Geo Plugin and Water Model Limits: Difference between pages

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The water model is based on this [[Water_Module_Theory|theory]].


A Geo Plugin is a definition for a connection which should be established when a new [[Project]] is created. One or more Geo Plugins can be defined in a [[Project Template]]. When that Template is used to create a new Project, the connections defined in the Geo Plugins are established, and data within the new [[Project]]'s extent is imported. Depending on the Geo Plugin's configuration, various types of data can be added to the new [[Project]] automatically.
The way this is calculated also has impact on practical use-cases. Below are some basics rules that need to be adhered to get a proper result.


==Types==
== Surface Waterway Rules ==
A Geo Plugin can be used to import the following types of data:
Waterways are also calculated as 2D surface flow (not a 1D-line). This has several advantages, like interaction with the shoreline and easy loading of geo-data but is also requires a proper setup of the grid and base data to get flow through waterways.


{|class=wikitable
1 The smallest waterway width needs to be at least 6-8x the cell width. So for example a 3m wide waterway channel (shoreline exclusive) needs to have 3/6 (or even 3/8) = ~0,4m grid cells.  
! Geo Plugin type
* This is because water must be able to flow from cell to cell especially also when the watery runs in a 45 degree angle to the square grid cells.
! Feature type
* When this rule is not adhered the [[Surface_model_(Water_Overlay)|surface theory]] does not work and a buildup or to lees water can occur.
! Effect
! Configurations
|-
| AREA
| Vector
| Adds [[Area]]s.
| Geolink:
* Matching Attributes
* Mapped Attributes
|-
| BUILDING
| Vector
| Adds [[Building]]s, except roads.
| Function
Geolink:
* Function
* Matching Attributes
* Mapped Attributes
|-
| ROAD
| Vector
| Adds [[Building]]s, specifically roads.
| Function
Geolink:
* Function
* Matching Attributes
* Mapped Attributes
|-
| TERRAIN_HEIGHT
| Grid
| The [[elevation model]] is updated with data from all sources. Data from earlier sources take precedence over later sources.
| Source(s)
|-
| WATER_BOTTOM
| Grid
| The [[elevation model]] is updated with data from all sources, but only in location with a [[Water Terrain]]. Data from earlier sources take precedence over later sources.
| Source(s)
|}


==Configuration==
2 When working with small grid cells (e.g. 0,5m cell width) the underlying elevation model (DEM) also needs to have this resolution.
When a Geo Plugin is created, a number of additional configurations can be entered to define how the source data is to be interpreted. Note that the availability of different configuration options are related to the kind of data the Geo Plugin is configured to import.
* For example when you have a 3m wide waterway channel and 0,5m grid cell, but the elevation model uses 10m cell accuracy all grid cells have the same (or interpolated height) and in case the waterway channel the bathymetry is averaged out.
* When this rule is not adhered the bathymetry becomes to shallow and water cannot flow properly. It can also result in overflow around shorelines because small levees are ignored.


; Layer id
== Impulse & Depth Rules ==
: If the data source structures its data in multiple layers of features, which layer should be used.
The calculation model is based on typical use cases and is therefor limited to the min/max values variables may take. Allow even larger min/max values is possible but has a drastic impact on performance and memory usage.
; CRS
: If the data source does not define its CRS properly, or does not define a CRS at all, which CRS to use (instead).
; Name attribute
: Which [[Attribute]]'s value should be used to name the imported features.
; Id attribute
: An Attribute which can uniquely identify features in the data source. This is used to detect duplicates of data being retrieved when the data from the data source must be retrieved in multiple passes.


===Sources===
1 Water depth (distance between bathymetry and water datum) is limited to max 100m. The water depth (h) is an important variable in the [[Surface_model_(Water_Overlay)|surface theory]] and having larger values increases the UV vector out of its accuracy and making the simulation unstable.
{{main|Project Source}}
Each Geo Plugin must obtain its data from a source. Sources are defined as [[Project Source]]s in the {{software}}. For vector data, only one source can be added. For grid data, multiple sources can be added.


===Geo Link===
2 Water speed (m/s) is also limited to a maximum of 10m/s or 36kmph which is faster then a high speed river in mountainous terrain.
{{main|Geo Link}}
A Geo Link is a subdefinition for a Geo Plugin. It provides a further definition of which data to import, and how to remap the [[Attribute]]s.


{{article end
3 Water depth also has a minimal value of 0,5 millimeter, a water depth less then 0,5 millimeter is ignored for the surface flow but is still counted in the overall water balance.
|notes=
* When mapping [[Attribute]]s, and importing a feature which has an [[Attribute]] targeted by the mapping, the imported [[Item]] will have only the mapped [[Attribute]] with the original [[Attribute]]'s value, and not the original [[Attribute]]. Attributes which are not mapped are included with the [[Item]] as is.
* When a Geo Link uses multiple sources for grid data, only locations with NO_DATA values can be further enriched by following sources. Locations where the value is 0 will not be overwritten, as 0 can be a valid value.
|seealso=
* [[Project Source]]
* [[Geo Share]]
|howtos=
* [[How to create a Geo Plugin to import Areas from the Geo Share]]
|videos=
{{video|link=https://www.youtube.com/watch?v=IhnEk7mp5hE|description=Integrating data using the Geo Share and Geo Plugins.|language=dutch}}
}}


[[Category:Items]]
 
== Breaches and Weirs ==
Breaches and weirs are 1D objects that connect to the 2D grid
 
1 A breach that [[Breach_growth_formula_(Water_Overlay)|grows]] over time to 100m width also needs a breach area of at least 100m width. As the breach grows more 2D cells are used to flush the water from the 1D object onto the 2D grid. For proper flow the grid cells also need to be small enough, e.g. a breach of 20m width on a 100m grid cell cannot create stable breach growth. Typically at least 10 cells are needed for a breach thus 100m width needs at least 10m cell width.
* This may result in less flow through the weir or shock-waves as the breach increases in large steps.
 
2 Same as the breach a Weir or inlet can also flush the water on multiple cells, thus rule 1 must be adhered too. Furthermore a 100m wide Weir must also be in a waterway channel of at least 100m wide.
* Creating a Weir that is 100m wide on a 3m wide channel may cause water to flow over the shorelines or no flow at all due to DEM averaging (shoreline + bathymetry).

Revision as of 11:48, 27 May 2022

The water model is based on this theory.

The way this is calculated also has impact on practical use-cases. Below are some basics rules that need to be adhered to get a proper result.

Surface Waterway Rules

Waterways are also calculated as 2D surface flow (not a 1D-line). This has several advantages, like interaction with the shoreline and easy loading of geo-data but is also requires a proper setup of the grid and base data to get flow through waterways.

1 The smallest waterway width needs to be at least 6-8x the cell width. So for example a 3m wide waterway channel (shoreline exclusive) needs to have 3/6 (or even 3/8) = ~0,4m grid cells.

  • This is because water must be able to flow from cell to cell especially also when the watery runs in a 45 degree angle to the square grid cells.
  • When this rule is not adhered the surface theory does not work and a buildup or to lees water can occur.

2 When working with small grid cells (e.g. 0,5m cell width) the underlying elevation model (DEM) also needs to have this resolution.

  • For example when you have a 3m wide waterway channel and 0,5m grid cell, but the elevation model uses 10m cell accuracy all grid cells have the same (or interpolated height) and in case the waterway channel the bathymetry is averaged out.
  • When this rule is not adhered the bathymetry becomes to shallow and water cannot flow properly. It can also result in overflow around shorelines because small levees are ignored.

Impulse & Depth Rules

The calculation model is based on typical use cases and is therefor limited to the min/max values variables may take. Allow even larger min/max values is possible but has a drastic impact on performance and memory usage.

1 Water depth (distance between bathymetry and water datum) is limited to max 100m. The water depth (h) is an important variable in the surface theory and having larger values increases the UV vector out of its accuracy and making the simulation unstable.

2 Water speed (m/s) is also limited to a maximum of 10m/s or 36kmph which is faster then a high speed river in mountainous terrain.

3 Water depth also has a minimal value of 0,5 millimeter, a water depth less then 0,5 millimeter is ignored for the surface flow but is still counted in the overall water balance.


Breaches and Weirs

Breaches and weirs are 1D objects that connect to the 2D grid

1 A breach that grows over time to 100m width also needs a breach area of at least 100m width. As the breach grows more 2D cells are used to flush the water from the 1D object onto the 2D grid. For proper flow the grid cells also need to be small enough, e.g. a breach of 20m width on a 100m grid cell cannot create stable breach growth. Typically at least 10 cells are needed for a breach thus 100m width needs at least 10m cell width.

  • This may result in less flow through the weir or shock-waves as the breach increases in large steps.

2 Same as the breach a Weir or inlet can also flush the water on multiple cells, thus rule 1 must be adhered too. Furthermore a 100m wide Weir must also be in a waterway channel of at least 100m wide.

  • Creating a Weir that is 100m wide on a 3m wide channel may cause water to flow over the shorelines or no flow at all due to DEM averaging (shoreline + bathymetry).