reduce_dimension.json

{
    "id": "reduce_dimension",
    "summary": "Reduce dimensions",
    "description": "Applies a unary reducer to a data cube dimension by collapsing all the pixel values along the specified dimension into an output value computed by the reducer. This process passes a list of values to the reducer. In contrast, ``reduce_dimension_binary()`` passes two values, which may be better suited especially for UDFs in case the number of values gets too large to be processed at once.\n\nThe dimension is dropped. To avoid this, use ``apply_dimension()`` instead.",
    "categories": [
        "cubes",
        "reducer"
    ],
    "parameters": [
        {
            "name": "data",
            "description": "A data cube.",
            "schema": {
                "type": "object",
                "subtype": "raster-cube"
            }
        },
        {
            "name": "reducer",
            "description": "A reducer to apply on the specified dimension. A reducer is a single process such as ``mean()`` or a set of processes, which computes a single value for a list of values, see the category 'reducer' for such processes.",
            "schema": {
                "type": "object",
                "subtype": "process-graph",
                "parameters": [
                    {
                        "name": "data",
                        "description": "A labeled array with elements of any type.",
                        "schema": {
                            "type": "array",
                            "subtype": "labeled-array",
                            "items": {
                                "description": "Any data type."
                            }
                        }
                    },
                    {
                        "name": "context",
                        "description": "Additional data passed by the user.",
                        "schema": {
                            "description": "Any data type."
                        },
                        "optional": true,
                        "default": null
                    }
                ]
            }
        },
        {
            "name": "dimension",
            "description": "The name of the dimension over which to reduce. Fails with a `DimensionNotAvailable` error if the specified dimension does not exist.\n\n**Remarks:**\n\n* The default dimensions a data cube provides are described in the collection's metadata field `cube:dimensions`.\n* There could be multiple spatial dimensions such as `x`, `y` or `z`.\n* For multi-spectral imagery there is usually a separate dimension of type `bands` for the bands.",
            "schema": {
                "type": "string"
            }
        },
        {
            "name": "context",
            "description": "Additional data to be passed to the reducer.",
            "schema": {
                "description": "Any data type."
            },
            "optional": true,
            "default": null
        }
    ],
    "returns": {
        "description": "A data cube with the newly computed values. It has one dimension less than the original data cube, but the remaining dimensions have their resolution and cardinality preserved.",
        "schema": {
            "type": "object",
            "subtype": "raster-cube"
        }
    },
    "exceptions": {
        "DimensionNotAvailable": {
            "message": "A dimension with the specified name does not exist."
        }
    }
}