Is there a function to isolate rows of data based on the distance between the start and stop of their GPS coordinates?

Question

Budding ecologist here learning how to use R studio in data analysis. I'm research bison movements in the GYE to show where they cross highways - the data was stored on google looker studio after being transferred from old home-baked software. There are two types of sightings - static sightings and ones with a start and stop that show movement.

I need to isolate the rows that have start and stop data from the static ones in R, but the issue is that both static and start-stop rows have beginning and end linestring pathway data ( Ex: "LINESTRING(-111.097913 44.776748, -111.097813 44.776748)" ) - the static rows just have a negligible difference of 0.0001° for the longitude specifically, whereas the rows that show actual movement it's much greater. The latitude is consistent for static rows.

Is there a function that can separate row data based on the disparity between the two linestring longitude data points? I am a novice at R, taking lessons/exercises to build my skills so I'm not sure where to start for a function like this, but it seems possible. Any help is greatly appreciated!

I tried to create vectors with concatenated information based on the "LINESTRING" column, using subset(), but I couldn't find a way to isolate the data based on this kind of rule.

Answer 1

I would use sf::st_distance() between start/stop points or sf::st_length() on linestrings itself, like:

data.frame(
  geom = c("LINESTRING(-111.097913 44.776748, -111.097813 44.776748)", 
           "LINESTRING(-111.097913 44.776748, -111.097813 44.776848)", 
           "LINESTRING(-111.097913 44.776748, -111.097813 44.716748)"),
  n = c(1, 2, 3)
  ) |>
  sf::st_as_sf(wkt = "geom", crs = "EPSG:4326") |>
  dplyr::mutate(length = sf::st_length(geom))
#> Simple feature collection with 3 features and 2 fields
#> Geometry type: LINESTRING
#> Dimension:     XY
#> Bounding box:  xmin: -111.0979 ymin: 44.71675 xmax: -111.0978 ymax: 44.77685
#> Geodetic CRS:  WGS 84
#>   n                           geom          length
#> 1 1 LINESTRING (-111.0979 44.77...    7.893258 [m]
#> 2 2 LINESTRING (-111.0979 44.77...   13.636236 [m]
#> 3 3 LINESTRING (-111.0979 44.77... 6671.710745 [m]

and filter out those 'static' like:

[...]
  dplyr::mutate(length = sf::st_length(geom)) |>
  subset(length >= units::as_units(15, "m"))

#> Simple feature collection with 1 feature and 2 fields
#> Geometry type: LINESTRING
#> Dimension:     XY
#> Bounding box:  xmin: -111.0979 ymin: 44.71675 xmax: -111.0978 ymax: 44.77675
#> Geodetic CRS:  WGS 84
#>   n                           geom       length
#> 3 3 LINESTRING (-111.0979 44.77... 6671.711 [m]

^{Created on 2024-03-04 with reprex v2.1.0}