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<< Click to Display Table of Contents >> Interferometry - DInSAR Displacement Workflow |
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This functionality enables to execute, in a single iteration, the following processing sequence:
–Interferogram Generation and Flattening.
–Adaptive Filter and Coherence Generation.
–Phase to Displacement Conversion and Geocoding.
The final purpose of this processing chain is the generation of interferometric displacement maps.
Technical Note
Details specific to each step implemented here are described in their respective reference guide section. 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
Input Reference file
File name of the Reference data (_slc or manifest.safe in case of Sentinel-1 data that have not been already imported). This file is mandatory.
Input Secondary file
File name of the Secondary data (_slc or manifest.safe in case of Sentinel-1 data that have not been already imported). This file is mandatory.
Area of Interest
In case of SLC IW import, a vector file (.shp), or a Google Earth file (.kml or .kmz) can be upload to specify a region of interest. Only the bursts intersecting this region will be imported and cut during this step. This will reduce the import processing time and 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 geographic coordinates.
DEM/Cartographic System
Reference Type
The choice is given between the three following options:
•Input DEM: the provided "Input Digital Elevation Model" file is used in the process;
•Reference Height: in case that the Digital Elevation Model is not used, the parameters needed to define the Cartographic System, the pixel spacing and the reference height are compulsory;
•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 that the choice of one source is compulsory.
Parameters
•Skip Import SAR Data: it allows skipping the Import SAR Data step if set to True in case these data have already been imported;
•Skip Sample Selection : it allows skipping the Sample Selection SAR Geometry Data, if set to True, in case these data have already been sampled and the _cut files have already been created;
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 SAR Data
It allows importing 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.
Sample Selection SAR
It allows subsampling a spatial subset to be extracted from a single image or from an image stack. For more details refer to the sample selection in SAR geometry.
Interferogram Generation
It brings to the principal parameters of the Interferogram Generation step. Refer to the relevant section technical note for further information about the process and other Preferences parameters.
Adaptive Filter and Coherence
It brings to the principal parameters of the Adaptive Filter and Coherence Generation step. Refer to the relevant section technical note for further information about the process and other Preferences parameters.
Phase Unwrapping
It brings to the principal parameters of the Phase Unwrapping step. Refer to the relevant section technical note for further information about the process and other Preferences parameters.
Phase to Displacement Conversion and Geocoding
It brings to the principal parameters of the Phase to Displacement Conversion and Geocoding step. Refer to the relevant section technical note for further information about the process and other Preferences parameters.
Output
Output Root Name
Name of the output root. This file 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.
_dem
Input Digital Elevation Model resampled onto the specified cartographic system and grid size, with the associated header files (.sml, .hdr). Its areal extent is the same as the output SAR products.
_cc_geo
Geocoded coherence with the associated header files (.sml, .hdr).
_ADF
Maximum slope direction values, with the associated header files (.sml, .hdr).
_IDF
Maximum slope inclination values, with the associated header files (.sml, .hdr).
_SD
Displacement values along the maximum slope direction, with the associated header files (.sml, .hdr).
_UD
Displacement values in the direction specified as azimuth and inclination degrees (i.e. custom direction), with the associated header files (.sml, .hdr).
_VD
Vertical displacement values, with the associated header files (.sml, .hdr).
_disp
Slant Range (satellite view direction) displacement values, with the associated header files (.sml, .hdr).
_precision
Estimate of the data quality with the associated header files (.sml, .hdr). This file is generated only if the coherence file is entered as input.
_ALOS
Azimuth Line of Sight with the associated header files (.sml, .hdr). Positive angles are measured clockwise from the North; negative angles are measured counterclockwise from the North.
_ILOS
Incidence angle of the Line of Sight with the associated header files (.sml, .hdr). The angle is measured between the Line Of Sight and the vertical on the ellipsoid (flat earth).
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.