Manage PROJ search path and network settings

sf_proj_search_paths(paths = character(0))

sf_proj_network(enable = FALSE, url = character(0))

sf_proj_pipelines(
  source_crs,
  target_crs,
  authority = character(0),
  AOI = numeric(0),
  Use = "NONE",
  grid_availability = "USED",
  desired_accuracy = -1,
  strict_containment = FALSE,
  axis_order_authority_compliant = st_axis_order()
)

Arguments

paths

the search path to be set; omit if no paths need to be set

enable

logical; set this to enable (TRUE) or disable (FALSE) the proj network search facility

url

character; use this to specify and override the default proj network CDN

source_crs

object of class `crs` or character

target_crs

object of class `crs` or character

authority

character; constrain output pipelines to those of authority

AOI

length four numeric; desired area of interest for the resulting coordinate transformations (west, south, east, north, in degrees). For an area of interest crossing the anti-meridian, west will be greater than east.

Use

one of "NONE", "BOTH", "INTERSECTION", "SMALLEST", indicating how AOI's of source_crs and target_crs are being used

grid_availability

character; one of "USED" (Grid availability is only used for sorting results. Operations where some grids are missing will be sorted last), "DISCARD" (Completely discard an operation if a required grid is missing) , "IGNORED" (Ignore grid availability at all. Results will be presented as if all grids were available.), or "AVAILABLE" (Results will be presented as if grids known to PROJ (that is registered in the grid_alternatives table of its database) were available. Used typically when networking is enabled.)

desired_accuracy

numeric; only return pipelines with at least this accuracy

strict_containment

logical; default FALSE; permit partial matching of the area of interest; if TRUE strictly contain the area of interest. The area of interest is either as given in AOI, or as implied by the source/target coordinate reference systems

axis_order_authority_compliant

logical; if FALSE always choose ‘x’ or longitude for the first axis; if TRUE, follow the axis orders given by the coordinate reference systems when constructing the for the first axis; if FALSE, follow the axis orders given by

Value

`sf_proj_search_paths()` returns the search path (possibly after setting it)

`sf_proj_network` when called without arguments returns a logical indicating whether network search of datum grids is enabled, when called with arguments it returns a character vector with the URL of the CDN used (or specified with `url`).

`sf_proj_pipelines` returns a table with candidate coordinate transformation pipelines along with their accuracy; `NA` accuracy indicates ballpark accuracy.