R: Functions to instantiate a new cube from a source

source_cube {sits} | R Documentation

## Functions to instantiate a new cube from a source

### Description

These functions provide an API to instantiate a new cube object and access/retrieve information from services or local files to fill cube attributes.

A cube is formed by images (items) organized in tiles. To create a sits cube object (a `tibble`), a set of functions are called in order to retrieve metadata.

`.source_cube()` is called to start the cube creation from a source.

`.source_item_get_date()` retrieves the date of an item (a set of images from different bands that forms a scene).

`.source_item_get_hrefs()` retrieves the paths or URLs of each file bands of an item.

`.source_item_get_bands()` retrieves the bands present in an item.

`.source_item_get_resolution()` retrieves the supported resolution of an item (for each band).

`.source_items_new()` this function is called to create an items object. In case of Web services, this function is responsible for making the Web requests to the server.

`.source_items_fileinfo()` creates the `fileinfo` specification from items object.

`.source_items_tiles_group()` organizes items by tiles and arrange items in each tile by date.

`.source_items_get_sensor()` retrieves the sensor from items object.

`.source_items_get_satellite()` retrieves the satellite name (platform) from items object.

`.source_items_tile_get_crs()` retrieves the CRS string from items.

`.source_items_tile_get_name()` retrieves the tile name from items.

`.source_items_tile_get_bbox()` retrieves the bounding box from items of a tile.

`.source_itimes_cube()` is called to create a data cubes tile, that is, a row in sits data cube.

### Usage

    .source_cube(source, ..., collection)

    .source_item_get_date(source, ..., item, collection = NULL)

    .source_item_get_hrefs(source, ..., item, collection = NULL)

    .source_item_get_bands(source, ..., item, collection = NULL)

    .source_item_get_resolution(source, ..., item, collection = NULL)

    .source_items_new(source, ..., collection)

    .source_items_bands_select(source, ..., collection, items, bands)

    .source_items_fileinfo(source, ..., items, collection = NULL)

    .source_items_tiles_group(source, ..., items, collection = NULL)

    .source_collection_sensor(source, collection)

    .source_collection_satellite(source, collection)

    .source_items_tile_get_crs(source, ..., tile_items, collection = NULL)

    .source_items_tile_get_name(source, ..., tile_items, collection = NULL)

    .source_items_tile_get_bbox(source, ..., tile_items, collection = NULL)

    .source_items_cube(source, ..., collection, items, file_info)

### Arguments

`source` | A `character` value referring to a valid data source.
`...` | Additional parameters.
`collection` | A `character` value referring to a collection of the source.
`items` | Any object referring to the images bands (scenes) that compose a cube.
`bands` | Bands to be selected in the collection.
`file_info` | A `tibble` that organizes the metadata about each file in the tile: date, band, resolution, and path (or URL).
`data_dir` | Directory where local files are stored

### Value

The values returned by each function are described as follows.

`.source_cube()` returns a sits `tibble` with cube metadata.

`.source_item_get_date()` returns a `Date` value.

`.source_item_get_hrefs()` returns a `character` vector containing paths to each image band of an item.

`.source_item_get_bands()` returns a `character` vector containing bands name of an item.

`.source_item_get_resolution()` returns a named `list` with `numeric` vectors containing the supported resolution for each band

`.source_items_new()` returns any object referring the images of a sits cube.

A `STACItemCollection` object returned by rstac with items selected.

`.source_items_bands_select()` returns the same object as `items` with selected bands.

`.source_items_fileinfo()` returns a `tibble` containing sits cube.

`.source_items_tiles_group()` returns a `list` of items.

`.source_items_get_sensor()` returns a `character` value.

`.source_items_get_satellite()` returns a `character` value.

`.source_items_tile_get_crs()` returns a `character` value.

`.source_items_tile_get_name()` returns a `character` value.

`.source_items_tile_get_bbox()` returns a `numeric` vector with 4 elements (xmin, ymin, xmax, ymax).

`.source_items_cube()` returns a `tibble` containing a sits cube tile (one row).

[Package sits version 0.15.1 Index]