Fix last coordinates

[dmarch]

Hi,
I am wondering if it is possible to fix not only the initial coordinates in a simulation, but also fix the last coordinates. This could be of high interest for simulating the movement of central place foragers, that return to their origin. Similar functionability is found in other packages like crawl or availability (e.g. https://australianantarcticdatacentre.github.io/availability/articles/availability.html).

[miguel-porto]

Hi,
Sorry, it is not possible at all to fix a destination because of the way the algorithm works, which is purely random directions with local bias. The best approximation that could be achieved would be to implement a biased random walk, where the simulation headings would have a further bias towards user-provided coordinates. Depending on the implementation, this might not guarantee that the animal would get to the points (e.g. it might be impeded to get there by high-resistance areas), but would at least bias the movement towards there.
But this feature is not yet implemented, even though it is part of the plan...

[dmarch]

Many thanks for checking for this issue, @miguel-porto. I will use the "availability" package for this specific feature while waiting for new developments in SimRiv. Not a problem for non-central place foragers. Congrats for the package!

[lontrenzo]

Hi David,
thank you for your interest in our package, and many apologies for our late reply!
As Miguel already said, we have a to do list and spatial bias in in fact a top priority in it. Hopefully sooner or later Miguel, who is the programmer and coded the software, could have time to dedicate to this. If you happen to be a programmer yourself and would like to help us develop SiMRiv however please just let us know, it would be great, as it will speed things up!

Also, I'm sending you the link to the article where SiMRiv was first divulgated (published on Movement Ecology last year, freely available here: https://movementecologyjournal.biomedcentral.com/articles/10.1186/s40462-019-0154-8), and another paper where we used the software in the field of road ecology (available here: https://www.researchgate.net/publication/337707737_Simulating_animal_movements_to_predict_wildlife-vehicle_collisions_illustrating_an_application_of_the_novel_R_package_SiMRiv).
I hope that you'll find the approach useful and use it in your research.

Best wishes!