Laboratory Exercise 2

Differentially Correcting the Data


"The Global Positioning System and GIS, An Introduction", Michael Kennedy, Ann Arbor Press, 1996, Part 2, ISBN 1-57504-017-4.


This laboratory consists of an introduction to the use of the Trimble's GeoExplorer II mapping system consisting of a pocket sized GPS data collector and Pathfinder Office - GPS processing software.

In this exercise, you will learn the basics of transferring the data file obtained and stored in the GeoExplorer II in Laboratory Exercise 1 to the PC, using the Pathfinder Office software. Using the Pathfinder Office software, you will also learn how to display the data, differentially correct the data, and print a copy of the map.

For more information on these concepts, refer to the Trimble website.


With the supervision of your instructor, or lab coordinator, checkout the same GeoExplorer II unit your group used in Laboratory Exercise 1, being sure that the battery is fully charged and connected to the GeoExplorer II. To move between menus, use the ESC key to move up the menu chain, and the CMD key (the one in the center with the yellow diamond) to move down the menu chain Use the UP and DOWN arrow keys to change numeric information.

A. Transferring Rover files and Downloading Base Files

B. Obtaining Base Station Differential Correction Files

C. Differentially Correcting the Data

D. Displaying the Uncorrected Rover file and the Corrected file.


Group Leader Name

Group Member Names

Group Leader Email

What is the distance between the furthest points of the uncorrected data?

What is the name of the base file you downloaded?

What is file name for the differentially corrected data?

What is the distance between the furthest points of the corrected data?

If this from for some reason does not work, submit your answers by way of e-mail to the address below. Be sure keep a copy of the report for your own records and to submit a copy of your map to the instructor.