Create STAC items, properties, and assets — item

Pure builders for the building blocks of a STAC Item. None touch disk; use stac_save() to persist.

new_properties(): assembles an item properties list.
new_asset(): creates a single STAC Asset.
new_item(): creates an in-memory Item (a GeoJSON Feature).
add_items(): links one or more items into a collection, updating the collection links and spatio-temporal extent, and returns the collection.

STAC requires every item to carry a datetime. When you describe a time range instead of a single instant, supply start_datetime and end_datetime and omit datetime; new_properties() then records datetime as null, as the specification mandates. add_items() derives the collection's temporal extent from the range (or from datetime when only that is given).

Usage

new_properties(
  description = NULL,
  datetime = NULL,
  start_datetime = NULL,
  end_datetime = NULL,
  start_date = NULL,
  end_date = NULL,
  ...
)

new_asset(href, title = NULL, roles = list("data"), ...)

new_item(
  id,
  bbox,
  geometry = NULL,
  properties = new_properties(),
  assets = list(),
  collection = NULL,
  stac_version = "1.0.0",
  ...
)

add_items(collection, items)

Arguments

description: A character description.
datetime: A character RFC 3339 datetime, or NULL. Recorded as null when omitted alongside a start_datetime/end_datetime range.
start_datetime: A character RFC 3339 start datetime, or NULL.
end_datetime: A character RFC 3339 end datetime, or NULL.
start_date: A character start date, or NULL.
end_date: A character end date, or NULL.
...: Additional named fields. See details for each function.
href: A character asset target (path or URL).
title: A character title.
roles: A list of asset roles. Defaults to list("data").
id: A character identifier for the item.
bbox: A numeric vector c(xmin, ymin, xmax, ymax).
geometry: A GeoJSON geometry list. If NULL, it is derived from bbox via as_geometry().
properties: A list of item properties, e.g. from new_properties().
assets: A named list of assets, e.g. from new_asset().
collection: For add_items(), the doc_collection to link items into. For new_item(), an optional doc_collection or character collection id recorded as the item's top-level collection field. STAC requires this field whenever the item carries a collection link (as items built here always do); when omitted, stac_save() stamps it from the collection it is given.
stac_version: A character STAC version. Defaults to "1.0.0".
items: A single doc_item, or a list of doc_item objects, to link into the collection.

Value

new_properties(): a list of properties.
new_asset(): a doc_asset object describing an asset.
new_item(): a doc_item object.
add_items(): the updated doc_collection.

Examples

props <- new_properties(datetime = "2020-01-01T00:00:00Z")
asset <- new_asset("data.tif", title = "Data")
item <- new_item(
  id = "item-1",
  bbox = c(-50, -10, -49, -9),
  properties = props,
  assets = list(data = asset)
)
item$type
#> [1] "Feature"

col <- new_collection("col", "Collection", "Example")
col <- add_items(col, item)
col$extent$spatial$bbox[[1]]
#> [1] -50 -10 -49  -9