SAR calibration

SAR Calibration¶

Create a graph to calibrate a Sentinel-1 GRD product

In [1]:

from snapista import Graph
from snapista import Operator, OperatorParams

Create a Graph object

In [2]:

g = Graph()

Add the Read node to the graph

In [3]:

path_to_manifest = 'path to manifest'

g.add_node(
    operator=Operator(
        "Read",
        formatName="SENTINEL-1",
        file=path_to_manifest,
    ),
    node_id="read",
)

Add the remaining nodes:

In [4]:

g.add_node(
        operator=Operator("Apply-Orbit-File", continueOnFail="true"),
        node_id="apply-orbit-file",
        source="read",
)

g.add_node(
    operator=Operator(
        "Remove-GRD-Border-Noise", borderLimit="2000", trimThreshold="0.2"
    ),
    node_id="noise-removal",
    source="apply-orbit-file",
)

g.add_node(
    operator=Operator("Calibration"),
    node_id="calibration",
    source="noise-removal",
)

g.add_node(
    operator=Operator("LinearToFromdB"),
    node_id="linear",
    source="calibration",
)

g.add_node(
    operator=Operator(
        "Terrain-Correction",
        pixelSpacingInMeter="20.0",
        demName="SRTM 3Sec",
        mapProjection="AUTO:42001",
        ),
        node_id="terrain-correction",
        source="linear",
)

g.add_node(
    operator=Operator("Write", file='result.tif', formatName="GeoTIFF-BigTIFF"),
    node_id="write",
    source="terrain-correction",
)

Inspect the graph

In [5]:

g.view()

<graph>
  <version>1.0</version>
  <node id="read">
    <operator>Read</operator>
    <sources/>
    <parameters class="com.bc.ceres.binding.dom.XppDomElement">
      <bandNames/>
      <copyMetadata>true</copyMetadata>
      <file>path to manifest</file>
      <formatName>SENTINEL-1</formatName>
      <geometryRegion/>
      <maskNames/>
      <pixelRegion/>
    </parameters>
  </node>
  <node id="apply-orbit-file">
    <operator>Apply-Orbit-File</operator>
    <sources>
      <sourceProduct refid="read"/>
    </sources>
    <parameters class="com.bc.ceres.binding.dom.XppDomElement">
      <continueOnFail>true</continueOnFail>
      <orbitType>Sentinel Precise (Auto Download)</orbitType>
      <polyDegree>3</polyDegree>
    </parameters>
  </node>
  <node id="noise-removal">
    <operator>Remove-GRD-Border-Noise</operator>
    <sources>
      <sourceProduct refid="apply-orbit-file"/>
    </sources>
    <parameters class="com.bc.ceres.binding.dom.XppDomElement">
      <borderLimit>2000</borderLimit>
      <selectedPolarisations/>
      <trimThreshold>0.2</trimThreshold>
    </parameters>
  </node>
  <node id="calibration">
    <operator>Calibration</operator>
    <sources>
      <sourceProduct refid="noise-removal"/>
    </sources>
    <parameters class="com.bc.ceres.binding.dom.XppDomElement">
      <auxFile>Latest Auxiliary File</auxFile>
      <createBetaBand>false</createBetaBand>
      <createGammaBand>false</createGammaBand>
      <externalAuxFile/>
      <outputBetaBand>false</outputBetaBand>
      <outputGammaBand>false</outputGammaBand>
      <outputImageInComplex>false</outputImageInComplex>
      <outputImageScaleInDb>false</outputImageScaleInDb>
      <outputSigmaBand>true</outputSigmaBand>
      <selectedPolarisations/>
      <sourceBandNames/>
    </parameters>
  </node>
  <node id="linear">
    <operator>LinearToFromdB</operator>
    <sources>
      <sourceProduct refid="calibration"/>
    </sources>
    <parameters class="com.bc.ceres.binding.dom.XppDomElement">
      <sourceBandNames/>
    </parameters>
  </node>
  <node id="terrain-correction">
    <operator>Terrain-Correction</operator>
    <sources>
      <sourceProduct refid="linear"/>
    </sources>
    <parameters class="com.bc.ceres.binding.dom.XppDomElement">
      <alignToStandardGrid>false</alignToStandardGrid>
      <applyRadiometricNormalization>false</applyRadiometricNormalization>
      <auxFile>Latest Auxiliary File</auxFile>
      <demName>SRTM 3Sec</demName>
      <demResamplingMethod>BILINEAR_INTERPOLATION</demResamplingMethod>
      <externalAuxFile/>
      <externalDEMApplyEGM>true</externalDEMApplyEGM>
      <externalDEMFile/>
      <externalDEMNoDataValue>0</externalDEMNoDataValue>
      <imgResamplingMethod>BILINEAR_INTERPOLATION</imgResamplingMethod>
      <incidenceAngleForGamma0>Use projected local incidence angle from DEM</incidenceAngleForGamma0>
      <incidenceAngleForSigma0>Use projected local incidence angle from DEM</incidenceAngleForSigma0>
      <mapProjection>AUTO:42001</mapProjection>
      <nodataValueAtSea>true</nodataValueAtSea>
      <outputComplex>false</outputComplex>
      <pixelSpacingInDegree>0</pixelSpacingInDegree>
      <pixelSpacingInMeter>20.0</pixelSpacingInMeter>
      <saveBetaNought>false</saveBetaNought>
      <saveDEM>false</saveDEM>
      <saveGammaNought>false</saveGammaNought>
      <saveIncidenceAngleFromEllipsoid>false</saveIncidenceAngleFromEllipsoid>
      <saveLatLon>false</saveLatLon>
      <saveLocalIncidenceAngle>false</saveLocalIncidenceAngle>
      <saveProjectedLocalIncidenceAngle>false</saveProjectedLocalIncidenceAngle>
      <saveSelectedSourceBand>true</saveSelectedSourceBand>
      <saveSigmaNought>false</saveSigmaNought>
      <sourceBandNames/>
      <standardGridOriginX>0</standardGridOriginX>
      <standardGridOriginY>0</standardGridOriginY>
    </parameters>
  </node>
  <node id="write">
    <operator>Write</operator>
    <sources>
      <sourceProduct refid="terrain-correction"/>
    </sources>
    <parameters class="com.bc.ceres.binding.dom.XppDomElement">
      <clearCacheAfterRowWrite>false</clearCacheAfterRowWrite>
      <deleteOutputOnFailure>true</deleteOutputOnFailure>
      <file>result.tif</file>
      <formatName>GeoTIFF-BigTIFF</formatName>
      <writeEntireTileRows>false</writeEntireTileRows>
    </parameters>
  </node>
</graph>

Run the graph

In [ ]:

g.run()

In [ ]: