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Purpose

 

This tool extracts the ellipsoidal elevation of an image.

Technical Note

 

This tool is specifically dedicated to geocode intensity SAR data characterized by the presence of sea water. The different elevation of the sea level may cause geocoding issues. The sea level, considered at elevation of 0 once the Geoid is used as reference, does not have the same elevation once the ellipsoid reference is considered.

The need of having ellipsoidal height to properly geocode satellite images, induced user to subtract the geoid component to have the reference ellipsoidal height. For this reason this tool allows to extract the reference ellipsoidal height in SAR images.

Even though this tool is created for ship detection on sea water, it can be applied to get the ellipsoidal reference height on lake water. The elevation value of the lake water has to be known and it can be set in Parameter/OtherParameters/Reference heights.

Input Files

 

OPTIONAL Reference Slant Range Image

Input file(s) name of the image to be used as geographic reference for the Digital Elevation Model extraction. This file is mandatory if the cartographic co-ordinates are not specified. In case a geocoded image is used, the "Cartographic System" specified below must be the same of the reference image. The geographical extent of the output Digital Elevation Model corresponds to the total coverage of the Reference file list.

 

DEM/Cartographic System

 

Output Projection

The parameters relevant to the Cartographic System of the output Digital Elevation Model must be entered:

 

State

Definition of the country or general projection systems.

 

Hemisphere

Definition of the hemisphere. This is chosen according to the selected State and Projection.

 

Projection

Definition of the projection system of the selected State. In case that a general projection system is selected in State, the Projection is automatically set.

 

Zone

Definition of the zone. This is chosen according to the selected State and Projection.

 

Ellipsoid

Definition of the ellipsoid. This is chosen according to the selected State and Projection.

 

Datum Shift Parameters

Definition of the datum shift parameters. These are chosen according to the selected State and Projection.

 

Reference Height

A reference ellipsoidal height can be provided. Default Reference Height is 0.

 

Parameters - Principal Parameters

 

Grid Size

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

 

Subtrct Geoid

The selected geoid component is subtracted to the input Digital Elevation Model.

 

Geoid Type

 

EGM96

Earth Gravitational Model 96.

 

EGM2008

Earth Gravitational Model 2008.

 

Parameters - Global

 

It brings to the general section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

 

Parameters - Other Parameters

 

It brings to the general section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

 

Output Files

 

Output DEM file

Output file name of the extracted and mosaiced Digital Elevation Model. This file is mandatory.

 

RefH_dem        

Extracted Digital Elevation Model, with user-defined projection and grid size, and associated header files (.sml, .hdr).

 

Details specific to the measurement units and nomenclature of the output products can be found in the Data Format section.

 

General Functions

 

Exec

The processing step is executed

 

Store Batch        

The processing step is stored in the batch list. The Batch Browser button allows to load the batch processing list.

 

Close        

The window will be closed.

 

Help

Specific help document section.

 

 

Specific Function(s)

 

None.

 

See Also

 

Task, SARscapeBatch object, SARscapeBatch script example

 

References

 

None.