/

SNAP Polarimetric Processing Sentinel-1

Runs a common polarimetric processing workflow with SNAP that operates ESA SAFE format scenes.


Description

A processing block that provides a SNAP polarimetric processing workflow that is applied on SAR scenes in the SAFE format.

See this block on the marketplace.

How it works

The SNAP block takes a Level 1C GRD image and generates a product ready for analysis by using a median filter for speckle filtering, creating a land-sea mask, and converting the image to the GeoTIFF format.

For each chosen polarization, a separate band will be generated in the output file. For instance, if both VV and VH polarizations are selected, the output will be a single GeoTIFF with two bands, one for VV and one for VH polarization.

ParameterOverview
bboxarray of integers / required if
Required if intersects or contains aren't specified.
A bounding box to use as an AOI. Will clip to scenes that intersect with this box.
containsobject / required if
Required if bbox or intersects aren't specified.
A GeoJSON geometry to use as an AOI. Will clip to scenes that fully cover this geometry.
intersectsobject / required if
Required if bbox or contains aren't specified.
A GeoJSON geometry to use as an AOI. Will clip to scenes that intersect with this geometry.
polarisationsarray of strings / required
Requested polarizations, vertical (V) or horizontal (H). The allowed values:
  • ["VV","VH"]
  • ["HH","HV"]
  • ["VV"]
  • ["VH"]
  • ["HV"]
  • ["HH"]
The default value is ["VV"]. If the requested polarization is not available in the input image to SNAP, the operation will fail and give a corresponding error message.
maskstring / required
A type of surface to apply the mask to. The allowed values:
  • land
  • sea
tcorrectionboolean / required
Whether to apply Range Doppler Terrain Correction based on a suitable Digital Elevation Model (DEM). The default value is true.
clip_to_aoiboolean / required
Whether the specified AOI should be clipped before processing:
  • true — The AOI should be clipped first.
  • false — The full scene should be processed.
The default value is false.
calibration_bandarray of strings / required
Applies calibration to provide imagery in which the pixel values can be directly related to the radar backscatter of the scene. The allowed values:
  • beta
  • gamma
  • sigma
The default value is sigma.
speckle_filterboolean / required
Whether to apply Lee Sigma filter to remove speckle noise from the image. The default value is true.
linear_to_dbboolean / required
Whether to convert the pixel intensity to normalized radar cross-section measured in decibel units. The default value is true.

Example

An example using the Sentinel-1 L1 GRD (SAFE) as a data source which is processed via SNAP after clipping it to the given AOI.

{
  "sobloo-s1-grd-fullscene:1": {
    "bbox": [13.358345031738283, 52.480689337378706, 13.395252227783203, 52.507654123207665],
    "ids": null,
    "time": "2018-01-01T00:00:00+00:00/2019-12-31T23:59:59+00:00",
    "limit": 1,
    "time_series": null,
    "orbit_direction": null,
    "acquisition_mode": null
  },
  "snap-polarimetric:1": {
    "bbox": [13.358345031738283, 52.480689337378706, 13.395252227783203, 52.507654123207665],
    "mask": null,
    "contains": null,
    "intersects": null,
    "clip_to_aoi": true,
    "tcorrection": true,
    "linear_to_db": true,
    "polarisations": ["VV"],
    "speckle_filter": true,
    "calibration_band": ["sigma"]
  }
}

Capabilities

Input

raster
up42_standard
bands
{
  "or": [
    [
      "HH",
      "HV",
      "alpha"
    ],
    [
      "VV",
      "VH",
      "alpha"
    ],
    [
      "HH",
      "alpha"
    ],
    [
      "VV",
      "alpha"
    ]
  ]
}
dtypeuint16
formatSAFE
sensorSentinel1GRD
resolution10
processing_levell1

Output

To know more please check the block capabilities specifications.