Aquaveo & Water Resources Engineering News

Refining Quadtree Grids in SMS

Using the Surface-water Modeling System (SMS), you can model quadtree grids for use with numeric models such as CMS-Flow. Quadtrees are part of the UGrid module in SMS making them a type of unstructured grid. When creating quadtrees in SMS, you can choose to have uniform cell sizes, or you may choose to refine the cells in some areas. When refining a quadtree, there are a couple methods and some tips to keep in mind.

The first method for refinding grid cells in a quadtree is to simply select the cells you want to refine using the Select Elements tool, then right-click and use the Refine Cells(s) command. This will equally divide the cells into smaller, more refined, cells. This method is useful for small-scale refinement in localized areas. However, using this method can be tedious if there are multiple areas on the quadtree that need refinement.

Example of the Quadtree Refinement in GMS

The second method for refining quadtrees is preferred in most cases. This method involves setting refinement parameters in the Quadtree Generator coverage. If you are familiar with SMS’s Cartesian grid generator coverage and mesh generator coverage, you will find that it is similar to both of those coverages.

Like the Cartesian grid generator coverage, the quadtree coverage makes use of a grid frame to define the domain of the generated grid. In the grid frame, you decide the size of the cells in the generated quadtree. It is recommended that this cell size be the largest reasonable cell size for the quadtree grid.

Like the mesh generator coverage, the quadtree generator coverage also makes use of polygons. When you create a polygon on the quadtree generator coverage, you can double-click on the polygon to open the Polygon Attributes dialog. In this dialog you can set the grid cell size for all cells that will be within the polygon.

Using both the grid frame and the polygon attributes, you define how the grid cells are refined for your quadtree with more precision. Try out refining quadtree grid in SMS today!

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Converting Between 2D and 3D Unstructured Grids

Many projects in the Groundwater Modeling System (GMS) start with an unstructured grid (UGrid). GMS supports both 2D and 3D UGrids. The type of UGrid you will need to use will depend on which numeric model you are using for your project. For this reason you may need to change a 2D UGrid to a 3D UGrid or vice versa. This blog post is going to review some of the tools for converting between 2D and 3D UGrids.

Typically, models like MODFLOW-USG or MODFLOW 6 will require a 3D UGrid. If you only have 2D UGrid data, this may require taking a 2D UGrid and converting it to be a 3D UGrid. Likewise, you may need to convert a 3D UGrid to be a 2D UGrid. This is more often done to correct uses with the 3D UGrid, but also to be able to use the data from the 3D UGrid with other applications.

GMS provides two tools in the Toolbox for changing between 2D and 3D UGrids: the Extrude to 3D UGrid tool and the UGrid 2D from UGrid 3D tool. The Toolbox is accessible through the Toolbox macro and these two tools are located with the Unstructured Grids tools.

Example of the Unstructured Grid tools in GMS

The Extrude to 3D UGrid tool converts a 2D UGrid to a 3D UGrid. The tool will allow you to select a 2D UGrid for extrusion, and then it lets you specify the number of layers and layer thickness for each of the new layers. This will extrude the 2D Ugrid to be a 3D UGrid with the specified number of layers that are at a uniform thickness. If you need layers to be at different thicknesses, you will need to edit the 3D UGrid using other tools in GMS.

The UGrid 2D from UGrid 3D tool will collapse a 3D UGrid to be a 2D UGrid. The tool allows you to select a 3D UGrid then select if the 2D UGrid should be created from the top or bottom of the 3D UGrid layers.

The unstructured grid tools in GMS allow you to have more options with how you work with UGrids and grid data for your groundwater projects. Try out the unstructured grid tools in GMS today!

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Exploring the Drawing Tools in WMS

When presenting a model in the Watershed Modeling System (WMS), you may need to clearly label locations or structures in your watershed model. For example, you may need a graphic with the names of your watershed branches clearly labeled. The Drawing Tools WMS provides a way to clearly annotate your watershed model. This blog post will cover some of the options and uses for these Drawing Tools.

Example of a drawing objects in WMS

The Drawing Tools contain options to draw objects including lines, rectangles, ovals, and text. When using the object creation tools, WMS provides attributes for changing the drawn object. Using the Select Drawing Object tool, you can double-click on a drawn object to pull-up the attribute options for the object. This includes options to change the line width, color, fill, arrows, and fonts.

It's important to note that drawing objects are layered. The first object you create will be below the next object you create. If you need to change how the objects are layered, the Drawing Tools contain tools for moving the objects forward or backward. To do this, select the object, then use the Move to Back, Move to Front, Shuffle Up, or Shuffle Down options to move the object.

You have the option to set a depth for the objects when creating new drawing objects. This depth is based on the project projection. Using the Drawing Depths command in the Drawing Objects menu, you can set a depth for the object you create. This can help make certain the drawing objects are above the grid, feature objects, or other items in the project.

It is important to note that the drawing objects are attached to the project projections. This means that drawing objects will stay fixed to the location of the model coordinates, not the Graphic Window position. This allows you to pan or zoom around your model and the drawing objects will stay fixed to the model location.

The drawing tools will be included when saving an image of the Main Graphics Window. This allows saving an image with annotations for use in presentation materials. To do this, use the Save As command and select the JPEG Image option for the file output.

The Drawing Tools are one of the options provided by WMS to let you make clear presentations for your watershed models. Try out the Drawing Tools in WMS today!

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Working with Functional Surfaces for UGrids in SMS

The functional surface option in SMS allows viewing data above a geometry. It has been an option in the 2D Mesh module. The functional surface option has been added for unstructured grids (UGrids) in the UGrid module starting with SMS 13.2. This post will give some guidance and tips for using functional surfaces with UGrids.

Example of a functional surface on a UGrid

Functional surfaces use any dataset as the elevation value for the surface. One of their most common uses is as a representation of the surface of the water above a UGrid. For example, the ocean’s surface in a CGWAVE model. However, functional surfaces can use any scalar dataset to inform the elevations.

A UGrid functional surface gets created by the New Functional Surface UGrid right-click command in the Project Explorer. Once created, right-click on the newly created functional surface to edit the display options. The Functional Surface Options dialog allows you to fine tune the display of your UGrid functional surface. Furthermore, selecting Other Display Options brings up UGrid-style display options.

Once you've set up your functional surface, you may need to make adjustments. Here are some tips on adjusting your functional surface displays depending on your situation:

  • If your dataset has large numbers, your functional surface might be very tall. To temper that effect, you could set the functional surface Z Magnification between 0 and 1.
  • If your dataset has very small numbers, your functional surface might appear completely flat. To more clearly see the rise and fall of the data values, set the Z Magnification to a value greater than 1.
  • If your functional surface is intersecting the UGrid, and you don't want it to, adjust the Elevation Z Offset.
  • If you want to add contours to your functional surface, click Other Display Options and turn on Face contours. Then click Contours to open the Contour Options.
  • If you still want to be able to see the UGrid through the functional surface, adjust the transparency. If you're using contours for the functional surface, you'll need to adjust the transparency in the Contour Options dialog.
  • If you want the functional surface to reference a specific dataset for its elevation, specify a User defined dataset.

Try out functional surfaces with UGrids in SMS today!

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