Lessons Index:
6. CHART MAKING FOR NAVIGATORS
Osher Map Library
University of Southern Maine
From Classical Mythology to Satellite Imagery
An exhibition at the Osher Map Library and Smith Center for Cartographic Education, University of Southern Maine, Portland, 4 April 2000 to 11 January 2001
Donald S. Johnson, guest curator
Lesson 1e: Presentation of the
Lesson
MAP AND CHART
Osher Map Library Lesson
Charting Neptune's Realm
Lenora Liebowitz, Peter Rice, Andy Alley
E. Presentation of the Lesson
(Item) (Activity) (Time/Elapsed Time)
1. Opening Statement (1 min/1 min)
We can follow the trail of those who have gone before us across the
land. The settlers who traveled west of the Mississippi on the Oregon Trail
had only to follow the trail laid down by those who had gone ahead of them.
Even today, we can follow that trail because the thousands of wagons used
in that great westward migration cut furrows so deeply into the sod of
the plains and the stone of the Rocky Mountains that they can still be
seen. This is not true of the ships that sail the broad oceans. There are
no trails left in the water.
As a result, mariners had to develop a different sort of way to follow the trails laid down by their predecessors. We call those special nautical maps charts. They have a different set of realities from the road maps we are used to seeing.
Today we will examine a map and a chart of the same area. You will get a chance to draw one of each type using the 'sign posts' common to each.
2. Map (Show United States Geological Survey Maine
Portland Sheet)(3 min/4 min)
a. Aids to navigation
1. Street signs
2. Points of interest
b. Hazards to
navigation
1. One way markers
2. Off/On ramps
3. Chart (Show United States Coast and Geodetic
Survey Chart of Casco Bay) (5 min/9 min)
a. Aids to navigation
1. Buoys
2. Spires, Chimneys
b. Hazards to
Navigation
1. Shoal (shallow) water
2. Underwater cables
4. Drawing Maps (12 min/21 min)
a. Distribute
copies of blank port sheet
b. Have students
draw a city on the land areas which includes:
1. Streets
2. Factories (with chimneys)
3. Churches with spires
4. Height of land
5. Drawing Charts (21 min/42 min)
a. Distribute
second copy of blank port sheet
b. Have students
draw a chart on the water areas including:
1. Chimneys (from the road map)
2. Spires (from the road map)
3. Height of land
4. Channel buoys (cans and nuns)
5. Shoals and Sand Bars
6. Depths and Bottom Type
6. Review main points and clarify student questions (2 min/44 min)
7. Closing Statement (1 min/45 min)
The surface of the water may appear to be a blank sheet, but to the mariner his chart shows where it is safe to go, and where there areas that need to be avoided. Without those marks, navigating around the harbor would be as difficult as driving through the city without street signs, stop lights, or building numbers.
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