AVAMAP - Snow Avalanche mapping from Sentinel-1 data [norce]¶

2.1 Select the Processing Service¶

• Sign-in on the GEP portal: https://geohazards-tep.eu/
• Access the Thematic App containing the AVAMAP service.
• Open the tab Processing services from the right of the map and select the processing service AVAMAP.

2.2 Visualize preprocessed masks¶

The detection algorithm is restricted by a set of masks, including: * Radar mask: indicating lack of data due to radar shadow and layover (one mask for each relative orbit of Sentinel-1) * Runout mask: indicating avalanche runout zones based on the local topography * Land mask: Indicate land (vs ocean)

The detection algorithm will only detect snow avalanches where these three masks are non-zero. The masks has been prepared on the GEP plarform, and can be visualized by selecting Masks on the top pane:

The masks are prepared in terms of tiles, which appear as bounding boxes on the map: Select a tile and click Show details, followed by Show results at the bottom left to visualize the masks:

Here, for instance, is the avalanche runout mask highlighted. White areas indicate where avalanches can potentially be found given the local topography:

2.3 User inputs¶

Apart from a Job title, the tool only requires three inputs from the user: * Start date: ISO8601-formatted time (UTC) * End date: ISO8601-formatted time (UTC) * Area of interest: Polygon as WKT-string

The Area of interest must be a polygon, and inputted either as a WKT, or can be imported from a polygon drawn on the map:

To run the job, simply click Run Job.

2.4 Visualize results¶

Open the finished job, and click Show results on the Results pane to show the results. The results consists:

• Detections: Formatted as GeoJSON files, each containing a single detection as a polygon
• RGB composites: Constructed by a repeat-pass image pair, highlighting where the co-polarised backscatter has increased (green) or decreased (purple).

Here, results are shown for Lavangsdalen in Northern Norway