Day 11: Visualisations — Core Charts

Bar/Column Chart: for comparing values across categories. Line Chart: for trends over time. Card: for displaying a single KPI value prominently. Slicer: for user-controlled filtering. Table/Matrix: for detailed tabular data with row/column groupings. Donut/Pie Chart: for part-to-whole relationships (limited to 4-5 categories). Map visuals: for geographic data. Scatter Chart: for correlations between two measures. These cover 90% of real business reporting needs. Know when to use each — choosing the wrong chart type is a common mistake in interviews.

In Report View: click an empty area of the canvas → click the visual type in the Visualisations pane (right side) → the visual appears on the canvas → drag fields from the Fields pane (far right) to the visual's field wells (Axis, Values, Legend, Tooltips, etc.). Or: select your data fields first by checking them in the Fields pane → Power BI automatically suggests and creates an appropriate visual. Resize by dragging corners. Move by dragging the title bar. Format with the Format pane (paint roller icon).

A slicer is a special visual that acts as a filter control on the report page — users click items to filter all other visuals on the page. Add a slicer: insert Slicer visual → drag a dimension field (Region, Category, Year) to the Field well. Style options: List (all options as clickable items), Dropdown (compact), Between (for date ranges), Slider (for numeric ranges). Slicers filter all visuals on the same page by default. Use "Edit interactions" to control which visuals a slicer does and does not filter.

A Table visual shows flat tabular data — rows of data with column headers, no grouping or aggregation hierarchy. A Matrix visual is like a Pivot Table — it has Rows, Columns, and Values fields that create a cross-tab layout with subtotals and grand totals. Rows and Columns can have multiple fields for drill-down hierarchies. Use Table for detailed line-item data. Use Matrix for cross-tabulation (Revenue by Region and Product Category), for showing totals at multiple levels, and for any data that benefits from row/column groupings.

Select the chart → Format pane (paint roller) → expand "Data labels" section → toggle On. Configure: position (inside end, outside end, centre), value type (value, percentage, both), font size, colour, display units (auto, thousands, millions). For bar charts showing revenue: set display units to "Millions" with 1 decimal place so ₹1,25,00,000 shows as "₹12.5M". For percentage charts: show the percentage alongside the absolute value by adding a tooltip measure. Clean data labels make charts self-explanatory without needing a separate data table.