average bearing of animal movement data

Previous Topic Next Topic
 
classic Classic list List threaded Threaded
5 messages Options
Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

average bearing of animal movement data

Alice Domalik
Hi there,

I have seabird tracking data and I have used both the packages 'trip' and 'move' to calculate the max distance travelled (using the function 'homedist' in 'trip', and 'distanceSummary' in 'move').
I would also like to describe the bearing of each animal when it is at its maximum displacement from the colony. I am wondering if anyone knows any packages that can calculate this. Alternatively, if someone knows how I can extract the coordinates of the location of maximum displacement.

thanks so much!

        [[alternative HTML version deleted]]

_______________________________________________
R-sig-Geo mailing list
[hidden email]
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

Re: average bearing of animal movement data

Barry Rowlingson
You can convert a "trip" object to a SpatialPointsDataFrame with
as("SpatialPointsDataFrame",my_trip). Then you can use functions like
"spDistsN1" from sp to compute the distance from "home" to each point,
find the maximum, and then use "bearing" from the "geosphere" package
to get the bearing for that row.

A complication I see is that this will only return the maximum
distance to a vertex point on the trip. For a trip in two flat
dimensions the maximum distance will always be a vertex point on the
trip but I think on a sphere its possible for great circles between
two points to have a location on the circle that is further from a
given point than either of the end points. But I can't get my head
quite round the 3d triangular geometry this early in the morning. For
small steps in a trip where you can approximate the geometry as flat
this is not a problem.

In contrast, the minimum distance from a trip to a "home" point is
rarely a vertex point on the trip because its possible for the trip
path to go very close to the home point in question. e.g a trip from
(10,0) to (-10,0) goes right through (0,0) but its points are both 10
units away.

Barry




On Wed, Aug 2, 2017 at 7:25 PM, Alice Domalik <[hidden email]> wrote:

> Hi there,
>
> I have seabird tracking data and I have used both the packages 'trip' and 'move' to calculate the max distance travelled (using the function 'homedist' in 'trip', and 'distanceSummary' in 'move').
> I would also like to describe the bearing of each animal when it is at its maximum displacement from the colony. I am wondering if anyone knows any packages that can calculate this. Alternatively, if someone knows how I can extract the coordinates of the location of maximum displacement.
>
> thanks so much!
>
>         [[alternative HTML version deleted]]
>
> _______________________________________________
> R-sig-Geo mailing list
> [hidden email]
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo

_______________________________________________
R-sig-Geo mailing list
[hidden email]
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

Re: average bearing of animal movement data

Michael Sumner-2
Also, trip is really outdated and dopey and homedist is likely not working
properly, very happy to help find he answers here there are many options.

Cheers, [hidden email]


On Thu, 3 Aug 2017, 17:27 Barry Rowlingson, <[hidden email]>
wrote:

> You can convert a "trip" object to a SpatialPointsDataFrame with
> as("SpatialPointsDataFrame",my_trip). Then you can use functions like
> "spDistsN1" from sp to compute the distance from "home" to each point,
> find the maximum, and then use "bearing" from the "geosphere" package
> to get the bearing for that row.
>
> A complication I see is that this will only return the maximum
> distance to a vertex point on the trip. For a trip in two flat
> dimensions the maximum distance will always be a vertex point on the
> trip but I think on a sphere its possible for great circles between
> two points to have a location on the circle that is further from a
> given point than either of the end points. But I can't get my head
> quite round the 3d triangular geometry this early in the morning. For
> small steps in a trip where you can approximate the geometry as flat
> this is not a problem.
>
>
>
> In contrast, the minimum distance from a trip to a "home" point is
> rarely a vertex point on the trip because its possible for the trip
> path to go very close to the home point in question. e.g a trip from
> (10,0) to (-10,0) goes right through (0,0) but its points are both 10
> units away.
>
> Barry
>
>
>
>
> On Wed, Aug 2, 2017 at 7:25 PM, Alice Domalik <[hidden email]> wrote:
> > Hi there,
> >
> > I have seabird tracking data and I have used both the packages 'trip'
> and 'move' to calculate the max distance travelled (using the function
> 'homedist' in 'trip', and 'distanceSummary' in 'move').
> > I would also like to describe the bearing of each animal when it is at
> its maximum displacement from the colony. I am wondering if anyone knows
> any packages that can calculate this. Alternatively, if someone knows how I
> can extract the coordinates of the location of maximum displacement.
> >
> > thanks so much!
> >
> >         [[alternative HTML version deleted]]
> >
> > _______________________________________________
> > R-sig-Geo mailing list
> > [hidden email]
> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
> _______________________________________________
> R-sig-Geo mailing list
> [hidden email]
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
--
Dr. Michael Sumner
Software and Database Engineer
Australian Antarctic Division
203 Channel Highway
Kingston Tasmania 7050 Australia

        [[alternative HTML version deleted]]

_______________________________________________
R-sig-Geo mailing list
[hidden email]
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

Re: average bearing of animal movement data

Kranstauber, Bart
Dear Alice,

Since Move inherits a SpatialPointsDataFrame the finding the location
furthers away can be done as follows (under the assumption the data are
longlat and the caveat pointed out by Barry):

 > require(move)
 > data(leroy)
 > which.max(spDistsN1(leroy, c(-40,40), longlat=T))
[1] 600

Best

Bart


On 03.08.2017 10:00, Michael Sumner wrote:

> Also, trip is really outdated and dopey and homedist is likely not working
> properly, very happy to help find he answers here there are many options.
>
> Cheers, [hidden email]
>
>
> On Thu, 3 Aug 2017, 17:27 Barry Rowlingson, <[hidden email]>
> wrote:
>
>> You can convert a "trip" object to a SpatialPointsDataFrame with
>> as("SpatialPointsDataFrame",my_trip). Then you can use functions like
>> "spDistsN1" from sp to compute the distance from "home" to each point,
>> find the maximum, and then use "bearing" from the "geosphere" package
>> to get the bearing for that row.
>>
>> A complication I see is that this will only return the maximum
>> distance to a vertex point on the trip. For a trip in two flat
>> dimensions the maximum distance will always be a vertex point on the
>> trip but I think on a sphere its possible for great circles between
>> two points to have a location on the circle that is further from a
>> given point than either of the end points. But I can't get my head
>> quite round the 3d triangular geometry this early in the morning. For
>> small steps in a trip where you can approximate the geometry as flat
>> this is not a problem.
>>
>>
>>
>> In contrast, the minimum distance from a trip to a "home" point is
>> rarely a vertex point on the trip because its possible for the trip
>> path to go very close to the home point in question. e.g a trip from
>> (10,0) to (-10,0) goes right through (0,0) but its points are both 10
>> units away.
>>
>> Barry
>>
>>
>>
>>
>> On Wed, Aug 2, 2017 at 7:25 PM, Alice Domalik <[hidden email]> wrote:
>>> Hi there,
>>>
>>> I have seabird tracking data and I have used both the packages 'trip'
>> and 'move' to calculate the max distance travelled (using the function
>> 'homedist' in 'trip', and 'distanceSummary' in 'move').
>>> I would also like to describe the bearing of each animal when it is at
>> its maximum displacement from the colony. I am wondering if anyone knows
>> any packages that can calculate this. Alternatively, if someone knows how I
>> can extract the coordinates of the location of maximum displacement.
>>> thanks so much!
>>>
>>>          [[alternative HTML version deleted]]
>>>
>>> _______________________________________________
>>> R-sig-Geo mailing list
>>> [hidden email]
>>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>> _______________________________________________
>> R-sig-Geo mailing list
>> [hidden email]
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>

_______________________________________________
R-sig-Geo mailing list
[hidden email]
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

Re: average bearing of animal movement data

Mathieu Basille-3
In reply to this post by Alice Domalik
An alternative solution would be to use adehabitatLT to prepare your
trajectories. If you set them to start at the colony (i.e. the first
location is at the colony), then you have nothing to do:

- ltraj objects provide the squared net displacement (R2n), which you can
use to find the furthest point from the colony (max R2n);

- ltraj objects provide absolute and relative bearings for each point, and
you already have the coordinates associated to it.

Hope this helps,
Mathieu.


On 08/02/2017 02:25 PM, Alice Domalik wrote:

> Hi there,
>
> I have seabird tracking data and I have used both the packages 'trip' and 'move' to calculate the max distance travelled (using the function 'homedist' in 'trip', and 'distanceSummary' in 'move').
> I would also like to describe the bearing of each animal when it is at its maximum displacement from the colony. I am wondering if anyone knows any packages that can calculate this. Alternatively, if someone knows how I can extract the coordinates of the location of maximum displacement.
>
> thanks so much!
>
> [[alternative HTML version deleted]]
>
> _______________________________________________
> R-sig-Geo mailing list
> [hidden email]
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>

--

Mathieu Basille

[hidden email] | http://ase-research.org/basille
+1 954-577-6314 | University of Florida FLREC

  « Le tout est de tout dire, et je manque de mots
  Et je manque de temps, et je manque d'audace. »
  — Paul Éluard


--

Mathieu Basille

[hidden email] | http://ase-research.org/basille
+1 954-577-6314 | University of Florida FLREC

  « Le tout est de tout dire, et je manque de mots
  Et je manque de temps, et je manque d'audace. »
  — Paul Éluard

_______________________________________________
R-sig-Geo mailing list
[hidden email]
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Loading...