Available with Image Analyst license.
The Synthetic Aperture Radar (SAR) Feature Detection Wizard guides you through the entire ocean detection and extraction workflow from start to finish. Working with SAR data for feature detection requires multiple data processing steps, parameter selection, and feature extraction. The wizard provides a guided workflow that is composed of best practices and a simplified user experience to perform feature detection using Level-1 SAR data. The wizard currently supports ocean feature extraction and shoreline mapping.
The wizard consists of four steps:
- Select the feature types
- Specify the inputs
- Specify the detection settings
- Specify the outputs
Open the Feature Detection Wizard
To access the SAR Feature Detection Wizard, complete the following steps:
- In the Contents pane, select a SAR dataset.
- Click the SAR tab.
- In the Analysis group, click the SAR Tools drop-down menu, and choose Feature Detection Wizard.
The Feature Detection Wizard pane appears.
Select Feature Type
The first page of the Feature Detection Wizard is the Select Feature Type page. This page is used to select the type of feature to detect. The feature specified here determines the processing steps and the detection method in the subsequent pages.
Only one feature type can be selected for each configuration.
- Land And Water—Delineate shorelines by finding land and water bodies. This applies to both inland water bodies, such as lakes, rivers, and reservoirs, and ocean coastlines.
- Bright Ocean Objects—Detect bright ocean features with strong radar backscatters, such as ships, oil platforms, and offshore wind turbines.
- Dark Ocean Areas—Detect dark ocean features with low radar backscatter, such as oil spills and algae blooms.
Inputs
The second page of the wizard allows users to specify the input SAR dataset.
Authentication For Orbit Correction
If the input is a Sentinel-1 dataset, an additional section for Authentication For Orbit Correction appears. This section is not applicable for non-Sentinel-1 datasets.
- Username—The Copernicus Data Space Ecosystem login credential username.
- Password—The Copernicus Data Space Ecosystem login credential password.
- Cloud Storage Correction—The Copernicus Data Space Ecosystem cloud storage connection file.
Orbit correction is performed automatically based on availability. If precise orbit state vectors (OSVs) are available, they are downloaded and used. If precise OSVs are not available, restituted OSVs are downloaded. If neither is available, orbit correction is skipped.
Note:
Restituted OSVs are typically available within three hours of image acquisition, while precise OSVs may take up to three weeks. To learn more about how to set up your user account from the Copernicus Data Space Ecosystem, see details within the Download Orbit File tool.
Elevation
Elevation information is used to orthorectify the input SAR data.
- DEM—The input DEM. If the input radar data is not orthorectified, this DEM will be used to orthorectify the data.
- Apply Geoid Correction—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.
Area of Interest
The Area of Interest specifies the area that will be processed by the wizard. It can be from an input raster or feature class. By default, the entire input SAR dataset will be used.
Detection settings
The third page of the wizard allows users to configure detection parameters. These settings vary depending on the selected feature type.
Land and Water
The Minimum Area to Detect is the minimum area to extract as a water body. The default value is 50,000 square meters.
Bright Ocean Objects
| Parameter | Description |
|---|---|
Minimum Object Width | The minimum width of an object to be detected. The width must be a positive value. The default value is 10 meters. |
Maximum Object Width | The maximum width of an object to be detected. The width must be a positive value. The default value is 100 meters. |
Minimum Object Length | The minimum length of an object to be detected. The length must be a positive value. The default value is 50 meters. |
Maximum Object Length | The maximum length of an object to be detected. The length must be a positive value. The default value is 500 meters. |
Shoreline Exclusion Buffer | Specifies a buffer distance around the land-ocean mask. Features within this buffer zone are excluded from detection. The default value is 100 meters. |
Mask Out Land Using | Specifies the method used to mask out land.
If Land Polygons or Water Polygons is selected, the feature class must also be specified |
Mask Features | The feature class that delineates the Land Polygons or Water Polygons. |
Dark Ocean Areas
| Parameter | Description |
|---|---|
Minimum Area to Detect | The minimum area to be detected. The default value is 50,000 square meters. |
Shoreline Exclusion Buffer | Specifies a buffer distance around the land-ocean mask. Features within this buffer zone are excluded from detection. The default value is 100 meters. |
Mask Out Land Using | Specifies methods to mask out land. If Land Polygons or Water Polygons is selected, users need to provide the features:
|
Mask Features | The feature class that delineates the Land Polygons or Water Polygons. |
Outputs
The final page of the wizard displays a log view after clicking Run. Users can choose to save the processed SAR data.
| Parameter | Description |
|---|---|
Output Detection Results | The results of the Feature Detection Wizard. The default output file names are generated based on the input layer and selected feature type. |
Save Processed SAR Dataset | Specifies whether to save the processed SAR data as a raster dataset.
|
Output SAR Dataset | The file directory and name of the processed SAR dataset. |