Precondition:
The user has opened the app and has selected the hydrology layer.
Main success scenario:
The user successfully adds, edits, moves, removes and deletes dry, wet and watery areas in the hydrology layer.
For example: surface water runoff, natural reservoirs, gullies, rills, etc.
This includes positioning the areas in the appropriate location.
Default is moist.
Dry, wet and watery areas can be added by a small (rills) or big brush (surface water) to draw on the hydrology layer.
Alternative scenario:
The user accidentally edits, moves or removes an element and uses undo to correct the mistake.
The user accidentally adds an element and deletes it with the "delete" or "undo" functionality.
Error scenario:
The user attempts to add, move or edit a moisture or dry area but the app is experiencing technical difficulties and is unable to complete the request, displaying an error message.
Postcondition:
The user's map includes the added, edited, moved, removed or deleted moisture areas as desired.
Non-functional Constraints:
Performance: Map sizes with more than 1ha in 10000 raster elements (m²) per year should be usable without noticeable delays and acceptable memory overhead