These functions provide support to work with
STACItemCollection and STACItem objects.
items_length(): shows how many items there are in
the STACItemCollection object.
items_matched(): shows how many items matched the
search criteria. It supports search:metadata (v0.8.0),
context (v0.9.0), and numberMatched (OGC WFS3 core spec).
items_fetch(): request all STAC Items through
pagination.
items_next(): fetches a new page from STAC service.
items_datetime(): retrieves a the datetime
field in properties from STACItemCollection and
STACItem objects.
items_bbox(): retrieves a the bbox
field of a STACItemCollection or an STACItem object.
item_assets(): returns the assets name from
STACItemCollection and STACItem objects.
items_filter(): selects only items that match some
criteria.
items_reap(): extract key values by traversing all items
in an STACItemCollection object.
items_fields(): lists field names inside an item.
items_group(): organizes items as elements of a list using
some criteria.
items_sign(): allow access assets by preparing its url.
This function returns the subfields of the feature
field of a STACItemCollection object.
items_length(items)# S3 method for STACItem
items_length(items)
# S3 method for STACItemCollection
items_length(items)
items_matched(items, ...)
# S3 method for STACItem
items_matched(items, ...)
# S3 method for STACItemCollection
items_matched(items, ..., matched_field = NULL)
items_fetch(items, ...)
# S3 method for STACItem
items_fetch(items, ...)
# S3 method for STACItemCollection
items_fetch(items, ..., progress = TRUE, matched_field = NULL)
items_next(items, ...)
# S3 method for STACItem
items_next(items, ...)
# S3 method for STACItemCollection
items_next(items, ...)
items_datetime(items)
# S3 method for STACItem
items_datetime(items)
# S3 method for STACItemCollection
items_datetime(items)
items_bbox(items)
# S3 method for STACItem
items_bbox(items)
# S3 method for STACItemCollection
items_bbox(items)
items_assets(items, ...)
# S3 method for STACItem
items_assets(items, ...)
# S3 method for STACItemCollection
items_assets(items, ..., simplify = FALSE)
items_filter(items, ..., filter_fn = NULL)
items_reap(items, ..., field = NULL)
items_fields(items, ..., field = NULL)
# S3 method for STACItemCollection
items_fields(items, ..., field = NULL)
# S3 method for STACItem
items_fields(items, ..., field = NULL)
items_group(items, ..., field = NULL, index = NULL)
items_sign(items, ..., sign_fn = NULL)
# S3 method for STACItemCollection
items_sign(items, ..., sign_fn = NULL)
# S3 method for STACItem
items_sign(items, ..., sign_fn = NULL)
items_length(): an integer value.
items_matched(): returns an integer value if STAC web server does
support this extension, otherwise returns NULL.
items_fetch(): an STACItemCollection with all matched items.
items_next(): fetches a new page from STAC service.
items_datetime(): a list of all items' datetime.
items_bbox(): returns a list with all items' bounding boxes.
item_assets(): if simplify is TRUE, returns a character
value with all assets names of the first item. Otherwise, returns a
list with assets name for each item.
items_filter(): a STACItemCollection object.
items_reap(): a vector if the supplied field is atomic,
otherwise or a list.
items_fields(): a character vector.
items_group(): a list of STACItemCollection objects.
items_sign(): a STACItemCollection object with signed assets url
A character with the subfields of the feature field.
a STACItemCollection object representing
the result of /stac/search, /collections/{collectionId}/items.
a named way to provide field names to get the subfields values
from the RSTACDocument objects.
a character vector with the path
where the number of items returned in the named list is located starting from
the initial node of the list. For example, if the information is at position
items$meta$found of the object, it must be passed as the following
parameter c("meta", "found").
a logical indicating if a progress bar must be
shown or not. Defaults to TRUE.
a logical should return only the assets name of the
first item? if not a list with all assets name will be returned. Default
is FALSE.
a function that receives an item that should
evaluate a logical value.
a character with the names of the field to get the
subfields values from the RSTACDocument objects.
an atomic vector with values as group index
a function that receives an item as parameter
and returns an item signed.
Ellipsis argument (...) appears in different items function and
has distinct purposes:
items_matched() and items_assets(): ellipsis is not used.
items_fetch() and items_next(): ellipsis is used to pass
additional httr options to GET or POST
methods, such as add_headers or
set_cookies.
items_filter(): ellipsis is used to pass logical
expressions using keys in properties field as filter criteria.
items_reap(), items_fields(), and items_group(): ellipsis can
be used to provide fields names to get the subfields values from
the STACItemCollection objects.
items_sign(): in a near future, ellipsis will be used to append
key value pairs to url query string of an asset.
items_sign() has sign_fn parameter that must be a function that
receives as argument an item and returns an signed item. rstac provides
sign_bdc() and sign_planetary_computer() functions to access Brazil
Data Cube products and Microsoft Planetary Computer catalogs, respectively.