TUFLOW Viewer Matplotlib Font Error - Revision history

Emilie Nielsen at 01:56, 8 January 2026

2026-01-08T01:56:28Z

← Older revision		Revision as of 11:56, 8 January 2026
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	<li> If the problem persists, try deleting all the fontlist files in the folder.		<li> If the problem persists, try deleting all the fontlist files in the folder.
	</ol>		</ol>


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Ellis Symons at 08:57, 5 March 2025

2025-03-05T08:57:40Z

← Older revision		Revision as of 18:57, 5 March 2025
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	: [[File: file_explorer_mpl_cache_location.PNG]]		: [[File: file_explorer_mpl_cache_location.PNG]]
	<li> Try opening TUFLOW Viewer (you should not need to restart QGIS, however if it still doesn't work then restarting QGIS will be worth trying)		<li> Try opening TUFLOW Viewer (you should not need to restart QGIS, however if it still doesn't work then restarting QGIS will be worth trying)
			<li> If the problem persists, try deleting all the fontlist files in the folder.
	</ol>		</ol>

Ellis Symons: Created page with "This page describes how to fix TUFLOW Viewer if you get the following error (or similar). Unfortunately this is a bug with the plotting library TUFLOW Viewer uses (matplotlib)..."

2023-04-27T12:03:38Z

Created page with "This page describes how to fix TUFLOW Viewer if you get the following error (or similar). Unfortunately this is a bug with the plotting library TUFLOW Viewer uses (matplotlib)..."

New page

This page describes how to fix TUFLOW Viewer if you get the following error (or similar). Unfortunately this is a bug with the plotting library TUFLOW Viewer uses (matplotlib) and is due to an issue with its cached data.
<pre>
ValueError: Failed to find font DejaVu Sans:style=normal:variant=normal:weight=normal:stretch=normal:size=10.0, and fallback to the default font was disabled
</pre>
To fix this issue, the matplotlib cache data will need to be deleted. The steps below describe how to do this:
<ol>
<li> Open QGIS
<li> Open the Python interpreter
: [[File: qgis_python_interpreter_tool_button.PNG]]
<li> In the python interpreter type the following commands:
<pre>
import matplotlib
print(matplotlib.get_cachedir())
</pre>
:[[File: qgis_python_interpreter_mpl_cache_location.PNG]]
<li> This will print the matplotlib cache directory
<li> In this directory, delete the fontlist-v330.json file
: [[File: file_explorer_mpl_cache_location.PNG]]
<li> Try opening TUFLOW Viewer (you should not need to restart QGIS, however if it still doesn't work then restarting QGIS will be worth trying)
</ol>