R/vms_export_tracks.R

In fishvice/ghsllr:

# Function to create vessel tracks for each vessel
#' Title
#'
#' @param d Standardized vms dataframe
#' @param file.name A character vector that
#'
#' @export
#' @export
vms_export_tracks <- function(d, file.name = "data-products/Vessel_tracks") {

  tracks <- list()
  ids <- unique(d$vid)

  for(i in 1:length(ids)){

    xy <-
      d %>%
      dplyr::filter(vid == ids[i],
                    dspeed > 0,
                    is.finite(dspeed)) %>%
      dplyr::select(lon, lat)

    if(nrow(xy) > 0) {
      tracks[[i]] <- sp::Lines(list(sp::Line(xy)), ID = ids[i])
    }

  }

  k <- unlist(lapply(tracks, class)) == "Lines"
  tracks <- tracks[k]
  tracks <-
    sp::SpatialLines(tracks, proj4string = sp::CRS("+proj=longlat +datum=WGS84")) %>%
    sp::SpatialLinesDataFrame(data = data.frame(vid = ids), match.ID = FALSE)

  rgdal::writeOGR(tracks,
                  dsn = ".",
                  layer = file.name,
                  driver = "ESRI Shapefile",
                  overwrite_layer = TRUE)

}