Special guest Emily Webster demonstrates how to use the ctmm (Calabrese et al. 2016; https://doi.org/10.1111/2041-210X.12559) R package to examine track outliers, telemetry errors, and autocorrelation timescales of GPS tracks. These are essential first steps when conducting movement analysis. Animal tracks from the free online platform Movebank are used.
--CHAT--
00:06:05 Emily: https://coder-tsv.slack.com/files/U0124J7HBQB/F036X74HLQ4/ctmm__1_.rmd
00:09:44 Kevin Bairos-Novak [JCU]: Yep!
00:18:54 Kevin Bairos-Novak [JCU]: In case anyone missed the dataset download
00:20:36 Kevin Bairos-Novak [JCU]: Can you change the tag ping rate while the tag is deployed?
00:20:45 Kevin Bairos-Novak [JCU]: For most trackers
00:21:24 Kevin Erickson: Some pay for frequency per ping, so you should be able to, or, you only pay to access some locations.
00:23:04 Kyana Pike: It depends largely on the device. For some GPS tags you would need to capture the animal again to reconfigure the tag as well.
00:27:36 Kevin Bairos-Novak [JCU]: Do calibration errors also depend on location sometimes? What would be like the optimal number of calibration points usually in a study of animals like albatross that move large distances and have GPS trackers?
00:28:12 Kevin Bairos-Novak [JCU]: As in, if you set up a calibration in the far northern hemisphere, is calibration error likely to be different from a location closer to the equator?
00:29:27 Kevin Bairos-Novak [JCU]: Thanks!
00:31:51 Kyana Pike: I’m not 100% but I think that position on the globe may also influence accuracy because the Earth does not have a uniform coverage from the satellites that we use to get GPS. Error will be influenced by how many sats were overhead at the time the device is trying to get a fix, the more sats the better
00:35:22 Kevin Bairos-Novak [JCU]: What does the blue line indicate? That the albatross moved a large distance in those points?
00:35:45 Kevin Bairos-Novak [JCU]: re: outlier plots
00:36:30 Kevin Erickson: Relative large speeds
00:36:35 Kevin Bairos-Novak [JCU]: Ah ok cool, thanks!
00:47:08 Kevin Bairos-Novak [JCU]: Still running for me
00:47:34 Kevin Erickson: Can you input variables rather than use the sliders?
00:48:06 Kevin Bairos-Novak [JCU]: @Kevin I’m sure you can, just has to be in the exactly correct format, so sliders are easier ;)
00:49:07 Kevin Bairos-Novak [JCU]: Is OU the default model? Or did we set this choice somewhere?
00:57:28 Kevin Erickson: Can it account for geological barriers? Mountain ranges, rivers, shorelines.
00:59:05 Kevin Erickson: Just 2D, right?
00:59:47 Kyana Pike: I think the developers are working on 3D home ranges as well now too!
00:59:57 Kyana Pike: For birds and things
01:01:38 Kevin Bairos-Novak [JCU]: My friend who does bathymetric kernels of fish complains about the trackers pinging and reflecting off the lake bottom, giving off false locations
01:02:55 Kyana Pike: thanks Em!!