SAMPLEAXISWITHLOCALMINMAX

A line chart's sample of a table: each bin's least and greatest values per series; past the size asked, Power BI Desktop's own bins may differ.

Group: Window and visual calculations. Compatible with DAX.

Syntax

SAMPLEAXISWITHLOCALMINMAX ( <Size>, <Table>, <Axis>, <Measure> [, <Measure>] …, <MinResolution> [, <DynamicSeries>] … [, <DynamicSeriesSelectionCriteria>] [, <DynamicSeriesSelectionOrder>] [, <MaxResolution>] [, <MaxDynamicSeries>] [, <MaxIterations>] )

Parameter	Type	Description
`Size`	Whole number	About how many rows to keep.
`Table`	Table	The chart's points: one row per point.
`Axis`	Column	The column along the chart's horizontal axis: numbers or dates.
`Measure`	Column repeatable	A column of the values drawn: the sample keeps the rows with each bin's smallest and largest value.
`MinResolution`	Whole number	The fewest points to keep for each series across the axis.
`DynamicSeries`	Column optional, repeatable	Columns that make the series, one line each.
`DynamicSeriesSelectionCriteria`	Keyword optional	`NONE` or `ALPHABETICAL`: the order of the series when not all of them fit.
`DynamicSeriesSelectionOrder`	Keyword optional	`ASC` or `DESC` for that order.
`MaxResolution`	Whole number optional	The most points to keep for each series.
`MaxDynamicSeries`	Whole number optional	How many series to keep at most.
`MaxIterations`	Whole number optional	How many tries at a bin width that brings the rows near Size.

Returns

Table. Rows of the table, in its own order: all of them, or a sample that keeps each bin's lowest and highest points.

Remarks

Power BI's line charts use it to thin out a long series of points without losing its peaks and dips. Report authors seldom write it by hand.
When the table has no more rows than Size, it comes back whole; a Size of 0 or less gives an empty table.
Otherwise the axis is cut into bins of equal width, and for each series the rows holding a bin's lowest and highest value are kept; the number of bins is tried until the rows come near Size.
Rows whose axis value is blank are left out of a sample.

Compared with DAX

Past Size rows, OpenBI's bins are its own: Power BI may keep other rows of the same table. Up to Size rows, both return the table whole.

Examples

Few enough rows: the whole table

EVALUATE
VAR Days =
    DATATABLE (
        "Day", INTEGER, "Liters", INTEGER,
        { { 1, 40 }, { 2, 55 }, { 3, 38 }, { 4, 61 }, { 5, 70 }, { 6, 52 }, { 7, 45 }, { 8, 66 } }
    )
RETURN
    SAMPLEAXISWITHLOCALMINMAX ( 10, Days, [Day], [Liters], 10 )
ORDER BY [Day]

Day	Liters
1	40
2	55
3	38
4	61
5	70
6	52
7	45
8	66

Eight days thinned to four

Two bins, days 1 to 4 and 5 to 8: each keeps its lowest and its highest day.

EVALUATE
VAR Days =
    DATATABLE (
        "Day", INTEGER, "Liters", INTEGER,
        { { 1, 40 }, { 2, 55 }, { 3, 38 }, { 4, 61 }, { 5, 70 }, { 6, 52 }, { 7, 45 }, { 8, 66 } }
    )
RETURN
    SAMPLEAXISWITHLOCALMINMAX ( 4, Days, [Day], [Liters], 4 )
ORDER BY [Day]

Day	Liters
3	38
4	61
5	70
7	45

Days 3 and 4 are the first bin's low and high, days 7 and 5 the second's.

SAMPLE, SAMPLECARTESIANPOINTSBYCOVER, TOPN.

Last updated 3 November 2026 · OpenBI Studio 0.3.74