GPS
GPS stands for Global Positioning System. The system is a network of 24 satellites which circle the earth and can be used to triangulate the exact location of any point on the earths surface — provided you have a GPS unit to receive information. Such units communicate with the satellites and display your current latitude and longitude coordinates. GPS units can also be used to navigate toward known coordinates, which can be obtained from maps, or other GPS units.
The small hand-held GPS unit shown above (a Garmin® GPS 12) is easy to carry and use on long, difficult surveys when high accuracy is not important.
The large backpack GPS unit shown left (a Trimble Pro XRS receiver) is used when high-accuracy mapping is needed, e.g., mapping Jacquemontia reclinata along a transect in the coastal dune.
The Garden’s GIS Lab
Jennifer Possley, GIS Lab Coordinator/Field Biologist
GIS
Geographic Information Systems (GIS) are basically smart maps, linked in a computer to a database. For example, the photo shown here is a high-resolution aerial of the old entrance to the Garden (note the tram!). Blue points represent large trees that have been surveyed with a GPS unit. A GIS computer program, such as ArcView (© ESRI), allows you to click on one of the trees on the map to view information about it in tabular form.
The tree shown in red is the cannonball tree, Couropita guianensis (inflorescense to the right). The GIS tells you that at the tree is at 25.67609° north latitude and 80.27597° west longitude, it was flowering in April, and it is near Cycad Circle. The GIS can even hyperlink to a photo of the plant!
Our conservation team can use GIS to determine whether plant populations change over space or time. We can also use GIS in combination with vegetation maps or satellite imagery, for example, to determine which soils or plant communities are more likely to support that species, or whether it tends to grow in a certain density of tree canopy.
If you have been reading Garden Views for the past few years, or if you have ever been to Fairchild’s Research Center, then you may know that Fairchild has its very own “GIS Lab,” or Geographic Information Systems Laboratory.
The GIS Lab houses field biologists Sam Wright and myself, as well as much of the Research Center’s high-tech equipment. We have state-of-the-art GIS software and a large-format plotter for printing maps and posters. Field equipment includes a laser surveyor, electronic temperature and rain gauges, and a high-quality camera. We also have several GPS receivers, ranging from a hand-held unit with 45-ft accuracy, all the way to a large backpack unit with 3-ft accuracy.
Oops — like most tech-heads, I have already used two acronyms too many. If you are unfamiliar with these terms, please see the sideboxes for an explanation. Although, some readers may already know what “GIS”and “GPS” stand for. Those who work in public utilities or have done a search through their county property appraiser’s office may have used GIS. And anyone who is serious about fishing, lobstering, or boating may have used a hand-held GPS unit to aid in navigation back to that prime lobster hole or fishing spot.
I have always enjoyed the GPS and GIS aspects of my job. While there are downsides to everything (for example, sweating in the 95-degree heat while carrying a backpack and giant fiberglass pole; the horror of a dead battery when you are miles from the nearest store), there are definite bonuses. I’ve ridden on speedboats, canoes, helicopters, ATVs, and swamp buggies in order to map plants. I’ve crawled through dense brush to experience the quiet in areas where humans rarely go. Harrowing adventures I have shared with coworkers include getting stranded on an island at low tide, being chased by security personnel (who didn’t know what a GPS unit is), and being forced to use the GPS pole to vault over ditches. Working with a combination of GPS/GIS technology and field biology is a wonderful way to get to know the local flora. And with my GPS at my side (or as the case may be, strapped to me), I can never get lost.