Module eoreader.products.sar
SAR products.
SAR data
Implemented SAR satellites
Satellites | Class | Product Types | Use archive |
---|---|---|---|
Sentinel-1 | S1Product |
SLC & GRD | Yes |
COSMO-Skymed | CskProduct |
DGM & SCS, (others should also be OK) | No |
TerraSAR-X | TsxProduct |
MGD (SSC should be OK) | No |
RADARSAT-2 | Rs2Product |
SGF (SLC should be OK) | Yes |
Warning
Satellites products that cannot be used as archived have to be extracted before use.
SAR Bands
According to what contains the products, allowed SAR bands are:
VV
(SarBandNames.VV
)VH
(SarBandNames.VH
)HH
(SarBandNames.HH
)HV
(SarBandNames.HV
)
You also can load despeckled bands:
VV_DSPK
(SarBandNames.VV_DSPK
)VH_DSPK
(SarBandNames.VH_DSPK
)HH_DSPK
(SarBandNames.HH_DSPK
)HV_DSPK
(SarBandNames.HV_DSPK
)
DEM bands
These bands need a valid worldwide DEM path positioned thanks to the environment variable EOREADER_SAR_DEFAULT_RES
DEM
SLOPE
See here for more information.
SAR satellites can only load DemBandNames.DEM
and DemBandNames.SLOPE
bands as the sun position does not impact SAR data.
The SLOPE
band is computed with the gdaldem
tool.
These bands need a valid worldwide DEM path positioned thanks to the environment variable EOREADER_SAR_DEFAULT_RES
.
Default resolution
The default resolution of SAR products depends on their type. Complex data are always converted back to ground range to be used.
The product resolution is read in the metadata file if possible, so the following values are given as hints:
Sentinel-1
Sentinel-1 | Single Look Complex (SLC) | Ground Range Detected (GRD) Full Resolution (FR) |
Ground Range Detected (GRD) High Resolution (HR) |
Ground Range Detected (GRD) Medium Resolution (MR) |
---|---|---|---|---|
StripMap (SM) | 1.5x3.6 m to 3.1x4.1 m | 3.5m | 10.0m | 40.0m |
Interferometric Wide swath (IW) | 2.3x14.1 m | 10.0m | 40.0m | |
Extra-Wide swath (EW) | 5.9x19.9 m | 25.0m | 40.0m | |
Wave (WV) | 1.7x4.1 m and 2.7x4.1 m | 25.0m |
COSMO-Skymed
COSMO-Skymed | Single-look Complex Slant (SCS) | Detected Ground Multi-look (DGM) Geocoded Ellipsoid Corrected (GEC) Geocoded Terrain Corrected (GTC) |
---|---|---|
Spotlight Mode-2 (S2) |
1.1-0.9x0.91m | 1.0m |
StripMap Himage (HI) |
3.0-2.6x2.4-2.6m | 5.0m |
StripMap PingPong (PP) |
11-10x9.7m | 20.0m |
ScanSAR Wide Region (WR) |
13.5x23m | 30.0m |
ScanSAR Huge Region (HR) |
13.5x38.0m | 100.0m |
TerraSAR-X
TerraSAR-X | Single-look Slant Range (SSC) | Multi Look Ground Range (MGD) Geocoded Ellipsoid Corrected (GEC) Enhanced Ellipsoid Corrected (EEC) Spatially enhanced (high resolution, SE) |
Multi Look Ground Range (MGD) Geocoded Ellipsoid Corrected (GEC) Enhanced Ellipsoid Corrected (EEC) Radiometrically enhanced (high radiometry, RE) |
---|---|---|---|
StripMap (SM) Single-Pol |
0.9x2.0m | 1.5m or 1.25m | 4.0m or 3.25m |
StripMap (SM) Dual-Pol |
0.9x2.5m | 3.0m | 5.5m or 4.5m |
High Resolution Spotlight (HS) Single-Pol |
0.9x0.8m | 1.5m or 0.5m | 2.0m or 1.5m |
High Resolution Spotlight (HS) Dual-Pol |
0.9x1.5m | 1.5m or 1.0m | 3.0m or 2.0m |
Spotlight (SL) Single-Pol |
0.9x1.3m | 1.5m or 0.75m | 3.0m or 1.75m |
Spotlight (SL) Dual-Pol |
0.9x2.6m | 3.5m or 3.4m | 8.5m or 5.5m |
Staring Spotlight (ST) Single-Pol |
0.5x0.2m | 0.4m or 0.2m | 0.8m or 0.4m |
ScanSAR (SC) Four Beams |
0.9x13m | 8.25m | |
ScanSAR (SC) Six Beams |
1.4x?m | 15.0m |
RADARSAT-2
RADARSAT-2 | Single-look complex (SLC) | SAR georeferenced extra(SGX) | SAR georeferenced fine (SGF) | SAR systematic geocorrected (SSG) | SAR precision geocorrected (SPG) | ScanSAR narrow beam (SCN) | ScanSAR wide beam (SCW) | ScanSAR fine (SCF) | ScanSAR sampled (SCS) |
---|---|---|---|---|---|---|---|---|---|
Spotlight | 1.3x0.4m | 1.0 or 0.8x1/3m | 0.5m | 0.5m | 0.5m | ||||
Ultra-Fine | 1.3x2.1m | 1.0x1.0 or 0.8x0.8m | 1.56m | 1.56m | 1.56m | ||||
Wide Ultra-Fine | 1.3x2.1m | 1.0m | 1.56m | 1.56m | 1.56m | ||||
Multi-Look Fine | 2.7x2.9m | 3.13m | 6.25m | 6.25m | 6.25m | ||||
Wide Multi-Look Fine | 2.7x2.9m | 3.13m | 6.25m | 6.25m | 6.25m | ||||
Extra-Fine | Full Res: 2.7x2.9m Fine Res: 4.3x5.8m Full Res: 7.1x5.8m Wide Res: 10.6x5.8m |
1 look: 2.0m 4 looks: 3.13m 28 looks: 5.0m |
1 look: 3.13m 4 looks: 6.25m 28 looks: 8.0m |
3.13m | 3.13m | ||||
Fine | 4.7x5.1m | 3.13m | 6.25m | 6.25m | 6.25m | ||||
Wide-Fine | 4.7x5.1m | 3.13m | 6.25m | 6.25m | 6.25m | ||||
Standard | 8.0 or 11.8x5.1m | 8.0m | 12.5m | 12.5m | 12.5m | ||||
Wide | 11.8x5.1m | 10.0m | 12.5m | 12.5m | 12.5m | ||||
Extended High | 11.8x5.1m | 8.0m | 12.5m | 12.5m | 12.5m | ||||
Extended Low | 8.0x5.1m | 10.0m | 12.5m | 12.5m | 12.5m | ||||
Fine Quad-Pol | 4.7x5.1m | 3.13m | 3.13m | 3.13m | 3.13m | ||||
Wide Quad-Pol | 4.7x5.1m | 3.13m | 3.13m | 3.13m | 3.13m | ||||
Standard Quad-Pol | 8.0 or 11.8x5.1m | 8.0x3.13m | 8.0x3.13m | 8.0x3.13m | 8.0x3.13m | ||||
Wide Standard Quad-Pol | 8.0 or 11.8x5.1m | 8.0x3.13m | 8.0x3.13m | 8.0x3.13m | 8.0x3.13m | ||||
ScanSAR Narrow | 25.0m | 25.0m | 25.0m | ||||||
ScanSAR Wide | 50.0m | 50.0m | 50.0m | ||||||
Ship (Detection of vessels) | 40.0m | 20.0m | |||||||
Ocean Surveillance | 50.0m | 35.0x25.0m |
GPT graphs
You can change the SAR GPT graphs used by setting the following environment variables:
EOREADER_PP_GRAPH
: Environment variables for pre-processing graph path.EOREADER_DSPK_GRAPH
: Environment variables for despeckling graph path
Warning
For performance reasons, the Terrain Correction
step is done before the Despeckle
step. Indeed this step is very
time-consuming and better done one time on the raw image than two times on both the raw and the despeckled image. Even
if this is not the regular way of handling SAR data, this shouldn't really affect the quality of any extraction done
after that.
What to know if you are changing a graph
Those graphs should have a reader and a writer on this model:
<graph id="Graph">
<version>1.0</version>
<node id="Read">
<operator>Read</operator>
<sources/>
<parameters class="com.bc.ceres.binding.dom.XppDomElement">
<file>$file</file>
</parameters>
</node>
<node id="Write">
<operator>Write</operator>
<sources>
<sourceProduct refid="????"/>
</sources>
<parameters class="com.bc.ceres.binding.dom.XppDomElement">
<file>$out</file>
<formatName>BEAM-DIMAP</formatName>
</parameters>
</node>
</graph>
Warning
Pay attention to set $file
and $out
and leave the BEAM-DIMAP
file format. The first graph must orthorectify your
SAR data, but should not despeckle it. The second graph is precisely charged to do it.
The pre-processing graph should also have a <code>Terrain Correction</code> step with the following wildcards that are set automatically in the module:
- `$res_m`: Resolution in meters
- `$res_deg`: Resolution in degrees
- `$crs`: CRS
- The nodata value should **always** be set to 0.
The default Terrain Correction
step is:
<node id="Terrain-Correction">
<operator>Terrain-Correction</operator>
<sources>
<sourceProduct refid="LinearToFromdB"/>
</sources>
<parameters class="com.bc.ceres.binding.dom.XppDomElement">
<sourceBands/>
<demName>GETASSE30</demName>
<externalDEMFile/>
<externalDEMNoDataValue>0.0</externalDEMNoDataValue>
<externalDEMApplyEGM>true</externalDEMApplyEGM>
<demResamplingMethod>BILINEAR_INTERPOLATION</demResamplingMethod>
<imgResamplingMethod>BILINEAR_INTERPOLATION</imgResamplingMethod>
<pixelSpacingInMeter>$res_m</pixelSpacingInMeter>
<pixelSpacingInDegree>$res_deg</pixelSpacingInDegree>
<mapProjection>$crs</mapProjection>
<alignToStandardGrid>false</alignToStandardGrid>
<standardGridOriginX>0.0</standardGridOriginX>
<standardGridOriginY>0.0</standardGridOriginY>
<nodataValueAtSea>true</nodataValueAtSea>
<saveDEM>false</saveDEM>
<saveLatLon>false</saveLatLon>
<saveIncidenceAngleFromEllipsoid>false</saveIncidenceAngleFromEllipsoid>
<saveLocalIncidenceAngle>false</saveLocalIncidenceAngle>
<saveProjectedLocalIncidenceAngle>false</saveProjectedLocalIncidenceAngle>
<saveSelectedSourceBand>true</saveSelectedSourceBand>
<outputComplex>false</outputComplex>
<applyRadiometricNormalization>false</applyRadiometricNormalization>
<saveSigmaNought>false</saveSigmaNought>
<saveGammaNought>false</saveGammaNought>
<saveBetaNought>false</saveBetaNought>
<incidenceAngleForSigma0>Use projected local incidence angle from DEM</incidenceAngleForSigma0>
<incidenceAngleForGamma0>Use projected local incidence angle from DEM</incidenceAngleForGamma0>
<auxFile>Latest Auxiliary File</auxFile>
<externalAuxFile/>
</parameters>
</node>
Default SNAP resolution
You can override default SNAP resolution (in meters) when geocoding SAR bands by setting the following environment variable:
EOREADER_SAR_DEFAULT_RES
(0.0 by default, which means using the product's default resolution)
Documentary Sources
SAR data
Sentinel-1
Others
Expand source code
# -*- coding: utf-8 -*-
# Copyright 2021, SERTIT-ICube - France, https://sertit.unistra.fr/
# This file is part of eoreader project
# https://github.com/sertit/eoreader
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
SAR products.
.. include:: ../../../documentation/sar_detailed.md
"""
Sub-modules
eoreader.products.sar.csk_product
-
COSMO-SkyMed products. More info here.
eoreader.products.sar.rs2_product
-
RADARSAT-2 products. More info here.
eoreader.products.sar.s1_product
-
Sentinel-1 products
eoreader.products.sar.sar_product
-
Super class for SAR products
eoreader.products.sar.tsx_product
-
TerraSAR-X products. More info here.