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STACK tutorial

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This service provides a multi-mission and multi-temporal image stack of co-located products coming from different optical and SAR sensors against a reference image. It performs resampling and warping of the secondary datasets and the stacking of each secondary with the reference.

đź“• STACK service description and specifications are available in this section.

Select the processing

  • After the opening of the activation workspace (e.g. [Act-738/Call-857] Flood Large/Earthquake/Tsunami in Indonesia, on the training instance of the processing Environment), in the right panel of the interface, open the "Processing Service" tab and select the processing service “Co-located stacking”.

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The "Co-located stacking (STACK)" panel is displayed in the right panel of the interface with a series of parameters values to be filled-in.

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Reference input

  • Select the area for which you want to do an analysis, e.g over Palu.

  • From the Navigation and Search toolbar (located in the upper left side of the map), click on “Spatial Filter” and draw a square around the city of Palu near the mouth of the river. This spatial filter allows you to select only the EO data acquired over this area.

  • From the top of the left panel, use Filter Criterias to search for “Optical” and "WorldView-1", "WorldView-2" and "WorldView-3" data collections from the list.

  • Once these filters are in place the list will be updated as the one shown in the next image.

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Fill the parameters

  • After the definition of spatial and time filters, you can apply the co-located stacking, by importing, for example, three pan assets from a set of three Panchromatic images from WV-1, WV-2 and WV-3 data. The first reference can be the WorldView-1 PAN image acquired on 02/10/2018, the second one can be the WorldView-2 PAN image acquired on 01/10/2018, and the third one the WorldView-3 PAN image acquired on 02/10/2018.

  • Now you can fill the parameters as following:

  • Insert as job name “STACK WV-1-2-3 PANs 2018 Palu, Indonesia”.
  • Drag and Drop the WorldView-1 calibrated dataset layer in the "Input product reference(s)” field.
  • Drag and Drop also the WorldView-2 calibrated dataset layer in the "Input product reference(s)” field.
  • Drag and Drop also the WorldView-3 calibrated dataset layer in the "Input product reference(s)” field.
  • Insert pan for the WV-1 dataset as list of comma separated bands in the "List(s) of comma separated band(s)” field.
  • Insert pan for the WV-2 dataset as list of comma separated bands in the "List(s) of comma separated band(s)” field.
  • Insert pan for the WV-3 dataset as list of comma separated bands in the "List(s) of comma separated band(s)” field.
  • If needed, to define an “Area of interest as Well Known Text”, apply as AOI the drawn polygon defined with the area filter. Click on the button in the left side of the AOI ad WKT parameter box and select the option AOI from the list to automatically define the WKT values.
  • The remaining optional parameter to be filled in is the one dedicated to the insertion of s-expressions that can be used to create additional bands generated from the ones present in the stack. As an example, the following s-expression can be inserted to generate a forth band in the stack as average of the three input panchromatics: “average:(mean 1.pan 2.pan 3.pan)”.

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Run the job

  • Click on the button Run Job and see the Running Job

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Results: download and visualization

  • Once the job is completed, click on the button Show results

  • See the result on the map. The preview appears within the area defined in the spatial filter.

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  • To get more information about the product just click on the preview in the map, a bubble showing the name of the layer collocated-stack” will appear and then click on the Show details button. In the left panel of the interface, all the details of the layer of the product will appear. It is also possible to customize the overview on the fly by clicking on Layer Styling and Combine Assets.

  • Finally, you can also save the parameters employed in this job by clicking on the “Export params” button in the left panel. This allows you to copy all your entries to the clipboard. This is meant to be used for a quick re-submission of a similar job after a fine tuning of the parameters. Below is reported the syntax which includes all the parameters employed in this example.

{
   "input_reference": [
      "https://catalog.charter.uat.esaportal.eu//charter/cat/[chartercalibrateddataset,{callid857},mission_worldview_1]/search?format=json&uid=call857_WV01S00_854583E119_9147222018100200000000PN00-calibrated",
      "https://catalog.charter.uat.esaportal.eu//charter/cat/[chartercalibrateddataset,{callid857},mission_worldview_2]/search?format=json&uid=call857_WV02S00_917500E119_8956942018100100000000PN00-calibrated",
      "https://catalog.charter.uat.esaportal.eu//charter/cat/[chartercalibrateddataset,{callid857},mission_worldview_3]/search?format=json&uid=call857_WV03S00_875416E119_8884722018100200000000PN00-calibrated"
   ],
   "bands": [
      "pan",
      "pan",
      "pan"
   ],
   "aoi": "POLYGON((119.845 -0.905,119.845 -0.881,119.875 -0.881,119.875 -0.905,119.845 -0.905))"
}