Purpose

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

The final purpose of this processing chain is the generation of a Radargrammetric Digital Elevation Model.

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.

Input

Input Files

Input Reference file
File name of the Reference data. This file is mandatory.

Input Secondary file
File name of the Secondary data. 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.

Stereo Matching Process

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

GCP Selection

Refinement GCP file (Mandatory)

Either a previously created Ground Control Point file (.xml) is loaded (Load GCP File) or the interface to create a new Ground Control Point file is automatically loaded (Create GCP File, refer to the "Tools>Generate Ground Control Point" for details). This file is mandatory.

Shift Refinement and Re-flattening

It brings to the principal parameters of the Shift Refinement and Re-flattening step. Refer to the relevant section technical note for further information about the process and other Preferences parameters.

Shift to Height Conversion and Geocoding

It brings to the principal parameters of the Shift to Height Conversion and Geocoding step. The default Spatial Wavelet Size (m) is adopted.

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

Digital Elevation Model with the associated header files (.sml, .hdr).

_dem.shp

By setting this flag the DEM is generated in vector (.shp) format.

_dem.las

By setting this flag the DEM is generated in point cloud (.las) format.

_cc_geo

Geocoded coherence with the associated header files (.sml, .hdr).

_precision

Estimate of the data quality with the associated header files (.sml, .hdr). This file is used during the Digital Elevation Model mosaicing (Tools).

_resolution

Spatial resolution based on the local incidence angle with the associated header files (.sml, .hdr). This file is used during the Digital Elevation Model mosaicing (Tools).

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.

The window will be closed.

References

Consult the reference guide specific to each processing step.

Interferometry - Stereo Digital Elevation Model Workflow

Interferometry - Stereo Digital Elevation Model Workflow

Purpose