I would like to estimate (with uncertainty) the cumulative distance traveled by an organism between two specific time periods. Let's say that I used the find.times.distribution function to identify that a tagged bird most likely commenced spring migration on 1 April 2016 and most likely reached its breeding grounds on 23 April 2016.
I would like to sum the distance traveled by that bird between every consecutive twilight from 1 April to 23 April. The ideal final result would be something like, "The cumulative spring distance traveled between 1 April and 23 April was median=1034.2 km (95% credible interval: 650.2 to 1840.2 km).
But I cannot figure out a 'good' way to estimate the uncertainty component.
One (non-parsimonious) solution would be:
1) generate 95% isopleths (with the plot_util_distr function) for every twilight [or perhaps just every day] between 1 April and 23 April,
2) generate 1000 random points (assuming a uniform distribution) within the confines of each 95% isopleth,
3) create 1000 paths/polylines that run between all 23 isopleths (using a single point in each isopleth),
4) and finally measure the length of those 1000 paths and create summary statistics (median, mean, 0.25 and 0.975 percentile values).
I had been trying to modify the get_ZI_distances function in FlightR to avoid my non-parsimonious solution, but I have so far failed miserably. Hopefully a better programmer than myself can provide some help.
I would like to estimate (with uncertainty) the cumulative distance traveled by an organism between two specific time periods. Let's say that I used the find.times.distribution function to identify that a tagged bird most likely commenced spring migration on 1 April 2016 and most likely reached its breeding grounds on 23 April 2016.
I would like to sum the distance traveled by that bird between every consecutive twilight from 1 April to 23 April. The ideal final result would be something like, "The cumulative spring distance traveled between 1 April and 23 April was median=1034.2 km (95% credible interval: 650.2 to 1840.2 km).
Getting the median cumulative distance is easy:
But I cannot figure out a 'good' way to estimate the uncertainty component.
One (non-parsimonious) solution would be:
1) generate 95% isopleths (with the plot_util_distr function) for every twilight [or perhaps just every day] between 1 April and 23 April,
2) generate 1000 random points (assuming a uniform distribution) within the confines of each 95% isopleth,
3) create 1000 paths/polylines that run between all 23 isopleths (using a single point in each isopleth),
4) and finally measure the length of those 1000 paths and create summary statistics (median, mean, 0.25 and 0.975 percentile values).
I had been trying to modify the get_ZI_distances function in FlightR to avoid my non-parsimonious solution, but I have so far failed miserably. Hopefully a better programmer than myself can provide some help.
Thank you and cheers,
Jason Hill
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