normalized_difference.json

{
    "id": "normalized_difference",
    "summary": "Normalized difference",
    "description": "Computes the normalized difference for two bands. The normalized difference is computed as *`(x - y) / (x + y)`*.\n\nThis process could be used for a number of remote sensing indices such as:\n\n* [NDVI](https://eos.com/ndvi/): `x` = NIR band, `y` = red band\n* [NDWI](https://eos.com/ndwi/): `x` = NIR band, `y` = SWIR band\n* [NDSI](https://eos.com/ndsi/): `x` = green band, `y` = SWIR band\n\nSome back-ends may have native processes such as ``ndvi()`` available for convenience.",
    "categories": [
        "math > indices",
        "vegetation indices"
    ],
    "parameters": [
        {
            "name": "x",
            "description": "The value for the first band.",
            "schema": {
                "type": "number"
            }
        },
        {
            "name": "y",
            "description": "The value for the second band.",
            "schema": {
                "type": "number"
            }
        }
    ],
    "returns": {
        "description": "The computed normalized difference.",
        "schema": {
            "type": "number",
            "minimum": -1,
            "maximum": 1
        }
    },
    "links": [
        {
            "rel": "related",
            "href": "https://eos.com/ndvi/",
            "title": "NDVI explained by EOS"
        },
        {
            "rel": "related",
            "href": "https://eos.com/ndwi/",
            "title": "NDWI explained by EOS"
        },
        {
            "rel": "related",
            "href": "https://eos.com/ndsi/",
            "title": "NDSI explained by EOS"
        }
    ],
    "process_graph": {
        "subtract": {
            "process_id": "subtract",
            "arguments": {
                "x": {
                    "from_parameter": "x"
                },
                "y": {
                    "from_parameter": "y"
                }
            }
        },
        "add": {
            "process_id": "add",
            "arguments": {
                "x": {
                    "from_parameter": "x"
                },
                "y": {
                    "from_parameter": "y"
                }
            }
        },
        "divide": {
            "process_id": "divide",
            "arguments": {
                "x": {
                    "from_node": "subtract"
                },
                "y": {
                    "from_node": "add"
                }
            },
            "result": true
        }
    }
}