Add format creation method, and update tar_terra_rast()

.Rbuildignore

@@ -4,3 +4,10 @@
 ^\.github$
 ^codecov\.yml$
 ^LICENSE\.md$
+
+^_targets$
+^_targets_r$
+^_targets\.R$
+^_targets_packages\.R$
+^_targets\.Rmd$
+^_targets\.yaml$

.gitignore

@@ -4,3 +4,11 @@
 .httr-oauth
 .DS_Store
 .quarto
+.Rprofile
+
+_targets_packages.R
+_targets
+_targets.R
+_targets.Rmd
+_targets_r
+_targets.yaml

DESCRIPTION

@@ -14,6 +14,12 @@ Authors@R: c(
       family = "Scott",
       role = c("aut"),
       comment = c(ORCID = "0000-0002-7430-7879")
+    ),
+    person(
+      given = "Andrew",
+      family = "Brown",
+      role = c("aut"),
+      comment = c(ORCID = "0000-0002-4565-533X")
     )
     )
 Description: Provides extensions for various geospatial file formats, 
@@ -30,6 +36,8 @@ Imports:
     terra
 Suggests: 
     testthat (>= 3.0.0)
+Depends:
+    R (>= 4.1.0)
 Config/testthat/edition: 3
 URL: https://github.com/njtierney/geotargets
 BugReports: https://github.com/njtierney/geotargets/issues

NAMESPACE

@@ -1,3 +1,5 @@
 # Generated by roxygen2: do not edit by hand
 
+export(tar_terra_rast)
+export(tar_terra_vect)
 importFrom(utils,globalVariables)

R/tar-terra-rast.R

@@ -0,0 +1,138 @@
+#' Create a terra _SpatRaster_ Target
+#'
+#' Creates a target for a terra _SpatRaster_ object.
+#'
+#' @param name Character of length 1, name of the target.
+#' @param command An R expression. See `[targets::tar_target()]` for details
+#' @param pattern Language to define branching for a target. See `[targets::tar_target()]` for details.
+#' @param filetype character. File format expressed as GDAL driver names passed to `terra::writeRaster()`
+#' @param gdal character. GDAL driver specific datasource creation options passed to `terra::writeRaster()`
+#' @param ... Additional arguments not yet used
+#'
+#' @inheritParams targets::tar_target
+#'
+#' @seealso [targets::tar_target_raw()]
+#' @export
+#' @examples
+#' if (Sys.getenv("TAR_LONG_EXAMPLES") == "true") {
+#'  targets::tar_dir({ # tar_dir() runs code from a temporary directory.
+#'    library(geotargets)
+#'    targets::tar_script({
+#'      list(
+#'        geotargets::tar_terra_rast(
+#'          terra_rast_example,
+#'          system.file("ex/elev.tif", package = "terra") |> terra::rast()
+#'        )
+#'      )
+#'    })
+#'    targets::tar_make()
+#'    x <- targets::tar_read(terra_rast_example)
+#'  })
+#'}
+tar_terra_rast <- function(name,
+                           command,
+                           pattern = NULL,
+                           filetype = NULL,
+                           gdal = NULL,
+                           ...,
+                           tidy_eval = targets::tar_option_get("tidy_eval"),
+                           packages = targets::tar_option_get("packages"),
+                           library = targets::tar_option_get("library"),
+                           repository = targets::tar_option_get("repository"),
+                           iteration = targets::tar_option_get("iteration"),
+                           error = targets::tar_option_get("error"),
+                           memory = targets::tar_option_get("memory"),
+                           garbage_collection = targets::tar_option_get("garbage_collection"),
+                           deployment = targets::tar_option_get("deployment"),
+                           priority = targets::tar_option_get("priority"),
+                           resources = targets::tar_option_get("resources"),
+                           storage = targets::tar_option_get("storage"),
+                           retrieval = targets::tar_option_get("retrieval"),
+                           cue = targets::tar_option_get("cue")) {
+
+    name <- targets::tar_deparse_language(substitute(name))
+
+    envir <- targets::tar_option_get("envir")
+
+    command <- targets::tar_tidy_eval(
+        expr = as.expression(substitute(command)),
+        envir = envir,
+        tidy_eval = tidy_eval
+    )
+
+    pattern <- targets::tar_tidy_eval(
+        expr = as.expression(substitute(pattern)),
+        envir = envir,
+        tidy_eval = tidy_eval
+    )
+
+    # could pull defaults from geotargets package options
+    if (is.null(filetype)) {
+        filetype <- "GTiff"
+    }
+
+    if (is.null(gdal)) {
+        gdal <- "ENCODING=UTF-8"
+    }
+
+    targets::tar_target_raw(
+        name = name,
+        command = command,
+        pattern = pattern,
+        packages = packages,
+        library = library,
+        format = create_format_terra_raster(filetype = filetype, gdal = gdal, ...),
+        repository = repository,
+        iteration = iteration,
+        error = error,
+        memory = memory,
+        garbage_collection = garbage_collection,
+        deployment = deployment,
+        priority = priority,
+        resources = resources,
+        storage = storage,
+        retrieval = retrieval,
+        cue = cue
+    )
+}
+
+#' @param filetype File format expressed as GDAL driver names passed to `terra::writeRaster()`
+#' @param gdal GDAL driver specific datasource creation options passed to `terra::writeRaster()`
+#' @param ... Additional arguments not yet used
+#' @noRd
+create_format_terra_raster <- function(filetype, gdal, ...) {
+
+    if (!requireNamespace("terra")) {
+        stop("package 'terra' is required", call. = FALSE)
+    }
+
+    # get list of drivers available for writing depending on what the user's GDAL supports
+    drv <- terra::gdal(drivers = TRUE)
+    drv <- drv[drv$type == "raster" & grepl("write", drv$can), ]
+
+    filetype <- match.arg(filetype, drv$name)
+
+    if (is.null(filetype)) {
+        filetype <- "GTiff"
+    }
+
+    .write_terra_raster <- function(object, path) {
+        terra::writeRaster(
+            object,
+            path,
+            filetype = NULL,
+            overwrite = TRUE,
+            gdal = NULL
+        )
+    }
+    body(.write_terra_raster)[[2]][["filetype"]] <- filetype
+    body(.write_terra_raster)[[2]][["gdal"]] <- gdal
+
+    targets::tar_format(
+        read = function(path) terra::rast(path),
+        write = .write_terra_raster,
+        marshal = function(object) terra::wrap(object),
+        unmarshal = function(object) terra::unwrap(object)
+    )
+}
+