as.telemetry projection issue

[Amber Litterer]

Hi Chris,

I’m having some trouble bringing my data into as.telemetry with the correct projection and having the error columns recognized (COV.x.x, COV.x.y, COV.y.y). The projection of the error ellipses and the relocations are in EPSG:5070 (NAD 83/Albers Equal Area). The points fall in two UTM zones so I am unable to reproject into a UTM zone. If I run the as.telemetry function like so:

hr<-as.telemetry(as.data.frame(mylu.sf),

                 timezone = "US/Eastern",

                 keep = TRUE,

                 datum = "EPSG:5070",

                 projection = "EPSG:5070") I get the following warnings and errors: Geocentric coordinates not found. Looking for UTM coordinates.

UTM zone missing; assuming UTM zone="1N".

Warning: GDAL Error 1: PROJ: proj_create: Error 1027 (Invalid value for an argument): Unknown value for datumError in st_crs.character(from) :

  invalid crs: +proj=utm +zone=1 +datum=EPSG:5070

If I instead run the function like so:

hr<-as.telemetry(as.data.frame(mylu.sf),

                 timezone = "US/Eastern",

                 keep = TRUE,

                 projection = "EPSG:5070")

and then look at the summary(hr), the longitude and Latitude are -167.4037 and 17.74098 when they should be closer to -78 and 39.

I’ve also tried creating a movestack object first and then putting that into as.telemetry however the error columns I have are then not recognized in the code.

 I’d appreciate any insight you may have into this. I’m sharing the dataframe for two individual animals. Thank you for your help!

-Amber Litterer

[Christen Fleming]

Hi Amber,

I've coded as.telemetry() to import error ellipses in Argos format (long-lat) and in UTM format, but not other projections (it hadn't come up).

I will add that functionality to the to-do list, but for now you would want to convert your error-ellipses to long-lat and import that way.

There is example code in ctmm:::cov.xy2geo() that shows how to do this.

Also, your datum here would be "NAD83" for this projection, and the projection argument is what you want the output projection to be rather than the import. At least currently, the importing assumes Movebank format, which was long-lat or UTM coordinates, last I checked.

Best,

Chris