  This is again subdivided into 100 blocks, each one being 1 km square.  Next are 100 blocks, each 100 m square, then 10 m square, then 1 m square, then 1 dm square, 1 cm, and so on.  Of course, each increasingly fine gradation makes sense only if you have sufficient precision to make such a close measurement.

How is any particular point identified within a square? By an x,y-coordinate system, in which the origin for every square is the bottom left. The bottom corresponds to the south and the left corresponds to the west.  Thus, as the x-value increases, you move to the east (geographers call this "easting") and as the y-value gets larger, you move north (which geographers call "northing").

** See an example of the U.S. National Grid in action**

Bailey Hall, University of Southern Maine

** Additional sites **

Federal Geographic Data Committee

** See my final project for Remote Sensing (USM; GEO205) for the fall semester of 2005**

Final Project

** ESRI certificates**

Sizing Up the Earth; Basics of ArcGIS
Python for Everyone Using ArcGIS 10.1
The 15-Minute Map: Creating a Basic Map in ArcMap
Getting Started with Cartographic Representations (for ArcGIS 10)
Cartographic Design Using ArcGIS 9


** My maps**

A Portion of the Scarborough (Maine) Marsh
The Hydorgraphy of Towson, Maryland: Drained by Three River Systems
Color theory
Choropleth map (color)
Choropleth map (grayscale): U.S. population growth rate
Graduated symbols map: Hurricanes
Graduated symbols map: European population
Cartogram: U.S. median income of states compared with their area