Create a filter index of a track for "bad" points with a combination of speed, distance and angle tests.
sda(x, smax, ang = c(15, 25), distlim = c(2.5, 5), pre = NULL)
| x | trip object |
|---|---|
| smax | maximum speed, in km/h |
| ang | minimum turning angle/s in degrees |
| distlim | maximum step lengths in km |
| pre | include this filter in the removal |
logical vector, with FALSE values where the tests failed
This is an independent implementation from that in the package argosfilter by Freitas 2008.
Freitas, C., Lydersen, C., Fedak, M. A. and Kovacs, K. M. (2008), A simple new algorithm to filter marine mammal Argos locations. Marine Mammal Science, 24: 315?V325. doi: 10.1111/j.1748-7692.2007.00180.x