as_json

Query data cube properties

Description

gdalcubes internally uses a graph to serialize data cubes (including chained operations on cubes). This function derives a JSON representation, which can be used to save data cube objects without pixel data to disk.

Usage

as_json(obj, file = NULL)

Arguments

Argument Description
obj a data cube proxy object (class cube)
file optional output file

Value

If file is NULL, the function returns a JSON string representing a graph that can be used to recreate the same chain of gdalcubes operations even in a different R sessions.

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"), quiet = TRUE) 
}

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="2018-04", t1="2018-04"),
              srs="EPSG:32618", nx = 497, ny=526, dt="P1M")
cat(as_json(select_bands(raster_cube(L8.col, v), c("B04", "B05"))))
{
    "bands": [
        "B04",
        "B05"
    ],
    "cube_type": "select_bands",
    "in_cube": {
        "chunk_size": [
            1,
            384,
            384
        ],
        "cube_type": "image_collection",
        "file": "/tmp/RtmptGkYB2/L8.db",
        "view": {
            "aggregation": "first",
            "resampling": "near",
            "space": {
                "bottom": 4345299,
                "left": 388941.20000000001,
                "nx": 497,
                "ny": 526,
                "right": 766552.40000000002,
                "srs": "EPSG:32618",
                "top": 4744931
            },
            "time": {
                "dt": "P1M",
                "t0": "2018-04-01",
                "t1": "2018-04-30"
            }
        }
    }
}