TY - JOUR
T1 - The effects of interpolation error and location quality on animal track reconstruction
AU - Lonergan, Mike
AU - Fedak, Mike
AU - McConnell, Bernie
PY - 2009/4/16
Y1 - 2009/4/16
N2 - The Global Positioning System (GPS) gives precise estimates of location. However, the investigation of animal movement and behavior often requires interpolation to examine events between such fixes. We obtained 6,288 GPS locations from an electronic tag deployed for 170 d on an adult male gray seal (Halichoerus grypus) that ranged freely off the east coast of Scotland, and interpolated between subsamples of these data to investigate the growth of uncertainty within the intervals between observations. Average uncertainty over the path increased linearly as the interval between interpolating locations increased, reaching 12 km in longitude and 6 km in latitude at 2-d separation. The decrease in precision caused by duty-cycling, only collecting data in part of the day, was demonstrated. Adding noise to the GPS locations to simulate data from the ARGOS satellite system had little effect on the total errors for observations separated by more than 12 h. While the rate of growth in interpolation error is likely to vary between species, these results suggest that frequent, and preferably evenly spaced, location fixes are required to take full advantage of the precision of GPS data in the reconstruction of animal tracks.
AB - The Global Positioning System (GPS) gives precise estimates of location. However, the investigation of animal movement and behavior often requires interpolation to examine events between such fixes. We obtained 6,288 GPS locations from an electronic tag deployed for 170 d on an adult male gray seal (Halichoerus grypus) that ranged freely off the east coast of Scotland, and interpolated between subsamples of these data to investigate the growth of uncertainty within the intervals between observations. Average uncertainty over the path increased linearly as the interval between interpolating locations increased, reaching 12 km in longitude and 6 km in latitude at 2-d separation. The decrease in precision caused by duty-cycling, only collecting data in part of the day, was demonstrated. Adding noise to the GPS locations to simulate data from the ARGOS satellite system had little effect on the total errors for observations separated by more than 12 h. While the rate of growth in interpolation error is likely to vary between species, these results suggest that frequent, and preferably evenly spaced, location fixes are required to take full advantage of the precision of GPS data in the reconstruction of animal tracks.
KW - Animal tracking
KW - Location accuracy
KW - Movement models
KW - Path smoothing
KW - Pinniped
KW - Spatial precision
UR - http://www.scopus.com/inward/record.url?scp=64949154364&partnerID=8YFLogxK
U2 - 10.1111/j.1748-7692.2008.00264.x
DO - 10.1111/j.1748-7692.2008.00264.x
M3 - Article
AN - SCOPUS:64949154364
VL - 25
SP - 275
EP - 282
JO - Marine Mammal Science
JF - Marine Mammal Science
SN - 0824-0469
IS - 2
ER -