Apply Geometric Terrain Correction (Image Analyst Tools)

Summary

Orthorectifies the input synthetic aperture radar (SAR) data using a range-Doppler backgeocoding algorithm.

The range-Doppler backgeocoding approach computes the radar range and azimuth indices for every digital elevation model (DEM) grid point using the orbit state vectors. If no DEM is provided, the tool uses the tie points included in the metadata to perform the range-Doppler terrain correction.

Usage

Run the Despeckle tool on the input SAR data before running this tool.
This tool corrects geometric distortions in SAR imagery, accurately geolocates the imagery, and performs quantitative analysis.
This tool does not support a geodatabase as an output location.
If no DEM is specified, the tool will create an approximated DEM, which is interpolated from metadata tie points. Use the tie-point approach for full ocean radar scenes only; specify a DEM whenever land features are included in the radar scene.

Label	Explanation	Data type
Input Radar Data	The input radar data.	Raster Dataset; Raster Layer
Output Radar Data	The corrected geometric terrain radar data.	Raster Dataset
Polarization Bands (Optional)	The polarization bands that will be corrected. The first band is selected by default. Select all polarization bands if the output will be with the SAR Analysis tools.	String
DEM Raster (Optional)	The input DEM. If no DEM is specified or in areas that are not covered by a specified DEM, an approximated DEM, interpolated from metadata tie points, will be created. Use the tie-point approach for full ocean radar scenes only; specify a DEM whenever land features are included in the radar scene.	Raster Dataset; Raster Layer; Mosaic Layer
Apply geoid correction (Optional)	Specifies whether the vertical reference system of the input DEM will be transformed to ellipsoidal height. Most elevation datasets are referenced to sea level orthometric height, so a correction is required in these cases to convert to ellipsoidal height. Checked—A geoid correction will be made to convert orthometric height to ellipsoidal height (based on EGM96 geoid). This is the default. Unchecked—No geoid correction will be made. Use this option only if the DEM is provided in ellipsoidal height.	Boolean

ApplyGeometricTerrainCorrection(in_radar_data, out_radar_data, {polarization_bands}, {in_dem_raster}, {geoid})

Name	Explanation	Data type
in_radar_data	The input radar data.	Raster Dataset; Raster Layer
out_radar_data	The corrected geometric terrain radar data.	Raster Dataset
polarization_bands [polarization_bands,...] (Optional)	The polarization bands that will be corrected. The first band is selected by default. Select all polarization bands if the output will be with the SAR Analysis tools.	String
in_dem_raster (Optional)	The input DEM. If no DEM is specified or in areas that are not covered by a specified DEM, an approximated DEM, interpolated from metadata tie points, will be created. Use the tie-point approach for full ocean radar scenes only; specify a DEM whenever land features are included in the radar scene.	Raster Dataset; Raster Layer; Mosaic Layer
geoid (Optional)	Specifies whether the vertical reference system of the input DEM will be transformed to ellipsoidal height. Most elevation datasets are referenced to sea level orthometric height, so a correction is required in these cases to convert to ellipsoidal height. `GEOID`—A geoid correction will be made to convert orthometric height to ellipsoidal height (based on EGM96 geoid). This is the default. `NONE`—No geoid correction will be made. Use this option only if the DEM is provided in ellipsoidal height.	Boolean

Code sample

ApplyGeometricTerrainCorrection example 1 (Python window)

This example orthorectifies the radar data using a DEM.

import arcpy
arcpy.env.workspace = r"C:\Data\SAR"
outRadar = arcpy.ia.ApplyGeometricTerrainCorrection(
     "IW_manifest_TNR_CalB0_Dspk_RTFG0.crf", "VH;VV", r"C:\Data\DEM\dem10m.tif",
     "GEOID")
outRadar.save("IW_manifest_TNR_CalB0_Dspk_RTFG0_GTC.crf")

ApplyGeometricTerrainCorrection example 2 (stand-alone script)

This example orthorectifies the radar data using a DEM.

# Import system modules
import arcpy
from arcpy.ia import *

# Set local variables
in_radar = r"C:\Data\SAR\IW_manifest_TNR_CalB0_Dspk_RTFG0.crf"
out_radar = r"C:\Data\SAR\IW_manifest_TNR_CalB0_Dspk_RTFG0_GTC.crf"
polarization = "VH"
in_dem_raster = r"C:\Data\DEM\dem10m.tif"
geoid_correction = "NONE"

# Run
outRadar = arcpy.ia.ApplyGeometricTerrainCorrection(in_radar, polarization,
     in_dem_raster, geoid_correction)
outRadar.save(out_radar)

Environments

Cell Alignment, Compression, Current Workspace, NoData, Parallel Processing Factor, Pyramid, Raster Statistics, Resampling Method, Scratch Workspace, Snap Raster, Tile Size

Licensing information