Mapping Bedrock Outcrops with Stride & Compass and a GPS Unit in a soil and forest mantled landscape

Les Hasbargen
Earth Sciences, SUNY College at Oneonta
Author Profile


Students take a two mile hike along a trail in a forest and map bedrock exposures. The project takes place over a few days. Students will need 2-3 hours to collect the data in the field, and another 2-3 hours to create a digital map in the lab.

Used this activity? Share your experiences and modifications



This activity is designed for sophomore and junior geoscience majors at an undergraduate institution as part of a field data collection course. The exercise serves as an introduction to spatial data collection and integration.

Skills and concepts that students must have mastered

Students should be familiar with the traverse method of surveying using stride and a compass. They should know how to calibrate their stride. They should have mastered the conversion of stride and bearing data to local easting and northing coordinates in a spreadsheet. An appendix is included with the exercise which describes how to convert stride and bearing data into coordinates in Excel.

How the activity is situated in the course

This exercise is part of a sequence of data collection exercises that introduce students to mapping using stride and compass techniques, and then proceeds to more modern methods of data collection using total stations, GPS, and photogrammetry. A significant component of the course involves data conversion to get it into a computer-friendly format. This exercise is centered on that goal.


Content/concepts goals for this activity

Students learn how to collect data in the field, then convert and combine it with other spatial data in a computer-based environment.

Higher order thinking skills goals for this activity

Students exercise higher level decision-making during the mapping process, as they discriminate between actual bedrock outcrops and glacial erratics. Students develop map-making skills in a GIS environment, learning how to adequately combine data sets and present them in a clear and appealing fashion.

Other skills goals for this activity

Students master the technique of traverse mapping, and gain extensive practice measuring distance with strides and bearings with a compass. They learn how to record locations using a GPS receiver, and how to get that data into a computer. In addition, they learn how to use spreadsheets to perform extensive calculations in the conversion of raw distance-bearing data into GIS-ready coordinates. Students access online spatial data, and develop skills combining various data layers in GIS software. Group activity is highly recommended for this activity, as there are several techniques involved, and students learn a substantial amount from each other.

Description of the activity/assignment

In this exercise students map a trail and geologic outcrops along that trail using stride and compass and a GPS unit, and combine this data with other spatial data in GIS software. Students use the traverse method of surveying.
Learning objectives include:
  1. Students will develop observational skills in recognizing bedrock outcrops.
  2. Students will learn how to use a handheld GPS unit to map geologic features.
  3. Students will gain expertise with recording waypoints with the GPS unit.
  4. Students will gain expertise with translating tape-compass points into the UTM reference frame.
  5. Students will gain facility with inputting data into GIS software.
  6. Students will learn how retrieve free spatial data online.
  7. Students will learn how to manage and combine spatial data in a computer-based mapping environment.
  8. Students will develop skills in creating custom digital maps.

Determining whether students have met the goals

Students generate a map which combines all of their efforts. I utilize a weighted rubric to assess the quality of their effort. The map must have a meaningful title, author, date, scale, north indicator, mapped features, and legend. Each of these elements is evaluated with a qualitative rubric (0 = no credit; 1 = poor; 2 = fair; 3 = good; 4 = excellent), and grade is awarded based on a normalized weighted sum of the individual elements (A > 87.5%; B > 62.5%; C > 37.5%; D > 25%; F < 25%). Note that more weight is given to the mapped locations than other map elements.

More information about assessment tools and techniques.

Teaching materials and tips

Other Materials

Supporting references/URLs