Introducing Geographic Information Systems with ArcGIS: A Workbook Approach to Learning GIS, 3rd Edition

Information

There are two simple ways of looking at a packet of information:

• A small amount of matter-energy with the potential to produce large effects
• A sequence of 1s and 0s—for example, 10100011

The poem “Paul Revere’s Ride” (excerpted) by Henry Wadsworth Longfellow, illustrates both:

LISTEN, my children, and you shall hear

Of the midnight ride of Paul Revere,

On the eighteenth of April, in Seventy-Five;

Hardly a man is now alive

Who remembers that famous day and year.

He said to his friend, “If the British march

By land or sea from the town to-night,

Hang a lantern aloft in the belfry arch

Of the North Church tower, as a signal light, —

One, if by land, and two, if by sea;

And I on the opposite shore will be,

Ready to ride and spread the alarm

Through every Middlesex village and farm,

For the country-folk to be up and to arm.”

[. . .]1

Meanwhile, impatient to mount and ride,

Booted and spurred, with a heavy stride

On the opposite shore walked Paul Revere.

Now he patted his horse’s side,

Now gazed on the landscape far and near,

Then, impetuous, stamped the earth,

And turned and tightened his saddle-girth;

But mostly he watched with eager search

The belfry-tower of the Old North Church,

As it rose above the graves on the hill,

Lonely and spectral and somber and still.

And lo! as he looks, on the belfry’s height

A glimmer, and then a gleam of light!

He springs to the saddle, the bridle he turns,

But lingers and gazes, till full on his sight

A second lamp in the belfry burns! ...