## ** 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**

## ** Additional sites **

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

## ** ESRI certificates**

## ** My maps**