Group a Time Series for Plotly Without Tangling the Main View

Suggested cover: a monitoring view dominated by a clean time-series line chart with timestamp labels across the bottom.

The line chart becomes easier to scan when the layout and the series are not fused together

The chart block is already concise, but it still contains several steps at once: the two-column split, the chart subheader, the grouped series and the render call. Splitting those into smaller slices makes the left-side chart easier to reconstruct without changing its source logic.

This keeps the same Streamlit chart flow, but distributes it across more compact blocks that each answer one question at a time.

Term	Meaning	Why it matters
Column split	The two-column layout that holds the charts.	It establishes the side-by-side visual structure used later in the page.
Grouped series	The time-indexed intensity aggregation.	It is the actual dataset consumed by the line chart.
Render call	The Streamlit chart function for the grouped series.	It shows where the shaped series finally turns into a visual.

The chart section starts with the column layout

            col5, col6 = st.columns(2)

The two chart columns are easier to place when their layout line sits alone.

The left column opens with its own heading

            with col5:
                st.subheader("Traffic Intensity Over Time")

The left chart title becomes much easier to read when it is not bundled with the grouping expression.

                chart_data = df.set_index('time').groupby('time')['intensity'].sum()

The grouped series is now isolated, which makes the chart's data shape easier to verify before rendering.

                st.line_chart(chart_data)

The final render call remains a one-line destination for the grouped series.

• The chart layout is easier to rebuild because the column split now stands on its own.
• The grouping expression is visible as a separate step instead of hiding inside the render call.
• The final line chart call stays direct and easy to spot.

A chart is easier to trust when its layout, series and render call can each be read as separate steps.