SliceAssembly-TOPSAR-Split is missing data

Microwave Toolbox Problem Reports
1

Hi STEPpers, I am running SliceAssembly to join four consecutive S1 SLC images, but the assembled result is missing data in the south.

However, when I run the same graph and omit the north-most image, the south-most data is included.

I encounter this issue in SNAP 6.0.4 with up-to-date modules, both on an Ubuntu machine with 400 GB RAM (via gpt ) and a Windows machine with 32 GB RAM via GUI. I tried tweaking the gpt.vmoptions , setting e.g. -Xmx64G , but it seemed to have no effect at all on memory usage or outcome.

Do you have any clue why this could be happening?

Please see the images and graph XML here: https://github.com/senbox-org/s1tbx/issues/54

2

From @valgur

my guess is that the BurstIndex range needs to be adjusted to include the bursts/content from all of the images in the output.

      <firstBurstIndex>1</firstBurstIndex>
      <lastBurstIndex>28</lastBurstIndex>
3

Alright, @valgur, seems like the narrow BurstIndex range on TOPSAR-Split was the actual problem. When I set <lastBurstIndex>36</lastBurstIndex>instead, I get the full data.

How do I know, programmatically, what lastBurstIndex should be? I am running the same graph via gpt with varying numbers of inputs. Can I just set it to some large number, like

4

Please list the input products so we can check what is going on.

5

Here is the graph:

<graph id="Graph">
  <version>1.0</version>
  <node id="SliceAssembly">
    <operator>SliceAssembly</operator>
    <sources>
      <sourceProduct.4 refid="ProductSet-Reader"/>
    </sources>
    <parameters class="com.bc.ceres.binding.dom.XppDomElement">
      <selectedPolarisations>VV</selectedPolarisations>
    </parameters>
  </node>
  <node id="TOPSAR-Split">
    <operator>TOPSAR-Split</operator>
    <sources>
      <sourceProduct refid="SliceAssembly"/>
    </sources>
    <parameters class="com.bc.ceres.binding.dom.XppDomElement">
      <subswath>IW1</subswath>
      <selectedPolarisations/>
      <firstBurstIndex>1</firstBurstIndex>
      <lastBurstIndex>28</lastBurstIndex>
      <wktAoi/>
    </parameters>
  </node>
  <node id="Write">
    <operator>Write</operator>
    <sources>
      <sourceProduct refid="TOPSAR-Split"/>
    </sources>
    <parameters class="com.bc.ceres.binding.dom.XppDomElement">
      <file>assembled.dim</file>
      <formatName>BEAM-DIMAP</formatName>
    </parameters>
  </node>
  <node id="ProductSet-Reader">
    <operator>ProductSet-Reader</operator>
    <sources/>
    <parameters class="com.bc.ceres.binding.dom.XppDomElement">
      <fileList>S1B_IW_SLC__1SDV_20180703T053055_20180703T053122_011642_01568A_3C50.zip,S1B_IW_SLC__1SDV_20180703T053120_20180703T053147_011642_01568A_EFF9.zip,S1B_IW_SLC__1SDV_20180703T053145_20180703T053213_011642_01568A_1EE3.zip,S1B_IW_SLC__1SDV_20180703T053211_20180703T053238_011642_01568A_FCC4.zip</fileList>
    </parameters>
  </node>
  <applicationData id="Presentation">
    <Description/>
    <node id="SliceAssembly">
      <displayPosition x="165.0" y="61.0"/>
    </node>
    <node id="TOPSAR-Split">
      <displayPosition x="300.0" y="61.0"/>
    </node>
    <node id="Write">
      <displayPosition x="415.0" y="61.0"/>
    </node>
    <node id="ProductSet-Reader">
      <displayPosition x="15.0" y="61.0"/>
    </node>
  </applicationData>
</graph>

so the list is

S1B_IW_SLC__1SDV_20180703T053055_20180703T053122_011642_01568A_3C50.zip
S1B_IW_SLC__1SDV_20180703T053120_20180703T053147_011642_01568A_EFF9.zip
S1B_IW_SLC__1SDV_20180703T053145_20180703T053213_011642_01568A_1EE3.zip
S1B_IW_SLC__1SDV_20180703T053211_20180703T053238_011642_01568A_FCC4.zip
6

Just for the record - lastBurstIndex 9999 works.

1 Like