Quadtree and Sub-Grid Sampling FAQ: Difference between revisions

For map outputs, the default for SGS models is to treat whether a 2D cell is wet or dry differently for water level surfaces compared to other map outputs. For water level surfaces a cell is wet if any part of the cell is wet (based on the lowest elevation from the SGS sampling), therefore, all partially wet cells are flagged as wet and will appear wet in the XMDF and other map output. The advantages here are as a modeller you can see which cells are wet even if they are only partially wet, and there is no need to buffer the water level surface for high quality mapping produced by subtracting the DEM from the water level surface. For all other map outputs a cell is deemed wet only if the water level in the cell exceeds the SGS elevation at the 2D cell centre. This was necessary as otherwise greatly distorted depth, hazard and other outputs could occur by taking the depth at the lowest part of the cell based on the SGS sampling. There are a range of commands that allow you to adjust the default settings for map outputs using SGS. For a more detailed discussion and a description of these new commands see Section 7.5 in the [[https://downloads.tuflow.com/TUFLOW/Releases/2020-0110/TUFLOW%20Release%20Notes.2020-10-AA.pdf 2020-10 Release Notes]].<br>