Published December 16, 2019 | Version v1
Dataset Open

Less is more: on-board lossy compression of accelerometer data increases biologging capacity

  • 1. Netherlands Institute of Ecology
  • 2. MadeByTheo
  • 3. University of Amsterdam

Description

  1. GPS-tracking devices have been used in combination with a wide range of additional sensors to study animal behaviour, physiology and interaction with their environment. Tri-axial accelerometers allow researchers to remotely infer the behaviour of individuals, at all places and times. Collection of accelerometer data is relatively cheap in terms of energy usage, but the amount or raw data collected generally requires much storage space and is particularly demanding in terms of energy needed for data transmission.
  2. Here we propose compressing the raw ACC data into summary statistics within the tracking device (before transmission) to reduce data size, as a means to overcome limitations in storage and energy capacity.
  3. We explored this type of lossy data compression in the accelerometer data of tagged Bewick's swans (Cygnus columbianus bewickii) collected in spring 2017. By using software settings in which bouts of 2 s of both raw ACC data and summary statistics were collected in parallel but with different bout intervals to keep total data size comparable, we created the opportunity for a direct comparison of time budgets derived by the two data collection methods.
  4. We found that the data compression in our case yielded a 6 time reduction in data size per bout, and concurrent, similar decreases in storage and energy use of the device. We show that with the same accuracy of the behavioural classification, the freed memory and energy of the device can be used to increase the monitoring effort, resulting in a more detailed representation of the individuals' time budget. Rare and/or short behaviours such as daily roost flights, were picked up significantly more when collecting summary statistics instead of raw ACC data (but note differences in sampling rate). Such level of detail can be of essential importance, for instance to make a reliable estimate of the energy budgets of individuals.
  5. In conclusion, we argue that this type of lossy data compression can be a well-considered choice in study situations where limitations in energy and storage space of the device pose a problem. Ultimately these developments can allow for long-term and nearly continuous remote-monitoring of the behaviour of free-ranging animals.

Notes

Funding provided by: NWO-NPP
Crossref Funder Registry ID:
Award Number: 866.15.206

Files

2min_ann_ss_aqf_213.csv

Files (243.6 MB)

Name Size Download all
md5:7120ec58058b4960ba11231e5a018171
21.7 MB Preview Download
md5:968aa48113c0607cb714298af9fd1aa9
19.3 MB Preview Download
md5:e6d96172367847d64fdae291e70b6c31
20.7 MB Preview Download
md5:abf99d796b4011cfa45350a1b588bff8
22.2 MB Preview Download
md5:466c81246d7001dd6b395a9458506b0a
23.4 MB Preview Download
md5:a2c2e73090dc2a93350f1c62effd0c90
22.0 MB Preview Download
md5:8ab51e597c06b41332aa9298ed48d6b5
22.0 MB Preview Download
md5:cfdb91e2e648c223b03815bcb99b64f1
21.7 MB Preview Download
md5:e38229d75068168b42e31598047e3a7f
19.6 MB Preview Download
md5:9228d2952bb47ebbd63ea54ff238cc37
23.9 MB Preview Download
md5:fb5622fe2ff6b3f98e24d7754f927629
2.6 MB Preview Download
md5:4c44883526d4c26fc657f06fcfed086f
2.4 MB Preview Download
md5:5db8c944d4541289a669ca2b188b189a
2.8 MB Preview Download
md5:23f1388fa35e870e43e23ab95f4e6279
2.7 MB Preview Download
md5:f8cef391802a1d1a0998c67b377e27c8
2.9 MB Preview Download
md5:ee6c579b851152ac4c1acc75e208eece
2.7 MB Preview Download
md5:8d1e9cdc9416303c82beaced15bf0316
2.7 MB Preview Download
md5:c4d046a8aebcaf99509581fa34105949
2.7 MB Preview Download
md5:ac3b519ad2dcaf1d32ec7cc1e0560cc6
2.7 MB Preview Download
md5:840d12d8ef7c906b2552115d0987e096
2.9 MB Preview Download