TUFLOW HR Output: Difference between revisions
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Two additional methods have been added for the HR corner water level interpolation:
<font color="blue"><tt>HR Interpolation Approach </tt></font> <font color="red"><tt>== </tt></font> <font color="black"><tt>
* Method A
* Method B performs sheet flow checks at cell faces and ignores the water level from the upstream cell.
* Method C is the default option that applies the same sheet flow checks as the Method B. In addition, it also uses the number of wet SGS sampled points as a weighting that biases non-sheet flow cells that further improves the mapping to in-stream water levels.
The two images below present the high-resolution water level output at the same location, but with HR Interpolation Approach == Method B and Method C. As can be seen, the water level along the narrow stream is “smoother”.
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Any further questions please email TUFLOW support: [mailto:support@tuflow.com?Subject=TUFLOW%201D%20gates%20help support@tuflow.com]
<font color="blue"><tt>HR Thin Z Line Output Adjustment </tt></font> <font color="red"><tt>== </tt></font> <font color="black"><tt>
* “OFF”:
* “ON CELL SIDES” (default): two water levels, rather than one, are stored at cell corners selected by thin breaklines. These water levels are used to interpolate HR water levels on either side of thin breaklines. This option produces a sudden drop in water level across the breakline as illustrated in the figure below, noting the sudden drop follows the 2D cell faces where the breakline is applied.
* “ON ALIGNMENT”: As an extension to the “ON CELL SIDES” option, this method moves and aligns the 2D cell corner vertices to the original alignment of the breakline for producing HR water level and depth. The arrows in the figure below show how vertices of the TIN are moved to align with the breakline. This can produce substantially improved high-resolution mapping along thin breaklines with substantial drops in water levels, especially for larger 2D cell sizes. Note that the cell corners are NOT shifted for the hydraulic calculations.
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Note the this feature (at present) only works for thin breaklines in Z Shape (2d_zsh) layers. Thick/wide breaklines raises more than 1 rows of cell centres and 2 rows of cell faces, and thus do not experience similar HR interpolation issue.
=Showing Face Elevations in _DEM_Z_HR Check File =
When modelling breaklines in TUFLOW, thin breaklines modify the cell face elevations but do not modify the cell storages. When outputting the high-resolution outputs, the user can choose whether the cell face elevations are included using the following .tcf command.
<font color="blue"><tt>HR Grid Output Use Face Elevations </tt></font> <font color="red"><tt>== </tt></font> <font color="black"><tt>{ON} | OFF</tt></font>
* “ON” (default): use face elevations in [[Check_Files_2d_DEM_Z_HR | _DEM_Z_HR]] check file. This option accurately shows the cell faces where water can be hydraulically blocked. However, when cell faces are angled with the thin breakline, this can create 'pockets' of lower elevations in the check file that does not exist in reality.
* “OFF”: Face elevations are not used in [[Check_Files_2d_DEM_Z_HR | _DEM_Z_HR]] check file. This is an useful option for report writing, as 'clean' high resolution DEM images can be generated reflecting all geometry updates except for the Thin Breakline updates at cell faces.
[[File:HR_Z_Use_Face_Elevations_ON.PNG|480px]] [[File:HR_Z_Use_Face_Elevations_OFF.PNG|480px]]<br>
'''HR Grid Output Use Face Elevations == ON (left) and OFF (right)'''
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