Introduction

The Global Positioning System (GPS) has become the most common mapping tool for participatory scale mapping. GPS is a mapping tool that is extremely sophisticated, yet quite simple to use and relatively affordable. GPS involves using a hand-held receiver that receives satellite signals and automatically calculates the position of a place according to a coordinate system. GPS data is in the form of coordinates that can be processed manually on a base map or digitally by downloading to mapping software on a computer.

This Unit explains how the GPS works. It also gives an overview of different types of GPS receivers and factors to consider in selecting a GPS receiver appropriate for a given mapping project. The GPS has given rise to new technologies, such as smartphones with GPS capabilities.

This Unit covers how to use a GPS receiver in the field, how to design and conduct a field survey and how to record data. It then looks at Cybertracker – software that can be customised and used on a smartphone or hand-held computer and connected to a GPS to record geo-referenced observations in the field.

Although GPS data is commonly and efficiently downloaded directly to a computer, this Unit emphasises manual techniques for recording, organising and plotting GPS data. Those involved in participatory mapping should always be able to handle GPS data manually because being able to explain the system and where the data came from demonstrates understanding and transparency.

Unit objectives / expected outcomes

After the completion of the Unit the trainee will be able to:

• explain how GPS works in a graphic and simple way;
• describe types of GPS receivers;
• discuss advantages and disadvantages of smartphone navigation;
• describe the main features of GPS receivers and select an appropriate GPS tool for a project;
• control errors in the accuracy of GPS systems as far as possible;
• adjust a GPS receiver for the local area;
• use a GPS receiver in the field and collect and record GPS data in a systematic way;
• design a GPS survey appropriate to the purpose of the mapping project (e.g. thematic information in focus, size of area, type of landscape);
• plot GPS data on a base map.

Content outline, main topics covered and suggested sequencing

This Unit focuses on the topics listed below.

1. Mapping with GPS (PPT No. 1: Mapping with GPS) (45 min)
2. Setting up and using a GPS receiver in the field (Exercise No. 1: Using a GPS Receiver)(60 min)
3. Planning a GPS survey (Exercise No. 2: Planning a GPS Survey) (30 min)
4. Plotting GPS coordinates on a map grid (Exercise No. 3: Plotting Coordinates) (60 min)

Components of the Unit

Exercises

• Exercise No. 1: Using a GPS Receiver; to set up a GPS receiver for the local area and to find and record coordinates using a GPS receiver (60 min)
• Exercise No. 2: Planning a GPS Survey; to discuss the factors and decisions to consider in planning a GPS survey (30 min)
• Exercise No. 3: Plotting Coordinates; to plot coordinates on a topographic map using the most common grid systems (i.e. latitude-longitude and UTM), to articulate how the coordinates are found and to create a grid reference tool for plotting coordinates on a map (60 min)

Handouts for Trainee (to be distributed in printed format):

• Mapping with GPS (Handout4T)
• Article: Nicaragua's GPSistas Mapping their Lands on the Caribbean Coast
• Article: Integrating Traditional Knowledge with Computer Science for the Conservation of Biodiversity
• Additional Resources
• Unit Glossary (included in the Module Glossary)

Presentations

• PPT No. 1: Mapping with GPS; using coordinates from satellite signals to determine absolute locations on earth (45 min)

Duration

3 ½ hours

Additional trainer resources

• Operation manual for particular GPS unit being used in the training.
• Cybertracker website. Source: Cybertracker Conservation
  http://tinyurl.com/md8hys
• Global Positioning Overview Source: Peter H. Dana, The Geographer's Craft Project, Department of Geography, The University of Colorado at Boulder
  http://tinyurl.com/4wyc
• Make your own maps. Source: Rich Owings author of GPS Mapping: Make your own maps
  http://makeyourownmaps.com
• Dana, Peter H. 1998. Nicaragua’s “GPSistas”: Mapping Their Lands on the Caribbean Coast. GPS World. Pages 32-41.
  http://www.iapad.org/publications/ppgis/GPSWSep98.pdf
• Hofmann-Wellenhoff, B., H. Lichtenegger, J. Collins. 2001 GPS Theory and Pracitce. USA. Springer-Verlag.

Equipment needed

GPS receiver(s) (per group of trainees), topographic map or other base map (optional), sketch map from exercises in Module M08 (if available), field notebooks (one per trainee), field pencil and eraser, colour pencils, ruler, UTM grid, list of GPS coordinates (i.e. sample coordinates determined by the trainer or actual coordinates taken in survey exercises), large sheet of graph paper or plain paper, ruler and long straight-edge

Additional downloads

• Download this page in MS Word format (additional information included)
• Download the complete unit