Subsidence Overlay overview

From Tygron Support wiki
Jump to: navigation, search

The Subsidence Overlay calculates subsidence by calculating oxidation and compaction in an iterative process to simulate the progression over a configurable number of years.

Calculation model steps

To calculate subsidence, the parameters are initialized based on data available in the Project.

Next, a number of steps are repeated to simulate the yearly subsidence, and to update the intermediately changing parameters for the calculation accordingly. These steps are repeated n times, where n is the amount of years configured.


Overlay Results

The overlay offers the following result types:

Legend

The legend of the subsidence overlays is automatically calculated, based on the amount of years being calculated by the overlay. The colors will remain constant based on average subsidence per year. I.e. if the amount of years is doubled, the values in the legend, corresponding to specific colors, are doubled as well. Because the legend displays total amounts of subsidence rather than averages, the displayed range of amounts changes when the amount of calculation years changes.

The legend of the groundwater overlays is constant, and will display a color from blue through yellow to red to indicate how wet the soil is. The closer the groundwater is to the surface of the land, the bluer the overlay. In contrast to the subsidence legends, the range of values for groundwater do not change.

Output

The output of all result types of the overlay is in meters. The results can be exported as GeoTIFF.

Timeframes

The amount of timeframes generated for the subsidence overlay are determined by Years (Subsidence Overlay) divided by Years per timeframe (Subsidence Overlay)

Subsidence output

The output of the grid of each subsidence result type is the subsidence in meters. Depending on the exact result type used, the output is the amount of subsidence as the result of one specific calculation, or the sum of all the calculations of subsidence.

The hover panel will display the following information:

  • The amount of subsidence taking place over the configured amount of years.
  • The current surface water level, and to what level it will have changed after the subsidence has taken place.
  • The indexation policy currently configured for this water area.

Groundwater level output

The output of the grid of each groundwater result type is the final distance from the groundwater level to the surface of the land in meters.

The hover panel will display the following information:

  • The level to which the groundwater will have changed, after the subsidence has taken place.

Final water level

The overlay can also write the final surface water level to the water area.