13. TUFLOW CATCH JSON

13.1 Loading¶

CATCH result files can be loaded by dragging and dropping the .tuflow.json file into the QGIS Map Canvas from a file explorer or from the Browser Panel.

The temporal and maximum results for each data type can then be toggled on and off using the "scalar" and "vector" buttons in the Datasets tab within the Styling Panel. The Styling Panel can be opened/closed by pressing F7 or Ctrl+3 on the keyboard.

Note: The .tuflow.json file represents both TUFLOW FV results. Certain result types may only be available for one of the model results.

13.2 Coordinate Reference System¶

The CATCH JSON format does not support storing coordinate reference system (CRS) information. If there is a projection.prj file in the same directory as the .tuflow.json file, then TUFLOW Viewer will attempt to read the CRS information from this file. If there is no projection.prj file, then TUFLOW Viewer will default to using the CRS of the QGIS Project.

The CRS can be changed by right-clicking the layer in the Layers Panel and navigating to Layer CRS ► Set Layer CRS....

13.3 Reference Time¶

The reference time determines the isodate values shown for the "Animation Range" in the Temporal Controller window. The CATCH result reference time is defined in the .tuflow.json file and can be edited by the user if needed.

The reference time can be changed in the Temporal tab in the Layer Properties.

The "Set to Full Range" button on the Temporal Controller window will update the animation range.

13.4 Styling¶

CATCH results files can be styled in a very similar way as raster layers in QGIS. This can be done by pressing F7 or Ctrl+3 on the keyboard to open the Styling Panel for the active layer. The opacity and colour shading of the scalar outputs can be modified from the Contours tab of the Styling Panel.

The velocity vectors can be styled as arrows, streamlines, traces, or wind barbs. The most common way (and the default style) is as vector arrows. The size of the arrow can be scaled several different ways and there are also options to change features such as the line width, colour, arrow head size etc. All of these vector styling options can be found within the "Vectors tab" of the Styling Panel.

Detailed guidance on the contour and vector styling options for mesh data in the Styling Panel can be found in the QGIS User Manual.

13.4.1 Default Styling¶

The styling on the active result type can be set as the default for that result type. This can be done by right-clicking the layer in the Layers Panel and navigating to the TUFLOW Viewer menu. For example, if the default style for "Bed Elevation" is saved, then each time an CATCH result file is loaded, the "Bed Elevation" result type will be styled using the saved default style.

The options in the menu are:

Save Colour Ramp as Default: This will save the colour ramp for the active result type, but not the exact colour to value mapping. This means that the colour ramp will be applied to the new result type, but the stop values will not be changed.
Save Colour Map as Default: This will save the exact colour to value mapping for the active result type. This means that the colour ramp and the stops will be applied to the new result type.
Save Vector Settings as Default: This will save the vector settings for the active result type. This includes the symbology, colouring method, arrow length, and other arrow properties etc.
Load Default Style: Options to load the default scalar or vector styles are also available. This will apply the saved default style to the active result type. The load default style option may not update the Styling Panel to reflect the loaded default style.