Add support for fixed Y-axis min/max values in Dataviz plots

Hello
Currently, in Lizmap Dataviz (QGIS Plugin and Web Client), the Y-axis of scatter and line plots is automatically scaled based on the data values.

It is not possible to set a fixed minimum and maximum value for the Y-axis in the JSON configuration. This makes it difficult to compare multiple plots with the same scale or to create standardized visualizations.

Proposed feature:

• Add support for optional y_axis_min and y_axis_max parameters in the JSON configuration for each trace or plot.
• When specified, these values should override the automatic scaling of the Y-axis, while still keeping all other Dataviz features intact.
• Ideally, the feature should be available for scatter and line plots, both in the plugin GUI and when editing the JSON configuration directly.

Use cases:

• Standardizing Y-axis across multiple plots for comparison.
• Avoiding misleading visualizations when datasets have very different ranges.
• Enabling consistent dashboards for monitoring environmental, engineering, or geospatial data.

Thank you for considering this enhancement. It would greatly improve usability and flexibility of Lizmap Dataviz.

Best regards
Andreas

[mdouchin]

Thanks for this issue. I completely understand the need to better control the rendering of plots.
What about if Lizmap would allow overriding the plot configuration, as we can now override the layout with JSON ?

This would allow power users to adapt plots based on their specific needs, without the need for lizmap-plugin to add many configuration options for each plot type and context ?