CODEWITHSUNDEEP
rgpsprojectiondistortionutm
Devon
Devon

Reputation: 29

How should I project my coordinates to UTM if they encompass multiple UTM zones?

My issue is that I am working on a really extensive dataset and that my tracking data encompass several UTM zones (12 to be specific: 32-33-34-35-36-37-38-39-40-41-42-43).

Snip of my data:

> head(springsub)
  id              DateTime            lat      lon      Altitude Sex Age Tag                 distance     time_interval velocity    velocity_kmh
1 N34234@1BF1A215 2022-03-15 10:42:00 45.50620 12.57837        5   1   6 GPS-GSM_TECHNOSMART      0.00000            NA          NA           NA
2 N34234@1BF1A215 2022-03-16 06:42:00 48.62932 20.51655      274   1   6 GPS-GSM_TECHNOSMART 695286.88086         72000 9.656762234  34.76434404
3 N34234@1BF1A215 2022-03-16 08:42:00 48.62761 20.51720      262   1   6 GPS-GSM_TECHNOSMART    195.38842          7200 0.027137281   0.09769421
4 N34234@1BF1A215 2022-03-16 10:42:00 48.62785 20.51662      271   1   6 GPS-GSM_TECHNOSMART     50.60765          7200 0.007028840   0.02530382
5 N34234@1BF1A215 2022-03-16 12:41:00 48.62737 20.51678      270   1   6 GPS-GSM_TECHNOSMART     54.77180          7140 0.007671121   0.02761603
6 N34234@1BF1A215 2022-03-16 18:42:00 49.30252 20.92450      914   1   6 GPS-GSM_TECHNOSMART  80799.38930         21660 3.730350383  13.42926138
utm_zone
1       33
2       34
3       34
4       34
5       34
6       34

Now many tracking data analysis workflows use Easting and Northing in UTM coordinates instead of longitude and latitude (which is what I have for now).

I tried projecting my tracks in UTM but obviously they get extremely distorted (when projecting around a "central" UTM zone).

# Project to UTM
llcoord <- st_as_sf(springsub[, c("lon", "lat")], coords =
c("lon", "lat"), crs = CRS("+proj=longlat +datum=WGS84"))
utmcoord <- st_transform(llcoord, crs = CRS("+proj=utm +zone=37
+datum=WGS84")) 

# Add Easting and Northing to data (in km)
data[, c("x", "y")] <- st_coordinates(utmcoord)/1000

What should I do? Splitting by UTM zones as in Converting latitude and longitude data to UTM with points from multiple UTM zones in R doesn't sound like a good idea considering that each track encompasses several zones and represents an individual movement.

Should I use a Lambert projection or an Equal Earth projection as in Projecting long/lat with multiple UTM zones instead?

Would that mean still using Easting and Norting metric information suitable for (as an example) a Hidden Markov Model analysis?

Thank you

Upvotes: 0

Views: 117

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