When it comes to technology, no star is shining as bright as the Global Positioning System (GPS). GPS has been around since 1978, but it is only in the past several years that prices have come down enough to make this technology attainable for most state coastal programs.
What Is GPS?
GPS is a satellite-based radio navigation system that was first developed and operated by the U.S. Department of Defense. The system uses a series of satellites positioned around the Earth in such a way that usually five to eight satellites are accessible at any time of the day from anywhere in the world.
GPS receivers obtain the latitude, longitude, and altitude of their position by determining the length of time it takes for radio signals from orbiting satellites to reach the receivers. The resultant accuracy is generally very high for latitude and longitude, on the order of several meters, and somewhat less so for altitude.
For coastal resource managers, this information is used for any task where location information is important, including marking boundaries and mapping shorelines, monitoring erosion, assisting with dock permitting and other management plans, and tracking endangered animals.
Some Purchasing Considerations
As expected, there are a wide variety of options and costs associated with GPS. The following lists some of the points you might want to consider before making this purchase.
- Number of channels: The number of channels in a receiver determines how many satellites a receiver can read at once. Six-channel receivers usually get 10- to 15-meter accuracy in the field, while 12-channel receivers can get 5- to 10-meter accuracy.
- Data processing: Is it important to get accurate data while in the field? Or will taking the data back to the office to process suffice? In-the-field processing units can cost up to three times more.
- Data-logging capabilities: If you are going to use the data in a geographic information system (GIS), you will need the ability to log descriptive information. New field-based GIS packages allow you to directly integrate GPS data into your GIS.
Other considerations include power source options, antennae configuration, software compatibility, memory capabilities, and the ability of the unit to weather various natural elements (rain, saltwater, dust, sand, etc.).
To Get More Information
The National Oceanic and Atmospheric Administration (NOAA) Coastal Services Center offers GPS training in conjunction with several of its technology courses. Furthermore, the NOAA Pacific Services Center is writing a guidebook for GPS users in the Pacific Islands. While the guidebook includes information about special considerations for GPS users in the Pacific, the general information about prepurchasing decision making is applicable to those on the mainland as well.
Please e-mail Adam.Stein@noaa.gov if you would like to reserve a copy, or visit www.csc.noaa.gov to get information about the training courses.
