Daily DAX : Day 342 RADIANS

Power BI DAX RADIANS Function

Description

The RADIANS function in Power BI DAX converts an angle from degrees to radians. Many trigonometric calculations, such as those involving SIN, COS, or TAN, require angles in radians rather than degrees.

Syntax

RADIANS(number)

• number: The angle in degrees (required).

Return Value

The angle converted to radians (numeric value).

Use Case

The RADIANS function is useful in scenarios involving trigonometric calculations, such as:

• Calculating distances between geographic coordinates using the Haversine formula.
• Performing calculations in engineering or physics dashboards that involve angles.
• Creating visualizations that require trigonometric transformations.

Example

Suppose you have a column Degrees with an angle value of 180. You want to convert it to radians for use in a SIN calculation.

SineOfAngle = SIN(RADIANS(180))

Result: RADIANS(180) returns approximately 3.14159 (π radians), and SIN(RADIANS(180)) returns 0, since the sine of π radians is 0.

Practical Example: Haversine Formula

To calculate the distance between two geographic points (latitude and longitude), you need angles in radians. For example:

Distance = 
VAR Lat1 = RADIANS(Table[Latitude1])
VAR Lat2 = RADIANS(Table[Latitude2])
VAR Lon1 = RADIANS(Table[Longitude1])
VAR Lon2 = RADIANS(Table[Longitude2])
RETURN
    6371 * ACOS(
        COS(Lat1) * COS(Lat2) * COS(Lon2 - Lon1) + SIN(Lat1) * SIN(Lat2)
    )
    

This calculates the distance in kilometers between two points on Earth, using RADIANS to convert latitude and longitude from degrees to radians.

Notes

• The input number must be a numeric value representing degrees.
• The function is often paired with trigonometric functions like SIN, COS, or TAN.
• If the input is non-numeric, it will result in an error.