Viz.Heatmap

Renders a heatmap as an SVG data URI showing data density using kernel density estimation

Kernel Density Estimation (KDE)

KDE is a statistical method that estimates the probability density function of your data by placing a "kernel" (typically a normal distribution) at each data point. The heatmap visualizes data density across the range, creating smooth gradients that reveal patterns and concentrations in your dataset.

Key Parameters:

• Samples: Controls the resolution of the density calculation (higher = smoother, but slower performance)

• Bandwidth: Controls the smoothing level - smaller values create sharper peaks around data points, larger values create broader, smoother distributions

SyntaxExampleDefinition

DaxLib.SVG.Viz.Heatmap( axisRef, measureRef, color, width, height )

Parameter	Type	Required	Default	Description
axisRef	ANYREF EXPR			Axis reference column
measureRef	NUMERIC EXPR			Measure expression
color	STRING		BLANK()	Optional color for high density areas. Defaults to Power BI theme color
width	INT64		120	Optional: SVG width. Defaults to 120
height	INT64		48	Optional: SVG height. Defaults to 48

STRING SVG Heatmap

DaxLib.SVG.Viz.Heatmap(
    Products[Product],  // axisRef
    [Total Cost],       // measureRef
    ,                   // color
    200,                // width
    60                  // height
)
// Returns an SVG data URI with an embedded heatmap
// Set as a measure with DataCategory = "ImageUrl"

function 'DaxLib.SVG.Viz.Heatmap' =
        (
            axisRef: ANYREF EXPR,
            measureRef: NUMERIC EXPR,
            color: STRING = BLANK(),
            width: INT64 = 120,
            height: INT64 = 48
        ) =>

            VAR _Marks =
                DaxLib.SVG.Compound.Heatmap(
                    0, 
                    0, 
                    width, 
                    height,
                    axisRef, 
                    measureRef, 
                    50, 
                    1, 
                    color
                )

            RETURN
                IF( NOT ISBLANK( _Marks ), DaxLib.SVG.SVG( "100%", "100%", _Marks, "0 0 " & width & " " & height ) )