R: Read a data cube from a json description file

json_cube {gdalcubes} | R Documentation

## Read a data cube from a json description file

### Description

Read a data cube from a json description file

### Usage

    json_cube(json, path = NULL)

### Arguments

`json` | length-one character vector with a valid json data cube description
`path` | source data cube proxy object

### Details

Data cubes can be stored as JSON description files. These files do not store any data but the recipe how a data cube is consructed, i.e., the chain (or graph) of processes involved.

Since data cube objects (as returned from `raster_cube`) cannot be saved with normal R methods, the combination of `as_json` and `json_cube` provides a cheap way to save data cube objects across several R sessions, as in the examples.

### Value

data cube proxy object

### Examples

    {
    # create image collection from example Landsat data only
    # if not already done in other examples
    if (!file.exists(file.path(tempdir(), "L8.db"))) {
      L8_files <- list.files(system.file("L8NY18", package = "gdalcubes"),
                             ".TIF", recursive = TRUE, full.names = TRUE)
      create_image_collection(L8_files, "L8_L1TP", file.path(tempdir(), "L8.db"))
    }

    L8.col = image_collection(file.path(tempdir(), "L8.db"))
    v = cube_view(extent=list(left=388941.2, right=766552.4,
                  bottom=4345299, top=4744931, t0="2018-01", t1="2018-12"),
                  srs="EPSG:32618", nx = 497, ny=526, dt="P1M")
    cube = raster_cube(L8.col, v)

    # save
    fname = tempfile()
    writeLines(as_json(cube), fname)

    # load
    json_cube(path = fname)
    }

[Package gdalcubes version 0.6.0 Index]