Limits...
Accuracy of ARGOS locations of Pinnipeds at-sea estimated using Fastloc GPS.

Costa DP, Robinson PW, Arnould JP, Harrison AL, Simmons SE, Hassrick JL, Hoskins AJ, Kirkman SP, Oosthuizen H, Villegas-Amtmann S, Crocker DE - PLoS ONE (2010)

Bottom Line: The ARGOS errors measured here are greater than those provided by ARGOS, but within the range of other studies.Locations of species that make short duration dives and spend extended periods on the surface (sea lions and fur seals) had less error than species like elephant seals that spend more time underwater and have shorter surface intervals.Supplemental data (S1) are provided allowing the creation of density distributions that can be used in a variety of filtering algorithms to improve the quality of ARGOS tracking data.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, United States of America. costa@biology.ucsc.edu

ABSTRACT

Background: ARGOS satellite telemetry is one of the most widely used methods to track the movements of free-ranging marine and terrestrial animals and is fundamental to studies of foraging ecology, migratory behavior and habitat-use. ARGOS location estimates do not include complete error estimations, and for many marine organisms, the most commonly acquired locations (Location Class 0, A, B, or Z) are provided with no declared error estimate.

Methodology/principal findings: We compared the accuracy of ARGOS Locations to those obtained using Fastloc GPS from the same electronic tags on five species of pinnipeds: 9 California sea lions (Zalophus californianus), 4 Galapagos sea lions (Zalophus wollebaeki), 6 Cape fur seals (Arctocephalus pusillus pusillus), 3 Australian fur seals (A. p. doriferus) and 5 northern elephant seals (Mirounga angustirostris). These species encompass a range of marine habitats (highly pelagic vs coastal), diving behaviors (mean dive durations 2-21 min) and range of latitudes (equator to temperate). A total of 7,318 ARGOS positions and 27,046 GPS positions were collected. Of these, 1,105 ARGOS positions were obtained within five minutes of a GPS position and were used for comparison. The 68(th) percentile ARGOS location errors as measured in this study were LC-3 0.49 km, LC-2 1.01 km, LC-1 1.20 km, LC-0 4.18 km, LC-A 6.19 km, LC-B 10.28 km.

Conclusions/significance: The ARGOS errors measured here are greater than those provided by ARGOS, but within the range of other studies. The error was non-normally distributed with each LC highly right-skewed. Locations of species that make short duration dives and spend extended periods on the surface (sea lions and fur seals) had less error than species like elephant seals that spend more time underwater and have shorter surface intervals. Supplemental data (S1) are provided allowing the creation of density distributions that can be used in a variety of filtering algorithms to improve the quality of ARGOS tracking data.

Show MeSH

Related in: MedlinePlus

The ARGOS error measured as offset from the “true” position of the animal as compared to GPS locations are given in this figure.Note the logarithmic scaling of the lower panel and linear scaling of the upper panel.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2806907&req=5

pone-0008677-g003: The ARGOS error measured as offset from the “true” position of the animal as compared to GPS locations are given in this figure.Note the logarithmic scaling of the lower panel and linear scaling of the upper panel.

Mentions: ARGOS position errors from the animal borne tests were centered on “true” locations but extreme outliers were numerous and did not occur in a circular-uniform distribution (Fig. 3). Similarly, for the direction frequency of ARGOS errors, the east/west (longitudinal) error component was large relative to the north/south component (latitudinal) (Fig. 4).


Accuracy of ARGOS locations of Pinnipeds at-sea estimated using Fastloc GPS.

Costa DP, Robinson PW, Arnould JP, Harrison AL, Simmons SE, Hassrick JL, Hoskins AJ, Kirkman SP, Oosthuizen H, Villegas-Amtmann S, Crocker DE - PLoS ONE (2010)

The ARGOS error measured as offset from the “true” position of the animal as compared to GPS locations are given in this figure.Note the logarithmic scaling of the lower panel and linear scaling of the upper panel.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2806907&req=5

pone-0008677-g003: The ARGOS error measured as offset from the “true” position of the animal as compared to GPS locations are given in this figure.Note the logarithmic scaling of the lower panel and linear scaling of the upper panel.
Mentions: ARGOS position errors from the animal borne tests were centered on “true” locations but extreme outliers were numerous and did not occur in a circular-uniform distribution (Fig. 3). Similarly, for the direction frequency of ARGOS errors, the east/west (longitudinal) error component was large relative to the north/south component (latitudinal) (Fig. 4).

Bottom Line: The ARGOS errors measured here are greater than those provided by ARGOS, but within the range of other studies.Locations of species that make short duration dives and spend extended periods on the surface (sea lions and fur seals) had less error than species like elephant seals that spend more time underwater and have shorter surface intervals.Supplemental data (S1) are provided allowing the creation of density distributions that can be used in a variety of filtering algorithms to improve the quality of ARGOS tracking data.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, United States of America. costa@biology.ucsc.edu

ABSTRACT

Background: ARGOS satellite telemetry is one of the most widely used methods to track the movements of free-ranging marine and terrestrial animals and is fundamental to studies of foraging ecology, migratory behavior and habitat-use. ARGOS location estimates do not include complete error estimations, and for many marine organisms, the most commonly acquired locations (Location Class 0, A, B, or Z) are provided with no declared error estimate.

Methodology/principal findings: We compared the accuracy of ARGOS Locations to those obtained using Fastloc GPS from the same electronic tags on five species of pinnipeds: 9 California sea lions (Zalophus californianus), 4 Galapagos sea lions (Zalophus wollebaeki), 6 Cape fur seals (Arctocephalus pusillus pusillus), 3 Australian fur seals (A. p. doriferus) and 5 northern elephant seals (Mirounga angustirostris). These species encompass a range of marine habitats (highly pelagic vs coastal), diving behaviors (mean dive durations 2-21 min) and range of latitudes (equator to temperate). A total of 7,318 ARGOS positions and 27,046 GPS positions were collected. Of these, 1,105 ARGOS positions were obtained within five minutes of a GPS position and were used for comparison. The 68(th) percentile ARGOS location errors as measured in this study were LC-3 0.49 km, LC-2 1.01 km, LC-1 1.20 km, LC-0 4.18 km, LC-A 6.19 km, LC-B 10.28 km.

Conclusions/significance: The ARGOS errors measured here are greater than those provided by ARGOS, but within the range of other studies. The error was non-normally distributed with each LC highly right-skewed. Locations of species that make short duration dives and spend extended periods on the surface (sea lions and fur seals) had less error than species like elephant seals that spend more time underwater and have shorter surface intervals. Supplemental data (S1) are provided allowing the creation of density distributions that can be used in a variety of filtering algorithms to improve the quality of ARGOS tracking data.

Show MeSH
Related in: MedlinePlus