Best Projection for ctmm and rsf.fit

[Victória]

Hello ctmm community,

I am a bit confused about the best projection to use when working with ctmm. When I try to change the projection of telemetry objects, I get the error:

"A projected coordinate system must be specified."

From what I understand, ctmm requires a Cartesian (meter-based) projection, so I structured my entire workflow using UTM.

However, when I use rsf.fit with this UTM projection, I get the warning:

"## Warning in .local(x, ...): This function is only useful for Raster objects with a longitude/latitude coordinates"*

At the same time, I noticed that a UTM projection is used in the buffalo/Cilla example provided in the documentation and in the animove materials.

To work around this issue, I used an equivalent projection (+proj=eqc +datum=WGS84 +units=m +no_defs), which seems to work fine, but I’m not sure if this is the best approach.  

Given this, I would like to ask:

1. What projection would you recommend using for consistency with ctmm and rsf.fit?

2. What are the potential issues with using rsf.fit with an utm projection like:

   "+proj=utm +zone=24 +south +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs"

Thank you !

[Jesse Alston]

Hi Victória,

Tracking data is reprojected automatically when telemetry objects are made, so there is never any need to reproject telemetry objects. Rasters should be projected in a lat/long projection.

Jesse

Sent via mobile--I apologize for excess brevity

On Feb 4, 2025, at 10:43 AM, Victória <victori...@gmail.com> wrote:



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