Interferometry - Coherence CCD Time Line Workflow

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Interferometry - Coherence CCD Time Line Workflow

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Purpose

 

This functionality enables to execute, in a single iteration, the following processing sequence:

 

Import Generic SAR Data

Multitemporal Coherence (Time Line).

Coherence Geocoding

Color Composite Generation.

 

The final purpose of the CCD (Coherence Change Detection) Time Line processing chain is the generation of a geocoded coherence map. This tool allows to create geocoded coherence maps between several acquisitions (using the time line method: The first acquisition with the second, the second with the thirds, ...) in one single workflow.

The last step, Generate Color Composite, will create an RGB using the temporally first three coherence. In case of only 3 _slc as input, the red channel will be assigned to the first coherence, green and blue channel will both be assigned to the second coherence.

 

Technical Note

 

Details specific to each step implemented here are described in their respective reference help page. We recommend to read them carefully.

Note: this workflow allows importing and subsampling SAR data. In case SAR Data have already been imported and subsampled, these unnecessary steps will be skipped by setting to True these steps in the Input step - Parameters tab.

Only copolarized (VV or HH) data are allowed in this workflow.

 

Input

 

Input Files

 

Area of interest in Geographic Coordinates        

A vector file (.shp), or a Google Earth file (.kml or .kmz) can be upload to specify a region of interest.

This input reduces the disk space needs. This file is optional.

Note: Only AOI files in geographic coordinates (Lat/Long) are supported. If the needed shapefile is available only in another cartographic system, please use the Cartographic Transformation Shape tool to convert it in Lat/Long.

 

Input File List (Mandatory)

Input file name(s) of the Single Look Complex (_slc),  or original files. This file list is mandatory.

 

DEM/Cartographic System

 

Reference Type

The choice is given between the two following options:

 

Input DEM: the provided "Input Digital Elevation Model" file is used in the process previously imported;

 

 

DEM Download: The Digital Elevation Model Extraction tool is used to download an online digital elevation model. Various sources are available, see this section for further information.

 

Note: the choice of one source is compulsory.

 

Parameters

 

Grid Size

The grid size of the output data must be defined; the default unit of measure is meters.

Note that - for the Geographic projection - if values higher than 0.2 are entered they will be considered as metric units and then automatically, and roughly, converted from meters to degrees; if values lower than 0.2 are entered they will be considered as degree and used as such without any conversion.

 

Import Generic SAR Data

It allows importing and subsampling generic SAR data. Some parameters refer only to Sentinel-1 data , in this case "SENTINEL" is reported in the specific field to fill out. For more details refer to Import Data Generic SAR data.

 

Coherence

 

It brings to the principal parameters of the Coherence step. Refer to the relevant section technical note for further information about the process and other Preferences parameters.

 

Coherence geocoding

 

It brings to the principal parameters of the Geocoding step. Refer to the relevant section technical note for further information about the process and other Preferences parameters.

 

Generate Color Composite

 

It brings to the principal parameters of the Color Composite Generation step. Refer to the relevant section technical note for further information about the process and other Preferences parameters.

 

Output

 

Output file list

Output file name(s) of all geocoded file(s). This file list is mandatory.

 

Delete Temporary Files

By setting this flag, temporary files which are created in the intermediate steps, are automatically removed. All of the intermediate files are kept otherwise, refer to the Output lists relevant to each processing step for further information.

 

_cc_geo

Geocoded coherence image and associated header files (.sml, .hdr).

 

.tiff

RGB tiff file created using the temporally first three coherences. In case of only 3 _slc as input, the red channel will be assigned to the first coherence, green and blue channel will both be assigned to the second coherence

 

Details specific to the Units of Measure and Nomenclature of the output products can be found in the Data Format section.

 

General Function(s)

 

Preview

By setting this flag, the temporary files are made available to visualize after a single step in the chain.

 

Delete Temporary Files

By setting this flag to false, It is possible to keep all the temporary files created during the processing. The files are located in the ENVI Output Directory in a folder with the following name: SARsTmpDir_ddmmmyyyy_hhmmss

 

Save

Clicking this button allows to save and close the workflow at the actual step. After saving the workflow the window will be closed

 

Open

Clicking this button allows to open a previously saved workflow.

 

< Back

Clicking this button the previous step of the workflow is shown.

 

Next >

Clicking this button the actual step of the workflow is performed. once finished, the next step is shown.

 

Next >>>

Clicking this button all the steps are performed in succession and it is no more necessary to use the "Next >" button. Make sure that all settings in all the steps are correctly set before starting with this processing.

 

Close        

The window will be closed.

 

References

Consult the reference guide specific to each processing step.