Title "Undefined" when creating a linechart with mesa.visualization.modules.ChartModules

[Sabi89129]

I used the following code for creating a line chart with mesa.visualization.modules.ChartModules.
Unfortunately the color is very weak and the tilte is shown as "Undefined".

class DiseaseModel(Model):
.
 def __init__(self,...):
      # Add datacollector for linechart
      self.datacollector = DataCollector(
      model_reporters={"Infected": get_num_infected_agents})

.
.
  def step(self):
        self.schedule.step()
        self.datacollector.collect(self)

infected_chart = visualization.ChartModule([{"Label":"Infected","Color":RED_COLOR}])
server = visualization.ModularServer(DiseaseModel, [grid,infected_chart],....)

[rht]

Thank you for reporting. I confirm this is a bug in the frontend, where the "Label" actually has to be lower case "label" in order for the label to show up. According to https://www.chartjs.org/docs/3.6.2/charts/line.html, it has to be lower case. But currently in the code, it is hardcoded to expect "Label": https://github.com/projectmesa/mesa-viz-tornado/blob/77c80052d471cc4c830192b5a63824b8c79d69ea/mesa_viz_tornado/modules/ChartVisualization.py#L79.

This should be a quick fix.

[rht]

As with the weak color, it's because the opacity is hardcoded to 0.1: https://github.com/projectmesa/mesa-viz-tornado/blob/77c80052d471cc4c830192b5a63824b8c79d69ea/mesa_viz_tornado/templates/js/ChartModule.js#L23.

Anyway, I recommend using the new pure Python frontend in mesa.experimental instead, which is based on Matplotlib, and allows you to avoid this problem altogether. See the app.py in https://github.com/projectmesa/mesa-examples/tree/main/examples/schelling_experimental.

[rht]

With mesa.experimental.JupyterViz, you can only plot 1 line per plot. If you want multiple lines in 1 plot, see https://github.com/projectmesa/mesa-examples/blob/main/examples/virus_on_network/app.py instead.