Water Model Limits - Revision history

Rudolf@tygron.nl: /* 2 For the best results the elevation model (DEM) needs to be of the same resolution */

2024-10-28T14:05:59Z

2 For the best results the elevation model (DEM) needs to be of the same resolution

← Older revision		Revision as of 14:05, 28 October 2024
Line 18:		Line 18:
	* For example when you have a 3m wide waterway channel and 0,5m grid cell, but the imported elevation model uses 10m cell accuracy all grid cells have the same (or interpolated height). Small elevation changes (like a waterway bathymetry) are lost in the average cell value.		* For example when you have a 3m wide waterway channel and 0,5m grid cell, but the imported elevation model uses 10m cell accuracy all grid cells have the same (or interpolated height). Small elevation changes (like a waterway bathymetry) are lost in the average cell value.
	* 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.		* 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.
	* See the [[~~Advanced_options_~~(~~New_Project_Wizard~~)]] page on how to change the project DEM resolution when creating a new project and optionally uploading your own bathymetry DEM using the [[~~Geo_Data_tutorial~~]].		* See the [[Advanced options (New Project Wizard)]] page on how to change the project DEM resolution when creating a new project and optionally uploading your own bathymetry DEM using the [[Geo Data tutorial]].
	* Note: to improve waterway bathymetry the model automatically lowers cells inside a water polygon, by using the lowest value instead of average. This can improve results but can never compensate for a high resolution DEM. You can test this behavior via [[Min_max_elevation_(Water_Overlay)\|Min/Max elevation]] under advanced options and comparing the [[Digital_Surface_Model_Overlay\|original DEM Overlay]] with the water child result [[Surface_elevation_result_type_(Water_Overlay)\|Surface Elevation]]~~<br style="~~clear~~:both">~~		* Note: to improve waterway bathymetry the model automatically lowers cells inside a water polygon, by using the lowest value instead of average. This can improve results but can never compensate for a high resolution DEM. You can test this behavior via [[Min_max_elevation_(Water_Overlay)\|Min/Max elevation]] under advanced options and comparing the [[Digital_Surface_Model_Overlay\|original DEM Overlay]] with the water child result [[Surface_elevation_result_type_(Water_Overlay)\|Surface Elevation]]{{clear}}

	= Impulse & Depth =		= Impulse & Depth =

Frank@tygron.nl: /* Calculation time */

2024-02-27T15:47:03Z

Calculation time

← Older revision		Revision as of 15:47, 27 February 2024
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	* 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.		* 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).		* 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).

	~~= Calculation time=~~
	~~See [[Calculation time (Water Overlay)]]~~

Frank@tygron.nl: /* Calculation time */

2024-02-27T15:46:51Z

Calculation time

← Older revision		Revision as of 15:46, 27 February 2024
Line 43:		Line 43:

	= Calculation time=		= Calculation time=
	See [[Calculation time]]		See [[Calculation time (Water Overlay)]]

Frank@tygron.nl: /* Breaches & Hydraulic structures */

2024-02-27T15:46:25Z

Breaches & Hydraulic structures

← Older revision		Revision as of 15:46, 27 February 2024
Line 41:		Line 41:
	* 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.		* 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).		* 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).

			= Calculation time=
			See [[Calculation time]]

Maxim@tygron.com at 11:06, 25 June 2022

2022-06-25T11:06:57Z

← Older revision		Revision as of 11:06, 25 June 2022
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	* So for example a 4m wide waterway channel needs to have 4m/8m = ~0,5m grid cells.		* So for example a 4m wide waterway channel needs to have 4m/8m = ~0,5m grid cells.
	* When this rule is not adhered the [[Surface_model_(Water_Overlay)\|surface theory]] may lead to invalid water flow, causing no flow at all or a lower throughput (m3/s).		* When this rule is not adhered the [[Surface_model_(Water_Overlay)\|surface theory]] may lead to invalid water flow, causing no flow at all or a lower throughput (m3/s).
	* It may also result in a double shoreline effect when two opposing shoreline are too close to each other preventing proper reconstruction of the water level (see [[Surface_model_(Water_Overlay)\|surface theory]]). Resulting in a minuscule impulse that leads to water buildup over time in stationary models (dutch "scheeftrekker" effect).		* It may also result in a double shoreline effect when two opposing shoreline are too close to each other and thus preventing proper reconstruction of the water level (see [[Surface_model_(Water_Overlay)\|surface theory]]). Resulting in a minuscule impulse that leads to water buildup over time in stationary models (dutch "scheeftrekker" effect).
	* Note: to flow water between buildings in dense urban areas the same rules apply.		* Note: to flow water between buildings in dense urban areas the same rules apply.
	* See the [[Grid Overlay]] page on how to change the grid cell size. When you have reached the smallest grid value (0,25m) you can also activate [[Increased_resolution_(Water_Overlay)\|Increased DEM Resolution]] under advanced options, when activated only 4 cells are needed.<br style="clear:both">		* See the [[Grid Overlay]] page on how to change the grid cell size. When you have reached the smallest grid value (0,25m) you can also activate [[Increased_resolution_(Water_Overlay)\|Increased DEM Resolution]] under advanced options, when activated only 4 cells are needed.<br style="clear:both">

Maxim@tygron.com at 11:06, 25 June 2022

2022-06-25T11:06:19Z

← Older revision		Revision as of 11:06, 25 June 2022
Line 10:		Line 10:
	* So for example a 4m wide waterway channel needs to have 4m/8m = ~0,5m grid cells.		* So for example a 4m wide waterway channel needs to have 4m/8m = ~0,5m grid cells.
	* When this rule is not adhered the [[Surface_model_(Water_Overlay)\|surface theory]] may lead to invalid water flow, causing no flow at all or a lower throughput (m3/s).		* When this rule is not adhered the [[Surface_model_(Water_Overlay)\|surface theory]] may lead to invalid water flow, causing no flow at all or a lower throughput (m3/s).
	* It may also result in a double shoreline effect ~~where~~ the ~~bathymetry creates a small~~ (~~partly underwater) levee in the channel with two adjacent opposing shorelines. The~~ [[Surface_model_(Water_Overlay)\|surface theory]] ~~only supports one shoreline (partly flooded cell~~) ~~direction per cell, this increases the height on the other side resulting~~ in a minuscule impulse that leads to water buildup over time in stationary models (dutch "scheeftrekker" effect).		* It may also result in a double shoreline effect when two opposing shoreline are too close to each other preventing proper reconstruction of the water level (see [[Surface_model_(Water_Overlay)\|surface theory]]). Resulting in a minuscule impulse that leads to water buildup over time in stationary models (dutch "scheeftrekker" effect).
	* Note: to flow water between buildings in dense urban areas the same rules apply.		* Note: to flow water between buildings in dense urban areas the same rules apply.
	* See the [[Grid Overlay]] page on how to change the grid cell size. When you have reached the smallest grid value (0,25m) you can also activate [[Increased_resolution_(Water_Overlay)\|Increased DEM Resolution]] under advanced options, when activated only 4 cells are needed.<br style="clear:both">		* See the [[Grid Overlay]] page on how to change the grid cell size. When you have reached the smallest grid value (0,25m) you can also activate [[Increased_resolution_(Water_Overlay)\|Increased DEM Resolution]] under advanced options, when activated only 4 cells are needed.<br style="clear:both">

Maxim@tygron.com: /* 1 The smallest waterway channel needs to be at least 8 cells wide */

2022-05-28T10:02:29Z

1 The smallest waterway channel needs to be at least 8 cells wide

← Older revision		Revision as of 10:02, 28 May 2022
Line 9:		Line 9:
	* This is because water must be able to flow from cell to cell especially also when the watery runs in a diagonal angle to the square grid cells.		* This is because water must be able to flow from cell to cell especially also when the watery runs in a diagonal angle to the square grid cells.
	* So for example a 4m wide waterway channel needs to have 4m/8m = ~0,5m grid cells.		* So for example a 4m wide waterway channel needs to have 4m/8m = ~0,5m grid cells.
	* When this rule is not adhered the [[Surface_model_(Water_Overlay)\|surface theory]] ~~leads~~ to invalid water flow, causing no flow at all or a lower throughput (m3/s).		* When this rule is not adhered the [[Surface_model_(Water_Overlay)\|surface theory]] may lead to invalid water flow, causing no flow at all or a lower throughput (m3/s).
	* It may also result in a double shoreline effect where the bathymetry creates a small (partly underwater) levee in the channel with two adjacent opposing shorelines. The [[Surface_model_(Water_Overlay)\|surface theory]] only supports one shoreline (partly flooded cell) direction per cell, this increases the height on the other side resulting in a minuscule impulse that leads to water buildup over time in stationary models (dutch "scheeftrekker" effect).		* It may also result in a double shoreline effect where the bathymetry creates a small (partly underwater) levee in the channel with two adjacent opposing shorelines. The [[Surface_model_(Water_Overlay)\|surface theory]] only supports one shoreline (partly flooded cell) direction per cell, this increases the height on the other side resulting in a minuscule impulse that leads to water buildup over time in stationary models (dutch "scheeftrekker" effect).
	* Note: to flow water between buildings in dense urban areas the same rules apply.		* Note: to flow water between buildings in dense urban areas the same rules apply.

Maxim@tygron.com: /* 2 For the best results the elevation model (DEM) needs to be of the same resolution */

2022-05-28T10:00:54Z

2 For the best results the elevation model (DEM) needs to be of the same resolution

← Older revision		Revision as of 10:00, 28 May 2022
Line 19:		Line 19:
	* 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.		* 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.
	* See the [[Advanced_options_(New_Project_Wizard)]] page on how to change the project DEM resolution when creating a new project and optionally uploading your own bathymetry DEM using the [[Geo_Data_tutorial]].		* See the [[Advanced_options_(New_Project_Wizard)]] page on how to change the project DEM resolution when creating a new project and optionally uploading your own bathymetry DEM using the [[Geo_Data_tutorial]].
	* Note: to improve waterway bathymetry the model automatically lowers cells inside a water polygon, by using the lowest value instead of average. This can improve results but can never compensate for a high resolution DEM. You can test this behavior via [[Min_max_elevation_(Water_Overlay)\|Min/Max elevation]] under advanced options and comparing the original DEM Overlay with the water child result [[Surface_elevation_result_type_(Water_Overlay)\|Surface Elevation]]<br style="clear:both">		* Note: to improve waterway bathymetry the model automatically lowers cells inside a water polygon, by using the lowest value instead of average. This can improve results but can never compensate for a high resolution DEM. You can test this behavior via [[Min_max_elevation_(Water_Overlay)\|Min/Max elevation]] under advanced options and comparing the [[Digital_Surface_Model_Overlay\|original DEM Overlay]] with the water child result [[Surface_elevation_result_type_(Water_Overlay)\|Surface Elevation]]<br style="clear:both">

	= Impulse & Depth =		= Impulse & Depth =

Maxim@tygron.com: /* 2 For the best results the elevation model (DEM) needs to be of the same resolution */

2022-05-28T09:59:44Z

2 For the best results the elevation model (DEM) needs to be of the same resolution

← Older revision		Revision as of 09:59, 28 May 2022
Line 19:		Line 19:
	* 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.		* 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.
	* See the [[Advanced_options_(New_Project_Wizard)]] page on how to change the project DEM resolution when creating a new project and optionally uploading your own bathymetry DEM using the [[Geo_Data_tutorial]].		* See the [[Advanced_options_(New_Project_Wizard)]] page on how to change the project DEM resolution when creating a new project and optionally uploading your own bathymetry DEM using the [[Geo_Data_tutorial]].
	* Note: to improve waterway bathymetry the model automatically lowers cells inside a water polygon, by using the lowest value instead of average. This can improve results but can never compensate for a high resolution DEM. You can test this behavior via [[Min_max_elevation_(Water_Overlay)\|Min/Max elevation]] under advanced options.<br style="clear:both">		* Note: to improve waterway bathymetry the model automatically lowers cells inside a water polygon, by using the lowest value instead of average. This can improve results but can never compensate for a high resolution DEM. You can test this behavior via [[Min_max_elevation_(Water_Overlay)\|Min/Max elevation]] under advanced options and comparing the original DEM Overlay with the water child result [[Surface_elevation_result_type_(Water_Overlay)\|Surface Elevation]]<br style="clear:both">

	= Impulse & Depth =		= Impulse & Depth =

Maxim@tygron.com: /* 2 For the best results the elevation model (DEM) needs to be of the same resolution */

2022-05-28T09:57:41Z

2 For the best results the elevation model (DEM) needs to be of the same resolution

← Older revision		Revision as of 09:57, 28 May 2022
Line 14:		Line 14:
	* See the [[Grid Overlay]] page on how to change the grid cell size. When you have reached the smallest grid value (0,25m) you can also activate [[Increased_resolution_(Water_Overlay)\|Increased DEM Resolution]] under advanced options, when activated only 4 cells are needed.<br style="clear:both">		* See the [[Grid Overlay]] page on how to change the grid cell size. When you have reached the smallest grid value (0,25m) you can also activate [[Increased_resolution_(Water_Overlay)\|Increased DEM Resolution]] under advanced options, when activated only 4 cells are needed.<br style="clear:both">

	===2 For the best results the elevation model (DEM) needs to be of the same resolution ===		===2 For the best results the elevation model (DEM) needs to be of the same resolution===
	[[File:Raster_baddepth.png\|thumb\|Elevation cell to big for waterway bathymetry]]		[[File:Raster_baddepth.png\|thumb\|Elevation cell to big for waterway bathymetry]]
	* 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). Small elevation changes (like a waterway bathymetry) are lost in the average cell value.		* For example when you have a 3m wide waterway channel and 0,5m grid cell, but the imported elevation model uses 10m cell accuracy all grid cells have the same (or interpolated height). Small elevation changes (like a waterway bathymetry) are lost in the average cell value.
	* 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.		* 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.
	* See the [[Advanced_options_(New_Project_Wizard)]] page on how to change the project DEM resolution when creating a new project and optionally uploading your own bathymetry DEM using the [[Geo_Data_tutorial]].		* See the [[Advanced_options_(New_Project_Wizard)]] page on how to change the project DEM resolution when creating a new project and optionally uploading your own bathymetry DEM using the [[Geo_Data_tutorial]].
	* Note: to improve waterway bathymetry the model automatically lowers cells inside a water polygon, by using the lowest value instead of average. This ~~only works when you have~~ a ~~lower~~ resolution DEM ~~then the calculation grid and~~ can ~~be deactivated~~ via [[Min_max_elevation_(Water_Overlay)\|Min/Max elevation]] under advanced options.<br style="clear:both">		* Note: to improve waterway bathymetry the model automatically lowers cells inside a water polygon, by using the lowest value instead of average. This can improve results but can never compensate for a high resolution DEM. You can test this behavior via [[Min_max_elevation_(Water_Overlay)\|Min/Max elevation]] under advanced options.<br style="clear:both">

	= Impulse & Depth =		= Impulse & Depth =