Welcome to aniMotum Discussions! #28
Replies: 7 comments 4 replies
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Hello, Currently, I am using aniMotum's fit_ssm() function to fit a correlated-random walk to Argos satellite tracking data. However, I have a question regarding the "min.dt" argument within the function and am not sure if I interpret this argument correctly. The documentation says: "minimum allowable time difference between observations; dt <= min.dt will be ignored by the SSM". My first question is: what is the unit of the time difference, i.e. minutes, hours, days? My second question is: does that mean, that if I specify mind.dt = 10, if I have two consecutive detections that are less than e.g. 10 hours (?) apart they will be ignored? What is the intention of the min.dt argument - can it help to increase the goodness of model fit? If so, based on the literature it seems that SSMs have more issues with long time gaps, so would it be useful to have an argument that allows to specify long time gaps that should be excluded from the analysis? Thank you in advance! Vital |
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Hi, The unit is seconds. Your point re: SSM having issues with long time gaps in the data is correct, however, I've left it for researchers to decide how they want to address that problem. For example, two simple approaches are: 1) split tracks based on some data gap duration criterion prior to fitting the SSM; 2) split tracks after fitting the SSM by removing SSM-predicted locations in the data gaps. A future version of Thanks for asking the question. Ian |
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Hi, I have noticed in the vignettes/Move_persistence_models.Rmd page that you mention the mp model can only be fit to individuals separately. At present I have fitted it to a data set which has compiled the tracks from multiple tagged individuals - would this be inaccurate then? Is there an alternative option to add all the individual move persistence estimates onto one figure? |
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Hi, I am wondering whether this package currently has the functionality to simulate tracks biased towards set environmental conditions (For example warmer temperatures?) |
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Hey! I am wondering how to best integrate direct pathroutr functions, as currently I am running a mp model and then rerouting the points, but this will preserve the g values from the original modelling although rerouting might change these values? |
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There's no simple way to do this if you're fitting the |
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Hello Ian, I am trying to find the right commands for mapping individual tracks. So, instead of having them all together on the same map, I'd like to inspect the tracks of every animal (id) individually. What I did was to use the grab function and then just ggplotted every ID with a for loop, but then I missed out on all the nice features in the animotum package. Any idea how to code this inside of animotum? |
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