Meshing M03 Draft MB DEL

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Tutorial Description

Read the Tutorial Introduction before starting this tutorial. It outlines the required links to download SMS, which we will use for mesh generation.

This tutorial is designed to introduce the skills required for creating a mesh and generating model bathymetry from multiple datasets, and builds on the skills introduced in Meshing Module 1 and Meshing Module 2. Specifically, this tutorial includes:

  • Definition of breaklines for defining channel elevations.
  • Use of multiple elevation data types to create a model bathymetry.
  • Creation and modification of a complex mesh, including the use of the topographic pre-processor TOPAZ.
  • Meshing techniques required for different areas of a model domain.

The workflow uses SMS Community Edition to develop a model mesh and bathymetry.

Model Domain

The tutorial focuses on Cudgen Creek, a small coastal estuary on the eastern Australian coastline. The mesh extends approximately 20 km north-south and 12km east-west to a depth of 50m.

M03 CC ModelDomain ahd 002.png

Requirements And Downloads

Requirement Brief Description
Meshing Data Download the Meshing Module 3 Data Package MADDY TODO link data.
Assumed Knowledge It is recommended to complete the Meshing Module 1 and Meshing Module 2 prior to completing this tutorial. If you run into any problems or need help, please contact support@tuflow.com

Prepare The Working Environment

Unzip the required Model Data to your preferred working location, for example E:\TUFLOWFV\Meshing_M03.

  • The Complete_Mesh folder has the files for the completed tutorial.
  • The Working folder is where we will save our files and build our mesh.
M03 Mesh folder structure.png

Note: All file paths referred to will be relative to this base directory. For example, Complete_Mesh\Cudgen_Creek_001.2dm refers to E:\TUFLOWFV\Meshing_M03\Complete_Mesh\Cudgen_Creek_001.2dm .

Provided Project files

To save time and allow focus on meshing techniques multiple files have been provided. Copy the following files from the Model_Data folder into the specified folders:

Model Data\ Copy to Description
Bathy_DEM_30m_AHD_MGA56.tif Working\DEM Combined offshore bathymetry and intertidal digital elevation model at a grid size of 30m.The data is represented in Australian Height datum AHD and UTM Zone 56 of the Geocentric Datum of Australia (GDA94) within Map Grid of Australia (MGA).
DEM_Catchment_5m_AHD_MGA56.tif Working\DEM Digital elevation model of the Cudgen Creek catchment at 5m grid size. The data is represented in Australian Height datum AHD and UTM Zone 56 of the Geocentric Datum of Australia (GDA94) within Map Grid of Australia (MGA).
Lake_Coast_survey_AHD_MGA56.csv Working\DEM Point survey data of the upstream lake and coastal zone. The data is represented in Australian Height datum AHD and UTM Zone 56 of the Geocentric Datum of Australia (GDA94) within Map Grid of Australia (MGA).
Sample_creek_survey_AHD_MGA56.TXT Working\DEM A sample of point survey data. The data is represented in Australian Height datum AHD and UTM Zone 56 of the Geocentric Datum of Australia (GDA94) within Map Grid of Australia (MGA).
Bathy_DEM_30m_AHD_MGA56.tif Working\DEM Bathymetry of the lower estuary at a 5m grid size. The data is represented in Australian Height datum AHD and UTM Zone 56 of the Geocentric Datum of Australia (GDA94) within Map Grid of Australia (MGA).
Model Data\ Copy to Description
Base_Data.map Working\Map SMS map data file that will assist in the generation of mesh and DEM. The data is represented in UTM Zone 56 of the Geocentric Datum of Australia (GDA94) within Map Grid of Australia (MGA).

Setup The SMS Project

Save The Workspace

Before we start meshing we'll set up our working projection and save a new SMS project.

Launch SMS and use the below steps and video to save the workspace in the Working folder:

1. From the menu bar select File > Save As.
2. Navigate to Working folder.
3. Save the workspace as Cudgen_Creek_001.sms

Set The Workspace Projection

Set the projection GDA 1994 MGA Zone 56 from the menu bar Display > Display Projection....

Use the below steps and video to set the workspace projection:

  1. Go to Display > Display Projection....
  2. Select Global projection.
  3. The Horizontal Projection dialog will appear. In the Filter strings: type GDA 1994 MGA Zone 56. Select the projection and OK > OK.

Load And Display The Data

Use the below steps and video to open and set the display options for map files and aerial imagery:

1. Select File > Open.... Navigate to Working\Map\Base_Data.map and Open. Specify the display as below:
  • Within the Map Data panel turn on Breaklines to view the current display.
  • Select Display Options DisplayOptionToolSMS.png.
  • In the Display Options select the point/Node dropdown and set the the colour to red.
  • Check the Vertex attributes are on and update symbol attributes to a crosshair symbol +.
  • Select OK > OK.
2. Select File > Add Online Maps.... From the Get Online Maps dialog select World Imagery > OK. Specify the display as below:
  • From the project panel right click on World Imagery and select Transparency....
  • Update the transparency to 30%. Select OK.

Constructing The Bathymetry

Constructing bathymetry for modelling purposes requires very careful and judicious use of a range of potentially disparate data, and so there is a need to be careful and clean. This section describes the process of constructing bathymetry using a variety of data types and techniques. The goal of this exercise is to create a bathymetric surface that seamlessly integrates both high and low resolution data, tailored to the specific spatial needs of the model domain. The examples demonstrated in this tutorial can be effectively applied to address data gaps in areas with limited data availability, such as small coastal estuaries. Notwithstanding this, it is important to note that studies often include a targeted and detailed data collection component, such as side scan survey retrieval, resulting in a high resolution Digital Elevation Model (DEM) or Triangulated Irregular Network (TIN) production. In such cases not all the techniques presented below will be required.  

Outcomes of this section include:

  • Creating breaklines.
  • Converting multiple elevation data types into scatter data.
  • Merging scatter sets.
  • Creating a raster.

Creating Breaklines

The examples provided in this section demonstrate techniques to build breaklines. Doing so is a core skill required to build bathymetric data sets for TUFLOW FV models, so investing time in learning this skill is worthwhile. In general, the goal is to digitise/construct breaklines as feature arcs in a map coverage that can then be both exported as a scatter set for geotiff creation and used directly within TUFLOW FV as 2d_zln breaklines at run time. One reason to initially build these breaklines as feature arcs is to draw on the extensive suite of geometry and interpolation functions offered in map coverages compared to scatter sets. Although some will be built via the steps below, the final breaklines for this model extent have been provided in the Map_Data and will be later used to build the model bathymetry.

Begin by opening the survey data as a scatter dataset. In this example the scatter data will serve as a visual aid for understanding the spatial distribution of the elevation values, which is essential for creating breaklines in a map coverage (see below). Use the below steps and video to import the survey data as a scatter set:

  1. Select File > Open.... Navigate to Working\DEM\Sample_creek_survey_AHD_MGA56.TXT and Open.
  2. The File Import Wizard dialog will appear. Specify the following:
    • Check that the File import option is set to Delimited.
    • The Column delimiter Tab should be checked. Select Next >.
    • Select Finish.
    • Select OK for the warning: Specify the projection for imported data.
    • The data is in the same projection as the project window. Select OK.
  3. Within the Project panel right click on Sample_creek_survey_AHD_MGA56 > Zoom to Scatter.
  4. Select Display Options DisplayOptionToolSMS.png and specify the following Scatter options:
    • Under the Points check Use contour color scheme.
    • Check Scalar values.
    • Select the Scalar values font options and update to font size to 11.
  5. Use the Select Scatter Point tool to view the elevations at each point. This now provides a foundation for subsequent digitisation of spatially detailed breaklines as feature arcs in a map coverage


Although breaklines can be created in a scatter set directly, they are limited to being constructed by joining existing depth-attributed scatter points only. Feature arcs drawn in a map coverage do not have this limitation so offer more flexibility in terms of more generally delineating breaklines, for subsequent conversion to scatter breaklines. The follow describes this process.


Since breaklines are created from feature arcs that can be snapped and interpolated to survey data, the survey data above must also be re-imported as a feature type within SMS. Follow the steps and video below to open the survey data as feature type data, which will enable us to construct the breaklines effectively:

  1. In the project panel right click on Map Data > New Folder. Rename it Breaklines
  2. Again select File > Open.... Navigate to Working\DEM\Sample_creek_survey_AHD_MGA56.TXT and Open.
  3. The File Import Wizard dialog will appear. Specify the following:
    • Check that the File import option are set to Delimited.
    • The Column delimiter Tab should be checked. Select Next >.
    • From the SMS data type dropdown select Feature Data
    • Select Create... and from the New Coverage dialog rename Area Property coverage Breaklines_gen.
    • Select OK > OK.
    • Select No when the the warning Arcs have not been mapped. Would you like to connect the points as one continuous arc? appears.
    • The data is in the same projection as the project window. Select OK.
    • Select OK for the warning: Specify the projection for imported data. As the data is in the same projection as the project window. Select OK.
  4. Using the Select Objects tool select the point within Breakline_gen and review the assigned elevations within the Z field. This data matches the scatter data set and will be used to interpolate elevations along breaklines.


With the survey data imported as a scatter (for depth guidance) and a coverage (for feature arc construction), breaklines are now able to be prepared.

The first breakline example involves interpolating the elevations along a feature arc between two survey points. Use the below steps and video as a guide:

  1. Zoom into the data (refer to video)
  2. Using the Create Feature Arc tool digitise an arc from elevation -2.30 to -2.32. Note snap the arc to each point (refer to the video). If snapping is not enabled refer to the Snapping Features section at Using Snapping in SMS.
  3. Using the Select Feature Arc tool select the new arc. Right click and select Redistribute Vertices.... Set the following attributes in the Redistribute Vertices:
    • From the drop down select Specified spacing.
    • Set an average spacing of 5. Select OK.
  4. Whilst the arc is still selected right click and select Smooth Arc(s).... Set the following attribute in the Smooth Arcs Tool dialog:
    • Set the Number of neighbors to 7.
    • Select OK.
  5. Again right click on the arc and select Interpolate Vertex Elevations.
  6. Using the Select Feature Vertex tool review how the elevation at each vertex (refer to the video).


The second example uses survey data points and user defined points to create two breaklines that represent a deep pond in the channel bathymetry. Use the below steps and videos as a guide:

First (outer) breakline

  1. Using the Create Feature Arc tool digitise an arc around the pond. Note snap the arc ends to lowest elevation points (-2.30) at the sides of the pond (refer to the video).
  2. Repeat step 1 for the other side of the pond (refer to video).
  3. Using the Select Feature Arc tool hold shift and select the both arcs. Right click and select Redistribute Vertices.... Set the following attributes in the Redistribute Vertices:
    • From the drop down select Specified spacing.
    • Set an average spacing of 5. Select OK.
  4. Whilst the arc is still selected right click and select Smooth Arc(s).... Set the following attribute in the Smooth Arcs Tool dialog:
    • Set the Number of neighbors to 7.
    • Select OK.
  5. Again right click on the arc and select Interpolate Vertex Elevations.
  6. Using the Select Feature Vertex tool review the elevation at the vertices (refer to the video).


Second (inner) breakline

  1. Using the Create Feature Point tool digitise a point within the feature arcs that were created in the previous steps (refer to the video).
  2. Update the elevation value of point in the Z field to -3.0.
  3. Using the Create Feature Arc tool digitise an arc as circle that starts and ends at the new feature point (refer to the video).
  4. Using the Select Feature Arc tool hold shift and select the both arcs. Right click and select Redistribute Vertices.... Set the following attributes in the Redistribute Vertices:
    • From the drop down select Specified spacing.
    • Set an average spacing of 5. Select OK.
  5. Whilst the arc is still selected right click and select Smooth Arc(s).... Set the following attribute in the Smooth Arcs Tool dialog:
    • Set the Number of neighbors to 7.
    • Select OK.
  6. Again right click on the arc and select Interpolate Vertex Elevations.
  7. Using the Select Feature Vertex tool review the elevation at the vertices (refer to the video).

The third example has the breakline elevation assigned to the feature arc. Use the below steps and video as a guide:

  1. Using the Create Feature Arc tool digitise an arc from the pond to the bridge. Note do not snap the arc to any point data in the coverage (refer to the video).
  2. Use the Select Feature Arc tool to select and update the elevation value to -2.5.
  3. Right click on the arc and select Redistribute Vertices.... Set the following attributes in the Redistribute Vertices:
    • From the drop down select Specified spacing.
    • Set an average spacing of 5. Select OK.
  4. Whilst the arc is still selected right click and select Smooth Arc(s).... Set the following attribute in the Smooth Arcs Tool dialog:
    • Set the Number of neighbors to 7.
    • Select OK
  5. Again right click on the arc and select Interpolate Vertex Elevations.
  6. Using the Select Feature Vertex tool review the elevation at the vertices (refer to the video).


Once the map coverage has been prepared to create and assign elevations to the breaklines and associated vertices using the techniques above, it is then transformed into a scatter dataset. Use the below steps and video as a guide:

  1. Uncheck Sample_creek_survey_AHD_MGA56 Scatter Data.
  2. Right click on Breaklines_gen in the Map Data coverage. Select Convert > Map -> 2D Scatter.
  3. In the Map -> Scatter dialog set the Scatter Point Z-Value Source to Arc end points and vertex elevations. Leave the rest as the default and select OK.
  4. Uncheck Breaklines_gen map data.
  5. Use the Select Scatter Point tool to review the new Breaklines_gen Scatter Data.
  6. Right click on each scatter set and Remove.


The above demonstrated multiple techniques to build model breaklines. Review the breaklines included in the Base_Data and explore how the techniques discussed above can be applied to construct breaklines for the entire model domain. Use the below steps and videos as a guide:

  1. Zoom out and from the the Base_data folder check and select the map coverage Breaklines.
  2. Use the Select Feature Vertex to review how the channel thalweg elevations are interpolated via breaklines throughout the model area.

Create Model Bathymetry

This section demonstrates how to consolidate multiple scatter datasets into a single bathymetric surface. Specifically, breaklines, point survey data and gridded data are all combined to create a single continuous elevation surface. When merging multiple datasets it is crucial to ensure that all inputs share the same projection. In this example the data is represented in Australian Height datum AHD and UTM Zone 56 of the Geocentric Datum of Australia (GDA94) within Map Grid of Australia (MGA).

Use the below steps and videos to convert breaklines into a scatter set:

  1. Right click on Breaklines from the Base_data folder.
  2. Select Convert > Map -> 2D Scatter.
  3. In the Map -> Scatter dialog set the Scatter Point Z-Value Source to Arc end points and vertex elevations.
  4. Rename it Breaklines.
  5. Leave the rest as the default and select OK.
  6. Select Display Options and uncheck Scalar values.


A .csv is provided containing point survey data that covers the lake, canal and coastal regions. Use the below steps and videos to load the .csv as a scatter data:

Use the below steps and video to import the survey data:

  1. Select File > Open.... Navigate to Working\DEM\Lake_Coast_survey_AHD_MGA56.csv and Open.
  2. The File Import Wizard dialog will appear. Specify the following:
    • Check that the File import option are set to Delimited.
    • The Column delimiter Tab should be checked. Select Next >.
    • Select Finish.
    • Select OK on the warning Specify the projection for imported data.
    • The data is in the same projection as the project window. Select OK.
  3. Within the Project panel right click on Lake_Coast_survey_AHD_MGA56 > Zoom to Scatter and review data.


A combined offshore bathymetry and intertidal DEM at a grid size of 30m has been provided has been provided as a .tif file. Use the below steps and video to open and convert the gridded data into scatter data.

  1. Select File > Open.... Navigate to Working\DEM\Bathy_DEM_30m_AHD_MGA56.tif and Open.
  2. Right click on Bathy_DEM_30m_AHD_MGA56.tif and select Convert To > 2D Scatter. Accept the default name and select OK. Note it might take some time to convert the data to a scatter.
  3. Once complete remove Bathy_DEM_30m_AHD_MGA56.tif from GIS Data.
  4. Zoom into the newly created scatter data and use the Select Scatter Point to review the elevations.

Using the below steps and video to merge the scatter datasets:

  1. From the SMS tool bar select Scatter > Merge Sets.
  2. Under Select scatter sets to merge check all.
  3. Name the new scatter Bathy_001 and select OK
  4. Select OK if the error the Numerical limitation encountered arises and close the merge report. For information on the Scatter merge report refer to SMS Scatter .
  5. Uncheck the previously merged scatter datasets and review Bathy_001.
  6. Right click and Remove Breaklines, Lake_Coast_survey_AHD_MGA56 and Bathy_DEM_30m_AHD_MGA56 from the Scatter Data panel.

Now that the elevation datasets are in a single scatter (Bathy_001) it can be converted into a gridded raster. Use the below steps and video to convert the merged scatter data into a raster:

  1. Select Bathy_001 scatter set and right click. Select Convert > Scatter -> Raster.
  2. In the Interpolate to Raster dialog set the Cell size to 5.0 and select OK.
  3. Save the new raster into Working\DEM\Bathy_001.tif. Note it might take some time to convert the data to a raster.


To remove unnecessary data and reduce the file size trim the new raster using the below steps and video:

  1. Select Bathy_001.tif and right click. Select Convert To > Trimmed Raster.
  2. From the Coverage with polygons: drop down select Map Data/Base_data/Bathy_trim.
  3. Set the Output raster: path relative to Working\DEM\ call it Cudgen_Creek_bathy_001. Select OK.
  4. When the Trim Raster processing window is complete select OK. Note it might take some time for the trimmed raster to load into the SMS workspace.
  5. Right click and Remove Bathy_001.tif from the GIS Data panel.


By default the SMS Trim Raster tool produces a Tag Image File grid (.tif). As TUFLOW FV typically uses an ASCII grid (.asc) or binary grid (.flt) formats to assign bathymetry or topography the Cudgen_Creek_bathy_001.tif is exported as an .asc. Use the below steps and video to export the raster:

  1. Select Cudgen_Creek_001.tif and right click. Select Export.
  2. In the export window update the cell size to 5.0 and select OK.
  3. From the Save as type drop down select Arc Info ASCII Grid Files (*.asc) name the raster Cudgen_Creek_bathy_001.asc.
  4. Right click and Remove all raster files and scatter data from the project panel.

Congratulations on generating the bathymetry. This example highlighted important elevation data commonly used to create model bathymetry. In real-world applications, the model bathymetry would typically go through several iterations to accurately represent the elevations throughout the model domain. However, for the purposes of this tutorial, a single iteration was undertaken to simplify the process.

Constructing The Mesh

TUFLOW FV is designed for solving the Nonlinear Shallow Water Equation (NLSWE) on unstructured geometries and is commonly referred to as a flexible mesh model. Compared to structured rectilinear grids (i.e. fixed grids) the design of the flexible mesh tends to have a greater influence on model performance. Therefore, more time and effort should be spent preparing the model mesh geometry. Over the life cycle of a modelling project, a well assembled mesh will save time (both the modellers and the computers).

This section of the tutorial is designed to introduce key skills required developing a model mesh and specifically includes:

  • Construct the in channel mesh.
  • Construct the intertidal mangrove mesh.
  • Construct the ocean mesh.

Building The In Channel Mesh

The mesh in this example uses high resolution quadrilaterals to capture the in-channel hydrodynamics. For demonstration purposes, meshing will be undertaken downstream of the bridge to the estuary entrance only. However, the same meshing techniques can be applied to other channelised areas of the model domain. Specifically this section demonstrates how to:

  • Run TOPAZ.
  • Create bank lines.
  • Edit bank lines.
  • Define the downstream bridge opening.
  • Use blended arcs to define smooth bank lines.
  • Generate a mesh.

The SMS topographic preprocessor TOPAZ helps to guide mesh development as it allows the extraction of topographic features from the DEM such as the channel center line and banks. To maintain continuity in the tutorial, a separate topo-bathymetric raster has been provided for running the TOPAZ processor. However, in real-world studies, modelers should always develop the mesh using the model bathymetry.

Use the following steps and video to open the data and run Topaz:

  1. Select File > Open.... Navigate to Working\DEM\DEM_Catchment_5m_AHD_MGA56.tif and Open
  2. Right click on DEM_Catchment_5m_AHD_MGA56.tif and select Run TOPAZ. Note that the TOPAZ processing may take some time.
  3. Once complete select OK.
  4. Navigate to Working\DEM and two new files (.Tz and .TZlnv) will have been created.


The lower channel bathymetry has been provided and will help guide mesh generation in the lower estuary. Use the below steps and video to load and display the bathymetry:

Select File > Open.... Navigate to Working\DEM\Channel_Bathy_5m_AHD_MGA56.tif and Open. Specify the display as below.
  • Right click on Channel_Bathy_5m_AHD_MGA56.tif and select Zoom To Extents.
  • Right click on Channel_Bathy_5m_AHD_MGA56.tif and select Transparency....Update the transparency to 40%.
  • Right click on Channel_Bathy_5m_AHD_MGA56.tif and select Display Options....
  • Select Contour Options... from the Raster Display Options Dialog.
  • Check Specify a range.
  • Update the Max field to 1.0 and Min -2.0 .
  • Leave the Min field as default. Select OK > OK.


To create the Bank Lines we have provided the Stream and Guidance map data. SMS requires these to generate bank lines. MADDY TODO explain these further. Use the following steps and video to create the channel bank lines:

  1. In the project panel right click on Map Data > New Folder. Rename it Channel mesh.
  2. Under the Base data folder select Stream coverage. Right click and select duplicate.
  3. Move Streams (2) into the Channel mesh folder and rename it CL.
  4. From the provided Map Data select the Guidance coverage and use the following steps to copy the guidance Feature Point.
    • Using the Select Objects tool select the point at the estuary entrance. Right click and select Copy to Coverage....
    • From the dialog select CL coverage and OK.
  5. The copied feature point will appear in the CL coverage.


Now that the stream line and guidance point are within the same coverage bank lines can be created using the following steps and video:

  1. Using the Select Objects tool hold Ctrl > drag the curser over the the arc in the CL coverage.
  2. Now holding Shift select the guidance point that was copied into this coverage. Right click and select Extract Banks....
  3. From the Extract Features dialog update the following:
    • From the Use the depth drop down select Closest to centerline.
    • Set the Distance from Centerline maximum to 125.0.
    • Update the Output Coverage name to Channel_mesh.
  4. Select the new Channel_mesh coverage and right click and select Type > Generic > Mesh Generator.


The Break walls coverage has been provided to focus on building the in channel mesh. Use the following steps and video to copy the break walls into the Mesh coverage:

  1. Under the Base data folder select the Breakwalls coverage.
  2. Using the Select Objects tool click and drag the cursor across the nodes, vertices, arcs and polygons within the Breakwalls coverage (refer to video).
  3. Right click and select Copy to Coverage....
  4. From the dialog select Channel_mesh and OK. The breakwalls are now represented in the Mesh coverage.
  5. Use the Select Feature Point tool to snap the bankline feature arcs to the breakwall arcs (refer to video).

In this section of the tutorial, the focus will be on modifying and reviewing the lower estuary channel only. However in a real world example the modeler would review and refine the entire mesh. To accurately represent the estuary channel we need modify the bank lines using the DEM and aerial imagery as guides. In this section we will delete unnecessary vertices and use the SMS tools redistribute vertices and to create a smooth arcs that are later used to generate the mesh. It is recommended to minimise manual redistribution of vertices.

Use the following steps and videos to as a guide to edit the banks:

1. Turn on the DEM and aerial. Use both datasets to visualise where the channel banks are.
2. Starting at the left bank use the Select Feature Vertex to delete unnecessary vertices so that the channel is adequately represented. You may need to move some vertices into place. Use the below video as a guide.


3. Repeat steps 1-2 for the right bank and use the below video as a guide:


Use the below steps and video to redistribute the vertices and smooth the the channel bank lines:

4. Using the Select Feature Arc tool hold shift and select both arcs.
5. Right click and select Redistribute Vertices....
6. Set the following attribute in the Redistribute Vertices:
  • From the Specify drop down select Specified spacing.
  • Set an average spacing of 5.
  • Check Use cubic spline and select OK.
7. Whilst both arcs are still select right click and select Smooth Arc(s).... In the Smooth Arcs Tool dialog set the Number of neighbors to 7. Leave the rest as the default and select OK.


Some sections of the channel may not be well defined. Repeat steps 1-7 until the channel is well defined. Use the below video as an example.


The following section outlines meshing techniques to resolve hydraulic flow through the downstream bridge opening. Refer to the aerial image as a spatial reference and follow the below steps and videos:

1. Select Create Feature Arc and digitise a new arc using the footpath on the bridge as a guide (refer to the video).

Now add two new internal arcs to resolve the bridge opening.

  1. Using the Create Feature Arc tool digitiise an internal arc on the left bank. Start from the bridge arc and digitise towards the left bank (Refer to video).
  2. Repeat the same for the right bank (Refer to video).

Redefine the bank lines use the below steps and videos:

  1. Using the Select Feature Arc select and right click on the arc along the bridge and select Redistribute Vertices.... Set the following attributes:
    • From the Specify drop down select Number of Segments.
    • Set the number of segments to 4.
    • Select OK.
  2. Select and delete both outer arcs.
  3. Using the Select Feature Point select the remaining nodes. Right click and select Nodes <-> Vertices.
  4. Using the Select Feature Arc tool hold shift and select both arcs. Right click and select Redistribute Vertices....Set the following attributes in the Redistribute Vertices:
    • From the Specify drop down select Specified spacing.
    • Set an average spacing of 5.
    • Check Use cubic spline and select OK.
  5. Whilst both arcs are still selected right click and select Smooth Arc(s).... In the Smooth Arcs Tool dialog set the Number of neighbors to 7. Leave the rest as the default and select OK.


The lower channel of the estuary is now delineated by the bank lines. Use the following steps and videos to define and generate a smooth mesh:

  1. Using the Select Feature Arc tool hold shift and select both arcs. Right click and select Blend Arcs.
  2. Select the new blended arc. Right click and select Redistribute Vertices....Set the following attributes in the Redistribute Vertices:
    • From the Specify drop down select Specified spacing.
    • Set an average spacing of 20.
    • Check Use cubic spline and select OK.
  3. Whilst the arc is still selected right click and select Smooth Arc(s).... In the Smooth Arcs Tool dialog set the Number of neighbors to 1. Leave the rest as the default and select OK.
  4. Hold shift and select the blended arc (noting the arc ID in the bottom commentary of the SMS window) and the left bank arc (note the Arc ID). Right click and select Redistribute Vertices....Set the following attributes in the Redistribute Vertices:
    • From the Specify drop down select Source Arc.
    • Update the Source Arc with the blended arc ID.
    • Update the Target Arc with the bank arc ID
    • Check Use cubic spline and select OK.
  5. Repeat Step 4 on the right bank line arc.
  6. Delete the blended arc.


Use the below steps and video to generate the mesh:

  1. From the workspace toolbar select Feature Objects > Clean.... In the Clean Options dialog set the following:
    • Set Snap nodes and vertices to All nodes.
    • Set Clean coverage to All arcs and select OK.
  2. From the workspace toolbar select Feature Objects > Build Polygons.
  3. Using the Select Feature Polygon tool select the channel polygon. Right click and select Polygon Attributes....
  4. In the 2D Mesh Polygon Properties dialog set the Mesh type to Patch (quadrilaterals). Select OK.
  5. Right click on the Channel_mesh coverage and select Convert > Map -> 2D Mesh
  6. Rename the mesh Channel_mesh and select OK.
  7. Uncheck any open Map Data and review the mesh. Delete the mesh when complete.


Building The Mangrove Mesh

This example uses triangles to mesh and capture intertidal hydrodynamics within mangrove areas. For demonstration purposes, meshing of the mangrove area will be undertaken in two intertidal regions upstream of the bridge. The same meshing techniques can be applied to other intertidal areas throughout the model domain. Specifically this section demonstrates how to:

  • Identifying and digitizing intertidal areas in the mesh.
  • Editing paving (triangles) polygons and merge triangles.
  • Generating a mesh.

A map coverage template for meshing the intertidal mangrove areas has been provided for demonstration purposes. Use the following steps and video to duplicate the template data and set up the workspace:

  1. In the project panel right click on Map Data > New Folder. Rename it Mangrove mesh.
  2. Under the Base data folder select Mangrove_mesh_template coverage. Right click and select duplicate.
  3. Move Mangrove_mesh_template (2) into the Mangrove mesh folder and rename it Mangrove_mesh.
  4. Zoom into the bridge at the lower estuary. Note in the template the bank areas downstream of the bridge have been included.
  5. Check on the Channel_Bathy_5m_AHD_MGA56. Right click and select Display Options....Set the below options:
    • Select Contour Options... from the Raster Display Options Dialog.
    • Check Specify a range.
    • Update the Min field to -1.5 and the Max field to 3.0.
    • Leave the Min field as default. Select OK > OK.

First, create the mangrove area on the northern bank using the steps and video as a guide:

  1. Using the Create Feature Arc tool digitise the mangrove area on the northern bank. Remember to use the aerial and DEM as a guide (refer to video).
  2. Using the Select Feature Arc tool select the arc. Right click and select Redistribute Vertices....Set the following attributes in the Redistribute Vertices:
    • From the Specify drop down select Specified spacing
    • Set an average spacing of 5.
    • Check Use cubic spline and select OK.
  3. Whilst the arc is still selected right click and select Smooth Arc(s).... In the Smooth Arcs Tool dialog set the Number of neighbors to 7. Leave the rest as the default and select OK.
  4. Again Redistribute the vertices with the following attributes:
    • From the Specify drop down select Number of Segments.
    • Set the number of segments to 10.
    • Select OK.
  5. From the workspace toolbar select Feature Objects > Clean.... In the Clean Options dialog set the following:
    • Set Snap nodes and vertices to All nodes.
    • Set Clean coverage to All arcs and select OK.
  6. From the workspace toolbar select Feature Objects > Build Polygons.
  7. Using the Select Feature Polygon tool select the channel polygon. Right click and select Polygon Attributes....
  8. In the 2D Mesh Polygon Properties dialog set the Mesh type to Paving (triangles). Select Preview to view the paving elements. Select OK.


Create the mangrove area on the southern bank using the steps and video as a guide:

  1. Using the Create Feature Arc tool digitise the mangrove area on the northern bank. Remember to use the aerial and DEM as a guide (refer to video).
  2. Using the Select Feature Arc tool select the arc. Right click and select Redistribute Vertices....Set the following attributes in the Redistribute Vertices:
    • From the Specify drop down select Specified spacing
    • Set an average spacing of 5.
    • Check Use cubic spline and select OK.
  3. Whilst the arc is still selected right click and select Smooth Arc(s).... In the Smooth Arcs Tool dialog set the Number of neighbors to 7. Leave the rest as the default and select OK.
  4. Again Redistribute the vertices with the following attributes:
    • From the Specify drop down select Number of Segments.
    • Set the number of segments to 9.
    • Select OK.
  5. From the workspace toolbar select Feature Objects > Clean.... In the Clean Options dialog set the following:
    • Set Snap nodes and vertices to All nodes.
    • Set Clean coverage to All arcs and select OK.
  6. From the workspace toolbar select Feature Objects > Build Polygons.
  7. Using the Select Feature Polygon tool select the channel polygon. Right click and select Polygon Attributes....
  8. In the 2D Mesh Polygon Properties dialog set the Mesh type to Paving (triangles). Select Preview to view the paving elements. Select OK.

Now the mangrove areas are delineated in the Map Data the mesh can can generated. Use the following steps and videos to define and generate the mesh and merge any unnecessary triangles within the mesh:

  1. From the Map Data right click on Mangrove_mesh. Select Convert > Map -> 2D Mesh.
  2. Rename the new mesh Mangrove_mesh.
  3. From the workspace toolbar select Elements > Merge Triangles. Note this is undertaken to remove thin triangles from the mesh that can potentially slow model runtimes.
  4. Uncheck any open Map Data and review the mesh. Delete the mesh when complete.


Build Ocean Mesh

In this section generating the offshore model boundary is demonstrated. Using inbuilt SMS tools to increase model resolution on shore and decrease offshore. (Use secondary basis instead of calculator and try as one way for north and south). Say to them if they have a paid version use the calculator and link them to the SMS webpage on the tool

A map coverage template for meshing the offshore boundary has been provided for demonstration purposes. Use the following steps and video to duplicate the template data and set up the workspace:

  1. In the project panel right click on Map Data > New Folder. Rename it Ocean mesh.
  2. Under the Base data folder select Ocean_mesh_template coverage. Right click and select duplicate.
  3. Move Ocean_mesh_template (2) into the Ocean mesh folder and rename it Ocean_mesh.
  4. From the provided Map Data select the Coastline coverage and use the following steps to copy the feature arcs.
    • Using the Select Feature Arc tool select hold shift and select both arcs. Right click and select Copy to Coverage....
    • From the dialog select Ocean_mesh coverage and OK.


Use the following steps and video to set the onshore resolution using redistribution of vertices:

  1. Using the select feature arc select the northern coastal arc. Right click and select Redistribute Vertices....Set the following attributes in the Redistribute Vertices:
    • From the Specify drop down select Specified spacing.
    • Update the Average spacing to 150.
    • Update the Bias to 15.
    • Check Use cubic spline and select OK.
  2. Repeat the above steps for the southern coastal arc.


Use the following steps and video to define the offshore boundary arc and set the resolution:

  1. Using the Select Feature point tool hold shift and select the most northern and southern points (refer to video). Right click and select Define Domain. In the domain Options set the following:
    • Check Semi-circular and OK. Note if the semicircular arc is oriented inland, then select and delete it, repeat this series of steps, but check the Switch side checkbox in the Define domain dialogue.
  2. Using the select feature arc select the new offshore boundary arc. Right click and select Redistribute Vertices....Set the following attributes in the Redistribute Vertices:
    • From the Specify drop down select Specified spacing.
    • Update the Average spacing to 750.
    • Update the Bias to 3.
    • Check 2nd bias (0.01-100.0) and update to 3.
    • Select OK.
  3. From the workspace toolbar select Feature Objects > Clean.... In the Clean Options dialog set the following:
    • Set Snap nodes and vertices to All nodes.
    • Set Clean coverage to All arcs and select OK.
  4. From the workspace toolbar select Feature Objects > Build Polygons.



Now the mangrove areas are delineated in the Map Data the mesh can can generated. Use the following steps and videos to define and generate the mesh and merge any unnecessary triangles within the mesh:

  1. From the Map Data right click on Mangrove_mesh. Select Convert > Map -> 2D Mesh.
  2. Rename the new mesh Mangrove_mesh.
  3. From the workspace toolbar select Elements > Merge Triangles. Note this is undertaken to remove thin triangles from the mesh that can potentially slow model runtimes.
  4. Uncheck any open Map Data and review the mesh. Delete the mesh when complete.

Keep for later

3. Select File > Open.... Navigate to Working\DEM\DEM_Catchment_5m_AHD_MGA56.tif and Open. Specify the display as below:
  • Right click on DEM_Catchment_5m_AHD_MGA56.tif and select Transparency....Update the transparency to 40%.
  • Right click on DEM_Catchment_5m_AHD_MGA56.tif and select Display Options....
  • Select Contour Options... from the Raster Display Options Dialog.
  • Check Specify a range.
  • Update the Max field to 10.0 and uncheck Fill above.
  • Leave the Min field as default. Select OK > OK.

Feedback

If you have any queries, feedback or requests for new functionality you would like added to the tutorial modules, please feel free to get in contact with support@tuflow.com.

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Conclusion And Next Steps

Well done on completing Meshing Module 3. You have now learnt the skills to build a real-world coastal model mesh and generate bathymetry from multiple datasets.

Return to the Tutorial Introduction Page to complete further meshing and model build tutorials.

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