Overview of QGIS 3.12 Mesh Features

JANUARY 15, 2020 crayfish mdal news qgis

Ready for 3D meshes, vector streamlines or contour export?

The releases of QGIS 3.12, MDAL 0.5.0 and Crayfish 3.2.1 are planned for end of February 2020. We are proud to present you few of upcoming features we implemented for this release:

  • vector trace animation
  • 3D stacked meshes
  • mesh calculator enhancements
  • export contours
  • various smaller enhancements (reference time support, resampling, export plot data, mdal_translate utility)

If you are hesitant to wait till end of February, feel free to get nightly build and test it out!

Support for vector trace animation and streamlines (QGIS)

Last feature from QGIS 2.x/Crayfish 2.x series that was not ported to QGIS 3 is finally available. You would be able to visualize streamlines and particles for vector datasets in mesh layers. In QGIS main menu, under Mesh>Crayfish>Export Trace you are also able to export animation with the particle traces to various video formats

Trace animation

This feature was funded by TUFLOW

Support for 3d Stacked Meshes (e.g. TUFLOW FV format)

MDAL and QGIS now supports 3D Stacked Meshes, particularly for TUFLOW-FV format. For this release, you need to choose appropriate averaging method in the QGIS interface and you are able to browse the data similarly to any other 2D dataset. 3d stacked

In Crayfish 3.2.1, you can create plots of the profile showing the variation along Z-axis.

3d stacked plot

The technical description can be found in the following QEP

This feature was funded by TUFLOW

On the fly resampling of data defined on faces to vertices

For datasets defined on faces, one can choose to interpolate data to vertices with neighbour average method. When no data interpolation method is chosen, each pixel on a single face has a single value/color. With data on vertices, the rendering for each pixel is interpolated from the values on the vertices, making smoother figures.

Use mesh contours styling panel to switch between the data interpolation methods.

No Mesh Data Resampling Dialog Mesh Data Resampling Mesh Data Resampling Dialog

This feature was funded by Austrian Ministry of Agriculture, Forestry, Environment and Water Management

Smooth export of the contours (Crayfish processing algorithm)

We have implemented a new algorithm in QGIS’s analysis library to export directly contour lines and polygons. The method is not based on GDAL as it was in the Crayfish 2.x releases. It is both faster and with smoother shapes, matching rendered images from QGIS. You can find the new processing algorithm in Crayfish processing toolbox.

Mesh Contours

This feature was funded by Austrian Ministry of Agriculture, Forestry, Environment and Water Management

Support of datasets defined on faces in QGIS Mesh Calculator

From QGIS 3.12 you can use mesh calculator for all datasets, both defined on faces and vertices. Additionally, it allows users to store the result of mesh calculator under different name or format. This allows for example to work with FLO-2D or HEC-RAS data in the QGIS mesh calculator

This feature was funded by Austrian Ministry of Agriculture, Forestry, Environment and Water Management

Support for reference time (QGIS)

For various dataset type, for example GRIB and NetCDF, the reference time in QGIS time settings dialog is prepopulated from the raw data and does not need to be set manually. Also we fixed various bugs related to time parsing, so in QGIS 3.12 it should be possible to format and show your time in plots/animations in proper way.

Reference Time

This feature was funded by TUFLOW

Support for conversion of 2dm to UGRID mesh (mdal_translate utility)

MDAL library now has a new utility: mdal_translate. For now, use can use the utility to convert text-based 2dm mesh definition files to UGRID NetCDF/HDF5 binary-based format and save up to 80% disk and speed up loading of your mesh by similar amount.

This feature was funded by TUFLOW

Support for export of 2D plot data (processing)

With Crayfish 3.2.1 you can export your time series or cross section raw dat to CSV format for further processing.

This feature was funded by Lutra Consulting


Posted by Peter Petrik, Saber Razmjooei