Generating a Reference Matrix from Sections

A reference matrix that can be used to perform volume calculations can be created from:

• one or more soundings;
• shoreline information;
• collection of sections, also known as a channel design;
• a vector chart which contains 3D vectors.

Channel design

When comparing the matrix created from a sounding with a matrix created from a channel design, we can calculate the amount of material which must be (re)moved to achieve the same result as in the channel design. A channel design can created in Hydromagic or using CAD software like AutoDesk AutoCAD and others.

A channel design can be created using cross sections.

Generate the matrix

To start creating a matrix from the channel design, right-click the 'Sections' folder in the 'Project Explorer', and select the "Generate Matrix..." options as shown below:

Select the generate matrix option from the sections folder.

After selecting this option the "Generate Matrix from Sections" dialog will be displayed, as shown in the image below:

Generate matrix from selected cross sections.

Sections

Select which sections you want to include in the matrix calculation. In most cases, you select all sections, which can be done by clicking the 'Select All' button. To deselect all sections, click the "Select None" button. To select only sections that are set as visible in the project, click 'Select Visible'.

Matrix Spacing

Set the required matrix spacing. Please note that when performing volume calculations using matrices, this spacing should be equal to the one used in the matrix generated from the sounding.

Clipping and shorelines

Select which area or boundary will be used to indicate the clipping area of the matrix generated from the sections. This value is required.

Filename

Click the 'Browse' button to select a folder and filename for the generated matrix. The matrix is saved as an ASCII file containing all the XYZ pairs calculated by this tool using TIN.

Starting generation

When all parameters have been set, the matrix will be calculated and added to the project. During the generation process, a progress bar will be shown in the status bar. When finished and loaded, you will see something similar to the image below:

The resulting matrix using the cross sections as shown in the image above.