items_group | R Documentation |
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 the datetime
field in properties
from STACItemCollection
and
STACItem
objects.
items_bbox()
: retrieves the bbox
field of a STACItemCollection
or a STACItem
object.
item_assets()
: returns the assets name from
STACItemCollection
and STACItem
objects.
items_filter()
: selects only items that match some criteria
(see details section).
items_reap()
: extract key values by traversing all items
in a 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.
items_group(items, ..., field = NULL, index = NULL)
items_length(items)
## S3 method for class 'STACItem'
items_length(items)
## S3 method for class 'STACItemCollection'
items_length(items)
## Default S3 method:
items_length(items)
items_matched(items, matched_field = NULL)
## S3 method for class 'STACItem'
items_matched(items, matched_field = NULL)
## S3 method for class 'STACItemCollection'
items_matched(items, matched_field = NULL)
## Default S3 method:
items_matched(items, matched_field = NULL)
items_fetch(items, ...)
## S3 method for class 'STACItemCollection'
items_fetch(items, ..., progress = TRUE, matched_field = NULL)
items_next(items, ...)
## S3 method for class 'STACItemCollection'
items_next(items, ...)
items_datetime(items)
## S3 method for class 'STACItem'
items_datetime(items)
## S3 method for class 'STACItemCollection'
items_datetime(items)
## Default S3 method:
items_datetime(items)
items_bbox(items)
## S3 method for class 'STACItem'
items_bbox(items)
## S3 method for class 'STACItemCollection'
items_bbox(items)
## Default S3 method:
items_bbox(items)
items_assets(items, simplify = deprecated())
## S3 method for class 'STACItem'
items_assets(items, simplify = deprecated())
## S3 method for class 'STACItemCollection'
items_assets(items, simplify = deprecated())
## Default S3 method:
items_assets(items, simplify = deprecated())
items_filter(items, ..., filter_fn = NULL)
## S3 method for class 'STACItemCollection'
items_filter(items, ..., filter_fn = NULL)
items_compact(items)
## S3 method for class 'STACItemCollection'
items_compact(items)
items_reap(items, field, ..., pick_fn = identity)
## S3 method for class 'STACItem'
items_reap(items, field, ..., pick_fn = identity)
## S3 method for class 'STACItemCollection'
items_reap(items, field, ..., pick_fn = identity)
## Default S3 method:
items_reap(items, field, ..., pick_fn = identity)
items_fields(items, field = NULL, ...)
## S3 method for class 'STACItem'
items_fields(items, field = NULL, ...)
## S3 method for class 'STACItemCollection'
items_fields(items, field = NULL, ...)
## Default S3 method:
items_fields(items, field = NULL, ...)
items_sign(items, sign_fn)
## S3 method for class 'STACItem'
items_sign(items, sign_fn)
## S3 method for class 'STACItemCollection'
items_sign(items, sign_fn)
## Default S3 method:
items_sign(items, sign_fn)
items_as_sf(items)
## S3 method for class 'STACItem'
items_as_sf(items)
## S3 method for class 'STACItemCollection'
items_as_sf(items)
items |
a |
... |
additional arguments. See details. |
field |
a |
index |
an |
matched_field |
a |
progress |
a |
simplify |
|
filter_fn |
a |
pick_fn |
a |
sign_fn |
a |
Ellipsis argument (...
) appears in different items functions 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_fields()
: ellipsis parameter is deprecated in version
0.9.2 of rstac. Please, use field
parameter instead.
items_filter()
: ellipsis is used to pass logical
expressions to be evaluated against a STACItem
field as filter criteria.
WARNING: the evaluation of filter expressions changed in rstac
0.9.2.
Older versions of rstac
used properties
field to evaluate filter
expressions. Below, there is an example of how to write expressions in new
rstac
version:
# expression in older version items_filter(stac_obj, `eo:cloud_cover` < 10) # now expressions must refer to properties explicitly items_filter(stac_obj, properties$`eo:cloud_cover` < 10) items_filter(stac_obj, properties[["eo:cloud_cover"]] < 10)
items_sign()
: in the near future, ellipsis will be used to append
key-value pairs to the 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 a signed item. rstac
provides
sign_bdc()
and sign_planetary_computer()
functions to access Brazil
Data Cube products and Microsoft Planetary Computer catalogs, respectively.
items_length()
: an integer
value.
items_matched()
: returns an integer
value if the STAC web server
does support this extension. Otherwise returns NULL
.
items_fetch()
: a 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()
: Returns a character
value with all assets names
of the all items.
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.
items_as_sf()
: a sf
object.
## Not run:
x <- stac("https://brazildatacube.dpi.inpe.br/stac") %>%
stac_search(collections = "CB4-16D-2") %>%
stac_search(limit = 500) %>%
get_request()
x %>% items_length()
x %>% items_matched()
x %>% items_datetime()
x %>% items_bbox()
x %>% items_fetch()
## End(Not run)
## Not run:
# Defining BDC token
Sys.setenv("BDC_ACCESS_KEY" = "token-123")
# STACItem object
stac("https://brazildatacube.dpi.inpe.br/stac/") %>%
stac_search(collections = "CB4-16D-2", limit = 100,
datetime = "2017-08-01/2018-03-01",
bbox = c(-48.206, -14.195, -45.067, -12.272)) %>%
get_request() %>% items_sign(sign_fn = sign_bdc())
## End(Not run)
## Not run:
# STACItemCollection object
stac("https://brazildatacube.dpi.inpe.br/stac/") %>%
stac_search(collections = "CB4-16D-2", limit = 100,
datetime = "2017-08-01/2018-03-01",
bbox = c(-48.206, -14.195, -45.067, -12.272)) %>%
get_request() %>%
items_filter(properties$`eo:cloud_cover` < 10)
# Example with AWS STAC
stac("https://earth-search.aws.element84.com/v0") %>%
stac_search(collections = "sentinel-s2-l2a-cogs",
bbox = c(-48.206, -14.195, -45.067, -12.272),
datetime = "2018-06-01/2018-06-30",
limit = 500) %>%
post_request() %>%
items_filter(filter_fn = function(x) {x$properties$`eo:cloud_cover` < 10})
## End(Not run)
## Not run:
# STACItemCollection object
stac_item <- stac("https://brazildatacube.dpi.inpe.br/stac/") %>%
stac_search(collections = "CB4-16D-2", limit = 100,
datetime = "2017-08-01/2018-03-01",
bbox = c(-48.206, -14.195, -45.067, -12.272)) %>%
get_request() %>% items_fetch(progress = FALSE)
stac_item %>% items_reap(field = c("properties", "datetime"))
## End(Not run)
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