SMS

Quick Polygon Generation from Raster Data

By aquaveo on June 25, 2024

Do you have raster data that you like to use to quickly generate polygons for your Surface-water Modeling System (SMS) project? SMS 13.3 introduces the Polygons from Raster Bounds, Polygons from Index Raster, and Polygons from Raster Nodata tools Each of these tools make use of raster data to generate polygons in the Map module. This can help you quickly define model domains or areas of interest in your model.

All of these tools can be found under the Coverages section in the Toolbox. Two of these tools can help resolve issues where the raster data is missing data. These "no data" areas can occur when the raster is trimmed, or when some of the data is incomplete in the database of origin.This can create holes in the data that will interfere with a model.

Using the Polygon from Raster Bounds tool creates a polygon that includes only the active region within the raster. It is especially useful when a downloaded raster has been trimmed to the model area. It eliminates the "no data" areas on the edges that were created by the trimming. This cleans up the data for the model. It can also be used when running models, such as for flooding, when one area needs a different coverage than the original.

With Polygons from Raster Nodata tool, areas that are "no data" inside active regions can be separated from the active regions so the "no data" areas don’t interfere with the model. For example, modeling a river, but not the flood plain, means you may want to exclude the land including islands in the river. Using this tool, polygons can be placed around all active areas and defined for the surface water model while the NODATA areas can then be ignored.

The Polygons from Index Raster tool can come in very handy when elevations and materials match fairly well. It will only work if an index raster is being used. Using this tool, polygons can be created around elevation changes in such a way that it becomes much easier to assign materials to polygons.

Creating the polygons can be a time consuming task. These tools can automate part of the process and eliminate some of the problematic areas within your surface modeling area for you. You can use more than one of these tools, as your model requires.

Head over to SMS and try out these tools in the Toolbox today.

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Accessing 3DEP Data for SMS

By aquaveo on June 11, 2024

The Surface-water Modeling System (SMS)[2] continues to expand the types of data it can use for your water modeling projects. For models in the United States, there is a very comprehensive set of elevation data that you can use in your modeling–3DEP data.

3DEP data is an amalgamation of high-resolution 3D elevation and 3D hydrography data from multiple sources. It is also "bare earth," meaning the images are ground-level only. No buildings, trees, shrubs, or ground cover of any sort have been included. Seeing the most precise shape of the ground can be very important to surface modeling. The high quality lidar data in the 3DEP project covers the vast majority of the United States and several of its territories. Coverage is becoming more comprehensive over time. We have added 3DEP as one of our options when you import map elevation information from the web.

When creating a surface-water model, you are looking for the USGS 3DEP Bare Earth DEM (North America) option from the web.

To access 3DEP data in SMS, do the following:

Click File | Import from Web… to open the Virtual Earth Map Location.
Make your location selection here (United States and some territories only)
You may have to set your Display Projection settings
When you reach the Data Service Options dialog box, scroll right until you see an option for USGS 3DEP Bare Earth DEM (North America).
You then save your image to the appropriate location on your computer, after you set or accept the default raster cell size.

Once you have saved your image, it will show up in the Project Explorer window under GIS Data. When saving, it will add the " _elevs.tif" extension to the name you chose. The elevation data can then be applied to your model in the usual way.

Head on over to SMS and see how 3DEP data can help your surface-water modeling.

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Making Use of Recent Files in SMS

By aquaveo on June 4, 2024

Jumping between multiple projects can be commonplace in most organizations. For this reason, the Surface-water Modeling System (SMS) includes a way to see your most recent projects. This feature makes it easier to jump between projects.

When starting SMS, you can see your recent projects by going to the File menu. Towards the bottom of the File menu, you will see the five most recent projects. Selecting any of these projects will load them into SMS.

Only the five most recent projects are listed in the File menu, but SMS provides a way to access more of your recent projects. Clicking the More… command under the recent files in the File menu will bring up the Recent Files dialog. The Recent Files dialog contains a list of recent projects. This list will go back to when the major version of the software was installed.

The Recent Files dialog allows you to search for past projects using the Search field at the top of the dialog. This can be immensely helpful when trying to find a project that has been neglected for a while.

Also helpful is a feature that lets you open the location of the project files. You can right-click on any project and select the Open Containing Folder command to bring up the folder containing the project files in the File Explorer window. This can help you locate files you haven’t been working with in a while and may have forgotten the location.

There are some caveats to this feature. If the project files have been moved, the project will still appear in the list of recent files but SMS will not be capable of importing the file because it is being directed to the wrong location. This is also true if a folder in the directory is renamed.

The Recent Files dialog provides a great tool to help you manage your projects in SMS. Head over to SMS and see what projects you have been working on recently!

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Taking Advantage of the SRH-2D Channel Calculator

By aquaveo on May 14, 2024

The Surface-water Modeling System (SMS) provides a useful tool that generates an estimated water surface elevation on an "Exit-H" boundary condition in an SRH-2D model. The Channel Calculator in SMS makes it easier to calculate water surface elevation values. It also gives you greater control of over the parameters

When building an SRH-2D model, the exit boundary will need to be defined. A constant elevation is often used, but this can not be sufficient in many cases. The Exit-H boundary condition is a stage type exit boundary where water surface elevation may be given as a constant number or as a stage-discharge or rating curve. The Channel Calculator is used to compute and assign a normal or critical water surface elevation for the outflow boundary condition. It also gives you greater control over the parameters used to determine the outflow conditions.

Example of the Channel Calculator in SMS

The Channel Calculator is accessed through the SRH2D Assign BC dialog. The Populate using Channel Calculator button appears at the bottom of the dialog when "Exit-H (subcritical outflow)" is selected as the BC Type and the Water Surface Elevation option has been determined.

The Channel Calculator specifies a composite roughness value, slope, and flow. SMS extracts a ground elevation cross section from a specified underlying elevation data source (mesh) that is used to compute the area and wetted perimeter. The calculator can make use of different types of elevation data sources which include DEMs, meshes, and scatter sets. Roughness and slope values will be required for the final calculation. Other options, such as the WSE offset, are optional and should only be used when necessary for your project.

The Channel Calculator will display a preview of the exit area cross section with normal and critical depth. When the Channel Calculator will save the values entered when exited. The values in the calculator can be changed later if needed.

The Channel Calculator in SMS gives you a useful tool for determining exit water-surface values for your SRH-2D projects. Try using it in SMS today!

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