Introduction to Topographic Maps Banner GeoSTAC Home Page Department of Geosciences ISU
by Jim Riesterer . . . . . . . . . . Edited by Scott Hughes, Dan Narsavage & Diana Boyack

Topographic Maps Tutorial

Introduction & Materials
What is a Map?
Using Topo Maps
Map Scale
Reference Datum
Map Projections
Grid Systems
State Plane
Public Land Survey
Vertical Scale
Creating Profiles
Vertical Exaggeration
Calculating Slope
Using a Compass
Magnetic Declination
Get a Bearing
Go from A to B
Find Self on a Map

Topographic Maps Field Exercises

Exercise 1
Exercise 2
Exercise 3
Exercise 4

GeoSTAC Home

Field Exercises
April 8, 2008

Exercise Two

Read and work through the entire companion tutorial, using links to visit more extensive explanations. Throughout the exercise, questions will be posed and answered. You will maximize what you get out of the tutorial if you work through the questions yourself before reading the answer, but you are not required to turn in your results.

Purpose: Gain practical experience with locating yourself on a topographic map and calculating your position using triangulation. Also learn some of the problems inherent in triangulation with imprecise tools and how you can overcome these problems.

* Go into your field area (visit public lands or, if on private land, go only after obtaining permission from the landowner ). Make your first stop somewhere that you are convinced you know where you are (such as a prominent bend in the road, a pond, etc.).

* Locate the point on the map, mark it with a small ‘x’, and record the point in both UTM and geographic coordinates.

* Find three other landmarks in your vicinity that you can recognize them on the map (prominent peaks, ponds, river bends, etc.).

* Using the technique outlined in the triangulation section of the online tutorial, use these points to triangulate your location. Be honest when you do this, as you will probably not get it exactly right the first time. Mark your calculated position with another small ‘x’.

* Measure the distance between your true and calculated positions and convert the distance to feet and meters, noting the direction in which your calculated position varies from your true position.

* Repeat this process for at least three more locations in your map area.

Upon returning from the field, complete a brief write up of your results. Include information about how far off your calculated position was from the true position. Were your errors were systematic (direction and distance)? Did your error decrease with practice? If you had not known exactly where you were, how could you have checked each of your calculated positions for accuracy?

Continue to . . . Exercise Three . . .