Move point occurrences to the nearest raster cell with data

Move point occurrences falling in raster cells without data (NA) to the nearest raster cell with data.

points2nearestcell(
  locs = NULL,
  ras = NULL,
  layer = 1,
  move = TRUE,
  distance = NULL,
  table = TRUE,
  map = c("base", "ggplot", "leaflet", "none")
)

Arguments

locs

An sf::sf() or terra::SpatVector() object with point coordinates, e.g. as generated from locs2sf() or locs2vect().

ras

terra::SpatRaster() object.

layer

Integer. Raster layer to use for comparing with point locations (default = 1).

move

Logical. Change coordinates of points to those of the nearest raster cells? If FALSE, the function will show the nearest raster cells but coordinates of locs will not be changed.

distance

Numeric (optional). Maximum distance to move points. Point coordinates are only changed if the distance to the nearest raster cell is below distance.

table

Logical. Print table with old and new coordinates?

map

Character. One of "none", "base", "ggplot" or "leaflet", to choose the type of map showing the old and new point coordinates. See occmap().

Value

An sf::sf() or terra::SpatVector() object (with corrected coordinates if move is TRUE).

See also

https://search.r-project.org/CRAN/refmans/spatstat.geom/html/nearest.raster.point.html and https://search.r-project.org/CRAN/refmans/gecko/html/move.html.

Examples

## Generate example point coordinates and raster
locs <- data.frame(lon = c(1, 2, 1, 2, 2.2), lat = c(1.2, 1, 2.3, 3, 2))
locs.sf <- locs2sf(locs)
library(terra)
ras <- rast(nrows = 2, ncols = 2, xmin = 0.5, xmax = 3.5, ymin = 0.5, ymax = 3.5,
 resolution = 1, vals = c(NA, 1, 1, NA, NA, 1, NA, 1, 1))
occmap(locs.sf, ras, pcol = "black", psize = 3)


## Move point coordinates falling outside of raster
moved <- points2nearestcell(locs.sf, ras)
#> 3 out of 5 points have been moved.
#>     X   Y X_new Y_new      distance moved
#> 1 1.0 1.2     2     1 113377.05 [m]  TRUE
#> 2 1.0 2.3     2     3 135632.95 [m]  TRUE
#> 3 2.2 2.0     3     2  88901.89 [m]  TRUE

moved
#> Simple feature collection with 5 features and 0 fields
#> Geometry type: POINT
#> Dimension:     XY
#> Bounding box:  xmin: 2 ymin: 1 xmax: 3 ymax: 3
#> Geodetic CRS:  WGS 84
#>      geometry
#> 1 POINT (2 1)
#> 2 POINT (2 1)
#> 3 POINT (2 3)
#> 4 POINT (2 3)
#> 5 POINT (3 2)

## Move points only if moving distance is lower than specified threshold:
moved <- points2nearestcell(locs.sf, ras, distance = 100000)
#> 1 out of 5 points have been moved.
#>     X   Y X_new Y_new     distance moved
#> 1 1.0 1.2     1   1.2     0.00 [m] FALSE
#> 2 1.0 2.3     1   2.3     0.00 [m] FALSE
#> 3 2.2 2.0     3   2.0 88901.89 [m]  TRUE