Statistical info API documentation

The Statistical info (or feature info service, abbreviated FIS), performs elementary statistical computations---such as mean, standard deviation, and histogram approximating the distribution of reflectance values---on remotely sensed data for a region specified in a given spatial reference system across different bands and time ranges.

A quintessential usage example would be querying the service for basic statistics and the distribution of NDVI values for a polygon representing an agricultural unit over a time range.

Basic information

The service retrieves all data from the given time range that fit the prescribed criteria, computes statistics on these data, and returns the result in the form of a JSON object.

The base URL for the FIS service: http://services.sentinel-hub.com/ogc/fis/{INSTANCE_ID}. Replace {INSTANCE_ID} with the one you find in the WMS Configurator (as in examples of query URLs at the bottom of the page).

By deafult, the service uses the settings from the instance specified by the instance ID, but one can override these by specifying them in the URL. For example, setting MAXCC=10 overrides whatever is set in the instance settings in the WMS configurator. The instances are managed (i.e. edited, created, and deleted) in the Configuration Utility.

FIS only works on instances that don't enforce image types other than 32 bit RAW. Ensure that the image type is not enforced in the instance configuration (i.e. either have it set to None or to image/raw;depth=32f).

As of this writing, only GET endpoint is implemented.  

More details

More about custom URL parameters, output image formats, atmospheric correction, preview modes, custom evaluation script, and which operations can be used with WMS, WMTS, WFS or WCS services is available here.

FIS URL parameters

Below is a list of FIS parameters. Besides these, one can also pass custom parameters.

*Note. One should use either BBOX or GEOMETRY, never both, to specify the region of interest.

For more information about layers and styles, see the WMS documentation.

Output format

The service works on single-band (e.g., NDVI, NDWI, etc.) as well as multi-band (e.g., TRUE_COLOR, FALSE_COLOR, etc.) products. In case of a multi-band product, the statistics are computed for each band (see the description of the output structure below).

Results are always returned as JSON objects of the following form:

{
	"C0": [
		{
			"date": "date1",
			"basicStats": {
				"min": minValue1,
				"max": maxValue1,
				"mean": meanValue1,
				"stDev": standardDeviation1,
			},
			"histogram": [
				{
					"value": value,
					"count": count
				},
				...,
				{
					"value": value,
					"count": count
				},
			]
		},
		...,
		{
			...
		}
	],
	...,
	"CN": [
		...
	]
}
			

In words, the bands comprising the specified layer correspond to keys in the response JSON object. The value associated with each band is an array of objects containing statistics for that band in the image, one per available date.

The "histogram" is absent when the histogram isn't request (i.e., when the BINS parameter is not set).

Examples

The example below illustrates how data from the statistical service may be visualized.

Visualizing the results

Below is a plot of NDVI value distributions across time ranges. The violin plots were computed from the following FIS request: http://services.sentinel-hub.com/ogc/fis/{INSTANCE_ID}?LAYER=5_VEGETATION_INDEX&STYLE=INDEX&CRS=EPSG%3A3857&

TIME=2015-01-01%2F2015-10-01&BBOX=1550369.86,5586056.25,1547498.69,5584861.92&RESOLUTION=10&MAXCC=5&BINS=100

Requesting stats without a histogram

Query URL: http://services.sentinel-hub.com/ogc/fis/{INSTANCE_ID}?LAYER=5_VEGETATION_INDEX&STYLE=INDEX&CRS=EPSG%3A3857&TIME=2015-01-01%2

F2015-10-01&BBOX=1550369.86,5586056.25,1547498.69,5584861.92&RESOLUTION=10&MAXCC=5

Response:

{
  "C0": [
    {
      "date": "2015-08-30",
      "basicStats": {
        "min": -0.5478424429893494,
        "max": 0.7815912365913391,
        "mean": 0.147320137875888,
        "stDev": 0.35443419609590726
      }
    },
    {
      "date": "2015-07-11",
      "basicStats": {
        "min": -0.5127978920936584,
        "max": 0.8115044236183167,
        "mean": 0.20168528533031557,
        "stDev": 0.31436594348376923
      }
    }
  ]
}

Requesting stats with a histogram

Query URL: http://services.sentinel-hub.com/ogc/fis/{INSTANCE_ID}?LAYER=5_VEGETATION_INDEX&STYLE=INDEX&CRS=EPSG%3A3857&TIME=2015-01-01%2

F2015-10-01&BBOX=1550369.86,5586056.25,1547498.69,5584861.92&RESOLUTION=10&MAXCC=5&BINS=5

Response:

{
  "C0": [
    {
      "date": "2015-08-30",
      "basicStats": {
        "min": -0.5478424429893494,
        "max": 0.7815912365913391,
        "mean": 0.147320137875888,
        "stDev": 0.35443419609590726
      },
      "histogram": {
        "bins": [
          {
            "value": -0.23164855383139124,
            "count": 14377.0
          },
          {
            "value": 0.08134964140017291,
            "count": 1844.0
          },
          {
            "value": 0.23792375711536012,
            "count": 4692.0
          },
          {
            "value": 0.37365802377462387,
            "count": 4.0
          },
          {
            "value": 0.5359620948992795,
            "count": 13236.0
          }
        ]
      }
    },
    {
      "date": "2015-07-11",
      "basicStats": {
        "min": -0.5127978920936584,
        "max": 0.8115044236183167,
        "mean": 0.20168528533031557,
        "stDev": 0.31436594348376923
      },
      "histogram": {
        "bins": [
          {
            "value": -0.3067768962218847,
            "count": 145.0
          },
          {
            "value": -0.11833351501876165,
            "count": 14484.0
          },
          {
            "value": 0.13131743694345155,
            "count": 30.0
          },
          {
            "value": 0.24965114950902842,
            "count": 7984.0
          },
          {
            "value": 0.5777060477812307,
            "count": 11510.0
          }
        ]
      }
    }
  ]
}