scholarly journals Shearwaters know the direction and distance home but fail to encode intervening obstacles after free-ranging foraging trips

2019 ◽  
Vol 116 (43) ◽  
pp. 21629-21633 ◽  
Author(s):  
Oliver Padget ◽  
Geoff Stanley ◽  
Jay K. Willis ◽  
Annette L. Fayet ◽  
Sarah Bond ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Large Scale ◽  
Positioning System ◽  
Global Positioning ◽  
Displacement Experiments ◽  
Integration Mechanisms ◽  
Gps Tracks ◽  
Free Ranging ◽  
Manx Shearwater ◽  
Pelagic Seabird

While displacement experiments have been powerful for determining the sensory basis of homing navigation in birds, they have left unresolved important cognitive aspects of navigation such as what birds know about their location relative to home and the anticipated route. Here, we analyze the free-ranging Global Positioning System (GPS) tracks of a large sample (n = 707) of Manx shearwater, Puffinus puffinus, foraging trips to investigate, from a cognitive perspective, what a wild, pelagic seabird knows as it begins to home naturally. By exploiting a kind of natural experimental contrast (journeys with or without intervening obstacles) we first show that, at the start of homing, sometimes hundreds of kilometers from the colony, shearwaters are well oriented in the homeward direction, but often fail to encode intervening barriers over which they will not fly (islands or peninsulas), constrained to flying farther as a result. Second, shearwaters time their homing journeys, leaving earlier in the day when they have farther to go, and this ability to judge distance home also apparently ignores intervening obstacles. Thus, at the start of homing, shearwaters appear to be making navigational decisions using both geographic direction and distance to the goal. Since we find no decrease in orientation accuracy with trip length, duration, or tortuosity, path integration mechanisms cannot account for these findings. Instead, our results imply that a navigational mechanism used to direct natural large-scale movements in wild pelagic seabirds has map-like properties and is probably based on large-scale gradients.

Causes and Consequences of Timing Errors Associated With Global Positioning System Collar Accelerometer Activity Monitors

2014 ◽  
Vol 5 (2) ◽  
pp. 372-379 ◽  
Author(s):  
Adam J. Gaylord ◽  
Dana M. Sanchez
Keyword(s):  
Global Positioning System ◽  
Animal Behavior ◽  
Cervus Elaphus ◽  
Activity Monitor ◽  
Positioning System ◽  
Activity Monitors ◽  
Timing Errors ◽  
Global Positioning ◽  
Free Ranging ◽  
Monitor Data

Abstract Direct behavioral observations of multiple free-ranging animals over long periods of time and large geographic areas is prohibitively difficult. However, recent improvements in technology, such as Global Positioning System (GPS) collars equipped with motion-sensitive activity monitors, create the potential to remotely monitor animal behavior. Accelerometer-equipped activity monitors quantify animal motion with different amounts of movement presumably corresponding to different animal activities. Variations in motion among species and differences in collar design necessitate calibration for each collar and species of interest. We paired activity monitor data collected using Lotek GPS_4400 collars worn by captive Rocky Mountain elk Cervus elaphus nelsoni with simultaneously collected behavior observations. During our initial data screening, we observed many sampling intervals of directly observed behavior that did not pair to activity monitor data in a logical fashion. For example, intervals containing behaviors associated with little or no motion sometimes aligned with relatively high activity monitor values. These misalignments, due to errors associated with collar timekeeping mechanisms, would likely result in inaccurate classification models. We corrected timing errors by using defined breaks in animal behavior to shift times given by collar output, improving the average correct classification rate 61.7 percentage points for specific behaviors. Furthermore, timing errors were significantly reduced by increasing the GPS fix rate, by using a sampling interval divisible by 8 seconds, and by accurately timing the initial collar activation. Awareness and management of collar timing error will enable users to obtain the best possible estimates of true behavior when calibrating these collars and interpreting data from free-ranging animals.

scholarly journals UAV ONBOARD GPS IN POSITIONING DETERMINATION

2016 ◽  
Vol XLI-B1 ◽  
pp. 1037-1042
Author(s):  
K. N. Tahar ◽  
S. S. Kamarudin
Keyword(s):  
Coordinate System ◽  
Global Positioning System ◽  
Large Scale ◽  
Control Point ◽  
Critical Issue ◽  
Ground Control ◽  
Positioning System ◽  
Ground Control Points ◽  
Global Positioning ◽  
Point Positioning

The establishment of ground control points is a critical issue in mapping field, especially for large scale mapping. The fast and rapid technique for ground control point’s establishment is very important for small budget projects. UAV onboard GPS has the ability to determine the point positioning. The objective of this research is to assess the accuracy of unmanned aerial vehicle onboard global positioning system in positioning determination. Therefore, this research used UAV onboard GPS as an alternative to determine the point positioning at the selected area. UAV is one of the powerful tools for data acquisition and it is used in many applications all over the world. This research concentrates on the error contributed from the UAV onboard GPS during observation. There are several points that have been used to study the pattern of positioning error. All errors were analyzed in world geodetic system 84- coordinate system, which is the basic coordinate system used by the global positioning system. Based on this research, the result of UAV onboard GPS positioning could be used in ground control point establishment with the specific error. In conclusion, accurate GCP establishment could be achieved using UAV onboard GPS by applying a specific correction based on this research.

Evaluation of a soft-copy photogrammetry system for tree-plot measurements

1993 ◽  
Vol 23 (9) ◽  
pp. 1781-1785 ◽  
Author(s):  
P.A. Gagnon ◽  
J.P. Agnard ◽  
C. Nolette
Keyword(s):  
Global Positioning System ◽  
Large Scale ◽  
Tree Height ◽  
Aerial Photographs ◽  
Positioning System ◽  
Crown Diameter ◽  
Forest Inventories ◽  
Global Positioning ◽  
Soft Copy

This article describes and evaluates the application of a soft-copy photogrammetry system to large-scale forest inventories. A specially designed software, developed by the authors, has been investigated in terms of accuracy and general operability. Tests based on 1:1100 color aerial photographs, taken with a 10-m cross-boom system and digitized at resolutions of 300, 450, and 600 dots per inch, confirmed the expected tree-height accuracies of 48, 32, and 24 cm, respectively. This indicates that a photographic scale of 1:800 and a scanning resolution of 800 dots per inch could produce a tree-height precision of the order of 10 cm. The tests have shown that model orientation takes about 15 min; for a tree plot of 24 trees, measurements (height and crown diameter) and observations (species and condition) also take about 15 min. As the important problem of positioning a helicopter over a tree plot has now been solved using global positioning system receivers, the results and information presented in this paper indicate that the existing technology can provide a rigorous and operational photogrammetric system for large-scale forest inventories and regeneration monitoring.

An Off-Site Approach to Late Iron Age and Roman Landscapes on the Northern Plateau, Spain

2013 ◽  
Vol 16 (2) ◽  
pp. 289-313 ◽  
Author(s):  
Jesús García-Sánchez ◽  
Miguel Cisneros
Keyword(s):  
Iron Age ◽  
Global Positioning System ◽  
Large Scale ◽  
Survey Methodology ◽  
Field Survey ◽  
Positioning System ◽  
Late Iron Age ◽  
Castilla Y Leon ◽  
Global Positioning ◽  
New Settlements

Since 2009, a large-scale archaeological field survey – the Ager Segisamonensis Survey Project – has been carried out on the Northern Plateau of the Iberian Peninsula, in the Burgos province (Castilla y León), Spain. The aim of this project is to understand the Iron Age/Roman transition in terms of settlement strategies and landscape exploitation. The field survey has been undertaken in the landscape surrounding an Iron Age settlement and the successive Roman city of Segisamo – modern Sasamón. The goal is not the discovery of new settlements, but the recognition of the so-called ‘dwelling landscape’ and its evolution. In this article, we highlight our field survey methodology based on hand-held Global Positioning System (GPS) instruments and the creation of a recording system of ‘aggregation units'.

scholarly journals Manx shearwater (Puffinus puffinus) rafting behaviour revealed by GPS tracking and behavioural observations

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7863
Author(s):  
Cerren Richards ◽  
Oliver Padget ◽  
Tim Guilford ◽  
Amanda E. Bates
Keyword(s):  
Global Positioning System ◽  
Wind Direction ◽  
Gps Tracking ◽  
Wind Condition ◽  
Breeding Colony ◽  
Large Colony ◽  
Remote Island ◽  
Global Positioning ◽  
Gps Tracks ◽  
Manx Shearwater

Before visiting or leaving their remote island colonies, seabirds often engage in a behaviour termed ‘rafting’, where birds sit, often in groups, on the water close to the colony. Despite rafting being a widespread behaviour across many seabird taxa, the functional significance of rafting remains unknown. Here we combine global positioning system (GPS) tracks, observational and wind condition data to investigate correlates of rafting behaviour in Manx shearwaters (Puffinus puffinus) at a large colony on Skomer Island, Wales. We test (1) the influence of wind direction on rafting location and (2) whether raft size changes with respect to wind speed. Our approach further allows us to describe day-night trends in (3) raft distance from shore through time; (4) the number of birds present in the nearshore waters through time; and (5) spatial patterns of Manx shearwater rafts in marine waters adjacent to the breeding colony. We find no evidence that wind direction, for our study period, influences Manx shearwater rafting location, yet raft size marginally increases on windier days. We further find rafting birds closer to the shore at night than during the day. Thus, before sunset, birds form a “halo” around Skomer Island, but this halo disappears during the night as more individuals return from foraging trips and raft nearer the colony on Skomer Island. The halo pattern reforms before sunrise as rafts move away from land and birds leave for foraging. Our results suggest that wind conditions may not be as ecologically significant for rafting locations as previously suspected, but rafting behaviour may be especially important for avoiding predators and cleaning feathers.

scholarly journals Prospects of GIS-Passportization of Natural Plague Foci in the Territory of the Russian Federation

2012 ◽  
pp. 48-53
Author(s):  
A. A. Kuznetsov ◽  
A. M. Porshakov ◽  
A. N. Matrosov ◽  
E. V. Kuklev ◽  
V. B. Korotkov ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Large Scale ◽  
Spatial Differentiation ◽  
Topographic Maps ◽  
Positioning System ◽  
Gis Technologies ◽  
Global Positioning ◽  
The Russian Federation ◽  
Methodological Approaches ◽  
High Degree

Characterized in brief are the results of natural plague foci passportization carried out in the late XX century. Evaluation of the principle of formalized spatial differentiation between enzootic territories is made. The principle can guarantee high degree of data ordering, obtained in the process of epizootiological surveillance. Therefore, prospects of a new stage of plague foci passportization based on GIS-technologies are viewed, the strategy is determined, and methodological approaches for its realization are put forward. Large-scale implementation of digital topographic maps and global positioning system into the work of plague control organizations is accentuated.

scholarly journals Estimating experienced racial segregation in US cities using large-scale GPS data

2021 ◽  
Vol 118 (46) ◽  
pp. e2026160118
Author(s):  
Susan Athey ◽  
Billy Ferguson ◽  
Matthew Gentzkow ◽  
Tobias Schmidt
Keyword(s):  
Global Positioning System ◽  
Large Scale ◽  
Racial Segregation ◽  
Gps Data ◽  
Income Mobility ◽  
Positioning System ◽  
Global Positioning ◽  
Highly Correlated ◽  
Transit Use ◽  
Us Cities

We estimate a measure of segregation, experienced isolation, that captures individuals’ exposure to diverse others in the places they visit over the course of their days. Using Global Positioning System (GPS) data collected from smartphones, we measure experienced isolation by race. We find that the isolation individuals experience is substantially lower than standard residential isolation measures would suggest but that experienced isolation and residential isolation are highly correlated across cities. Experienced isolation is lower relative to residential isolation in denser, wealthier, more educated cities with high levels of public transit use and is also negatively correlated with income mobility.

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