Measuring length of trajectories

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Measuring length of trajectories

Jeri Wisman
Hi all -

I am trying to measure the length of time of trajectories taken of seabird
movements to be able to relate time of flight to distance of flight. Any
suggestions of a function or package on how to measure the time? Thanks,

*Jeri Wisman* | Masters Candidate
Old Dominion University
Department of Biological Sciences
Mills Godwin Building, Room 312
Norfolk VA 23529 USA

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Re: Measuring length of trajectories

chris english-2
Jeri,

Is your data some kind of attached to bird(s) gps data?

Chris

On Thu, May 24, 2018 at 9:12 AM, Jeri Wisman <[hidden email]> wrote:

> Hi all -
>
> I am trying to measure the length of time of trajectories taken of seabird
> movements to be able to relate time of flight to distance of flight. Any
> suggestions of a function or package on how to measure the time? Thanks,
>
> *Jeri Wisman* | Masters Candidate
> Old Dominion University
> Department of Biological Sciences
> Mills Godwin Building, Room 312
> Norfolk VA 23529 USA
>
>         [[alternative HTML version deleted]]
>
> _______________________________________________
> R-sig-Geo mailing list
> [hidden email]
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>

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Re: Measuring length of trajectories

marta_TM
In reply to this post by Jeri Wisman
Hi Jeri,

there are a lot of packages to measure the tag trajectories length. You can
start reading about library(move) and library(gdistance)


2018-05-24 13:12 GMT+00:00 Jeri Wisman <[hidden email]>:

> Hi all -
>
> I am trying to measure the length of time of trajectories taken of seabird
> movements to be able to relate time of flight to distance of flight. Any
> suggestions of a function or package on how to measure the time? Thanks,
>
> *Jeri Wisman* | Masters Candidate
> Old Dominion University
> Department of Biological Sciences
> Mills Godwin Building, Room 312
> Norfolk VA 23529 USA
>
>         [[alternative HTML version deleted]]
>
> _______________________________________________
> R-sig-Geo mailing list
> [hidden email]
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>

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Re: Measuring length of trajectories

Michael Sumner-2
In reply to this post by Jeri Wisman
On Thu, 24 May 2018 at 23:32 Jeri Wisman <[hidden email]> wrote:

> Hi all -
>
> I am trying to measure the length of time of trajectories taken of seabird
> movements to be able to relate time of flight to distance of flight. Any
> suggestions of a function or package on how to measure the time? Thanks,
>

There are very many, including adehabitatLT package and the trackDistance
function in the trip package (I know how that one works so it's easy for me
to help with, but it's not as sophisticated as adehabitat family so
pros/cons).

Both packages requires you to get your data into the right format. There's
more general capability in sp::spDists which has arguments longlat (set to
TRUE for great circle distances from longlat) and segments, which gives
sequential paired distances. Both adehabitatLT and trip will handle the
grouping of locations into separate paths (ordered by time).

I'd say it's worth trying some of the purpose-built packages, because then
some of the metrics can be extracted very easily (once you know your way
around). Explore the "Moving objects, trajectories" section of this Task
View

https://gist.github.com/mdsumner/0a3cb0e58bf9d37b782943ac269e1eff

and this list of recentish additions, pending update to the Task View,
which gives a taste of how much activity there is in this space(!).

https://gist.github.com/mdsumner/0a3cb0e58bf9d37b782943ac269e1eff

Cheers, Mike.

>
> *Jeri Wisman* | Masters Candidate
> Old Dominion University
> Department of Biological Sciences
> Mills Godwin Building, Room 312
> Norfolk VA 23529 USA
>
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> R-sig-Geo mailing list
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--
Dr. Michael Sumner
Software and Database Engineer
Australian Antarctic Division
203 Channel Highway
Kingston Tasmania 7050 Australia

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