Eye4Software Hydromagic

  Hydrographic Survey Software


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Generating a reference matrix from CAD or vector maps

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


CAD drawing

This is perhaps the easiest way to create a reference matrix (DTM or digital terrain model), provided that an AutoCAD DXF or MicroStation design of the area is available (and of course, contains elevation information). From the vectors collected from the CAD file, a TIN model is generated from which heights are calculated. When comparing the matrix created from a sounding, with a matrix created from a CAD drawing, we can calculate the amount of material which has to be removed or added in order to get the result as defined in the CAD drawing (dredging volumes). A sample CAD design of how to construct a basin is displayed below:

Example of an AutoCAD DXF drawing containing elevation lines
Example of an AutoCAD DXF drawing containing elevation lines.


Starting the tool

To start the conversion, please make sure you have imported the CAD drawing (vector map) into the project. When it displays correctly in the map view, right click on the loaded DXF or DGN CAD file in the "Project Explorer", and select the "Export to Matrix..." option. This will launch the "matrix from vector" tool."In this tool you can select the CAD file as well the name(s) of the layer(s) you want to include in the calculation.

Select the convert to matrix option from the maps folder
Select the "Convert to Matrix..." option from the context menu.


Using the conversion tool

Use the drop-down box to select the map layer which contains the features which contain the elevation information you wish to use in the matrix generation. It is recommended to draw these lines in a separate layer in your file. Click the "Select..." button to select the layers to include in the calculation.

Browse for an AutoCAD DXF file and select the DXF layers to include.
Browse for an AutoCAD DXF file and select the DXF layers to include.

Matrix spacing

Set the required spacing. Please note that when using the volume calculation using matrices, this spacing should be equal to the one used in the matrix generated from the sounding, otherwise it cannot be used in volume calculations.

Clipping area

Select which area or boundary will be used to indicate the clipping area of the matrix generated from the AutoCAD file. You can for instance convert the outer polyline to a boundary. When you want to disable clipping, select the default option "NONE".

Output file

Click the second browse button to select a folder and file name for the generated matrix. The matrix is saved as a binary file containing all the XYZ pairs calculated by this tool using a TIN model.


Starting generation

When all options have been set, click the "OK" button to start the matrix generation process. The software will collect all usable vertices (coordinates) from the AutoCAD drawing and creates a TIN model of the data to calculate the matrix with fixed cell sizes. After generation, the matrix will be loaded 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 generated matrix in 2D.
The generated matrix in 2D.

The generated matrix in 3D.
The generated matrix in 3D.


Troubleshooting

When the matrix failed to generated or display, please check the following:

You can check the activity view tab processing for errors.
You can check the "Processing" activity view tab for errors..

Video Tutorial: Generate a matrix from CAD or GIS objects

The following video tutorial shows how to generate a reference matrix or DTM from a loaded AutoCAD file.
It also shows how to create a boundary from DXF.