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ESA > Join & Share > HASARD > HASARD Service in G-POD - User Manual and Terms and Conditions
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HASARD Service in G-POD - User Manual and Terms and Conditions

Terms and conditions

By using the HASARD flood mapping software integrated within ESA’s Research and Service Support processing platform, you agreed to accept all terms and conditions written in here.

User manual


The Luxembourg Institute of Science and Technology (LIST), in collaboration with the ESA Research and Service Support Team (ESA RSS), is sharing its Sentinel-1 based Synthetic Aperture Radar processing results for automatic flood delineation. The flood maps are obtained by applying an automatic unsupervised Change Detection algorithm to pairs of Sentinel-1 SAR images. Permanent water bodies are removed from the flood map.

Sentinel-1 SAR GRD images are downloaded from the ESA scihub (https://scihub.copernicus.eu/) and processed on GPOD resources using the ESA SNAP Toolbox (radiometric-calibration and geocoding).

HASARD STEP BY STEP PROCEDURE

1. Service selection from the GPOD list.
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2. Select basemap layer click on the plus icon on the top-right of the map.

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3. Select the area of interest and the time range

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4. Browse the list of available images

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5. Select two images from the same track:

  • flood image acquired during the flood event.
  • non-flood image acquired before/after the flood: double click on it when selecting.

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6. Parameters related to the flood detection algorithm
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The default parameters of the retrieval algorithm are indicated and do not need to be changed (see table below for a list of parameters related to the flood mapping algorithm).

ParameterDefaultRange
Filter size X / Y (Lee filter)33-9
Output product resolution in meter204-1000
HSBA minimum number of levels30-8
Bimodal Distribution verification (Ashman coefficient)2.42.1-2.7
Minimum number of pixels for the image tiles to process10001000-4000
Size (in pixels) of small objects to eliminate3010-100

However, when the selected images cover part of a sea, it is strongly recommended to tick the box 'Apply SeaMask', as this will speed up the processing and, in some cases, reduce the risk of over-detection.


7. Main parameters related to GPOD processing resources.

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8. Run the task: click the "Process it" button at the bottom of the page.


You can check the status of each task by consulting the Workspace section.

hasard output products

Output products of the service are the following:

1. A4 landscape flood map in PDF format,

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2. Flood vector in KML format for a rapid visualization in Google Earth,

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3. Compressed vector package (ZIP file) containing resulting vector files re-projected in the local UTM zone in SHP format about flood analysis and coverage of both reference and flood images,

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4. Compressed vector package (ZIP file) containing resulting vector files (EPSG: 4326) in SHP format about flood analysis and coverage of both reference and flood images,

5. Processed SAR reference image raster in GeoTIFF format,

6. Processed SAR flood image raster in GeoTIFF format,

7. Flood binary raster resulting from HSBA algorithm in GeoTIFF format,

8. Flood statistics in TXT format (also included into map).



 


Contributors to this page:
rpelich

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Page last modified on Monday 17 of June 2019 11:22:21 CEST by .