# Vector Field function

## Overview

The Vector Field function is used to composite and convert two rasters into a two-band raster that is of either data type Magnitude-Direction or data type U-V.

## Notes

If the Input Data Type parameter is Magnitude-Direction, you also need to specify the Angular Reference System. parameter.

The U value is sometimes referred to as the zonal velocity or velocity along latitudinal lines. The V value is sometimes referred to as the meridional velocity or velocity along longitudinal lines.

### Conversion between U-V and Magnitude-Direction

The two subsections below contain the formulas for the appropriate conversions. The variables are as follows:

• u = vector-U
• v = vector-V
• m = magnitude
• d = direction

#### Magnitude-Direction to U-V

``u = m * cos (pi *d / 180)``

``v = m * sin (pi * d /180)``

#### U-V to Magnitude-Direction

``m = sqrt (u * u + v * v)``

``d = atan2 (v / u) * 180 / p``

## Parameters

ParameterDescription

Raster1

The first input raster.

This will be either the U value or the magnitude.

Raster2

The second input raster.

This will be either the V value or the direction.

Input Data Type

The type of vector field your inputs represent.

• Unknown—It is unknown whether the inputs represent U-V or Magnitude-Direction.
• U-V—Input data represents U and V components.
• Magnitude-Direction—Input data represents magnitude and direction.

Angular Reference System

Specifies how the direction component was measured.

• Geographic—0° points due north, and 90° points due east
• Arithmetic—0° points due east, and 90° points due north

Output Data Type

Specifies the type of vector field your output will represent.

• Magnitude-Direction—Output data represents magnitude and direction.
• U-V—Output data represents U and V components.