Table 2 Overview of layers used
Map layers Description
Cadastral map Allows for analysis per cadastral plot to inform individual landowners on the current status of their properties.
Flow path at flood levels (‘Stroombanen’ in Dutch) Divides floodplains in flow paths and flowless areas. Hydraulic roughness in flow paths is prioritized by the river manager.
Classification vs. legal map Gives color-coded information on the deviations from the legal map – green colors represent classes with a lower hydraulic roughness, yellow – no difference, orange and red -undesired deviation from the legal map with increased vegetation roughness.
Classification Shows the classification of the selected satellite image (both for daily and annual images).
Legal vegetation map Shows the reference legal map (‘Legger’ in Dutch).
Satellite image Allows for visual inspection in RGB of the selected satellite image for detection of anomalies due to e.g. nebula or small clouds.
Aerial photograph Allows for detailed visual comparison with the most recent available aerial photograph (RGB 10*10 cm; automatically updated after every annual flight).

Classification and accuracies

The tool has been tested in the field (using mobile phones and tablet) by end-users and found to be a suitable help in the assessment of the status of the vegetation. Accuracy of the year classification is currently in the order of 80% while overall accuracy of single image classifications vary between 60 and 70%. A confusion matrix of the annual classification in the same year as the ground truth is shown in Table 3. The confusion occurs especially between classes in which vegetation is very much alike, such as the confusion between willow shrub and willow forest, and between rough natural grass lands and production grasslands.