cannot pass UTM zone to as.telemetry

[Jasja Dekker]

After searching through the conversations, I could not find a solution to my issue: I cannot seem to get my data into the right projection.

My data is a set consisting of locations from different sensors, so I could not work with nicely formatted movebank exports.

So I've converted my data from lat-long to UTM zone 31 using st_transform(data, 32631), extracted x and y and reformatted these with the subject and timestamp into a dataframe. 

Then I tried several ways to pass the projection, including adding the zone as a column called UTM.zone = "31" and the following:

myTelemetry <- ctmm::as.telemetry(df)

myTelemetry <- ctmm::as.telemetry(df, projection = CRS("+init=epsg:32631"))

 myTelemetry <- ctmm::as.telemetry(df,
                                   projection = sf::st_crs(32631)$proj4string)
 

myTelemetry <- ctmm::as.telemetry(df,
                                   projection = sf::st_crs(32631)$proj4string,
                                   UTM.zone= "+proj=utm +zone=31 +north +datum=WGS84 +units=m +no_defs")

But I keep getting "UTM zone missing; assuming UTM zone="1N"." message and when I ask for a summary(myTelemetry) it shows longitudes of -174 and lattitudes of ~53.  although plotting the data does look like it does in the original lat-long dataset.

This is driving me nuts. Is there a solution I am missing? Should I try reading in the WGS84 data?

Advice would be much appreciated! 

All the best,

Jasja