1. The Main Map
The homepage is an interactive map displaying all available watersheds. Here is how to use it:
- Navigation: Use your mouse to pan and zoom on the map.
- Search: The search panel in the top left allows you to quickly find a basin by name. Start typing and suggestions will appear.
- Data layers: On the right, you can show or hide groups of basins (usually by national park) by checking or unchecking the boxes.
- View details: Click on a basin on the map to display a tooltip. Click on the 'View details' button to access the analysis page for that basin.
- Comparison: The 'Comparison' button in the search panel takes you to the historical analysis tool.
2. The Basin Details Page
This page provides a detailed analysis of the Snow Water Equivalent (SWE) for a single basin.
- Date selection: Use the month selector to choose the period you want to analyze. Data is displayed for the end of the selected month.
- SWE Gauge: The center gauge displays the SWE value (in mm) for the selected month. The color and fill provide a quick visual indication. Just below, you can see the percentage relative to the historical normal for that month.
- Main chart: This chart compares the current hydrological year trajectory (in red) with the historical average (dotted blue) and all past years' trajectories (in light gray). The X-axis represents the hydrological year, running from September to August.
- Local comparison: You can add up to 3 other basins from the same sector on the main chart for a direct comparison. Expand the 'Compare with other basins' section and check those that interest you.
- Actions: You can export the basin's time series data to CSV or download the basin outline in GeoJSON format.
3. The Historical Comparison Page
This tool allows you to compare SWE data in several ways.
- Comparison modes:
Inter-basin: Compare time series from multiple basins (up to 5) over a given period. Ideal for seeing how different basins behave over the same timeframe.Inter-annual: For a single basin, compare trajectories from several hydrological years. Ideal for identifying exceptional years (dry or wet).
- Selection: Use filters and the list to select the basins or years you wish to analyze.
- Period: In 'Inter-basin' mode, you can define a specific date range using the slider.
- Analysis: Click 'Show comparison' to generate the chart and a summary table with key statistics (average, maximum).
- Export: Once the chart is generated, you can export the compared data in CSV format.