Using the Mask Subset Smoothing Option

The Surface-water Modeling System now includes two new tools in the toolbox to help you when your project requires any amount of dataset smoothing. Previous versions of SMS had you use the Dataset Toolbox to smooth a dataset. These new tools can do everything that the Dataset Toolbox used to do, and more.

Both the Smooth Datasets and Smooth Datasets by Neighbor tools are used to eliminate extreme slopes in a dataset, but they require different inputs, which will tell SMS how to incorporate the relationship between nodes. The Smooth Datasets tool uses an anchor and either an elemental area change or maximum slope for its calculations. Smooth Datasets by Neighbor uses the relationship between neighboring nodes and a selected interpolation method: average or inverse distance weighted. Note that the current version of these tools are designed to be used on node-based datasets, so they will only work on a mesh.

Both of the dataset smoothing tools have the option to include a subset mask. A subset mask dataset is great if there are nodes or elements in your mesh that you don't want included in the smoothing process. Here's some things you need to know when using a subset mask in your project.

Before you begin making changes, your subset mask dataset needs to have the same number of values in the same locations as the dataset being smoothed. A simple way to do this is to right-click on the original dataset in the Project Explorer and select Duplicate. Then you can make changes to the duplicate to create your subset mask dataset.

All the nodes you want to have included in the smoothing process need to be set to an S value of "1.0", and the nodes that should be excluded need an S value of "0.0". You can do this in any way you'd like, as long as all nodes get assigned one value or the other. There is a quick method that you may consider using to assign these values. With the Select Mesh Node tool active, right-click in the Graphics Window and choose Select All. With all nodes selected, enter either "1.0" or "0.0" in the S value field depending on whether the majority of nodes should be included or excluded. Then manually select the nodes that should be excluded from the smoothing process by either clicking and dragging a box around the nodes, or by holding down the Shift key and selecting nodes, so that you can select multiple nodes at the same time.

Now this dataset is ready to be used as a subset mask. Open the tool's dialog and select the dataset from the Subset mask dataset dropdown in the tool dialog and enter any other necessary inputs, then run the tool.

To see all the changes, go to the Data menu, select Map Elevation, and select the new smoothed dataset. This will apply the changes that the smoothing tool made to the mesh in the Graphics Window.

Head over to SMS and try including a subset mask dataset with the Smooth Dataset tool today!