> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ntop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Evaluate Field Gradient

<CardGroup cols={2}>
  <Card title="Scalar Field, Points" href="#scalar-field-points" />

  <Card title="Scalar Field, Point" href="#scalar-field-point" />
</CardGroup>

***

## About this Block

**What it does:** Returns a Vector that represents the rate of change along a Scalar Field at a specific location.

**Common uses:**

* Turning a field into a Vector **Point Map**.

**Tips:**

* To run the block, provide a Field and a Point (or Point List) in which to probe the Field values.
* Turn the evaluated field gradient of Point Lists into a **Point Map** to visualize and analyze the results.
* Similar to using the Field Viewer with the Probe Values option, but the returned value is a property.

## Example File

Download Example: [Evaluate Fields](https://storage.googleapis.com/files-learn/static/ExtendedBlockDocs/evaluate_field.ntop)
![Example Screenshot](https://storage.googleapis.com/files-learn/static/ExtendedBlockDocs/evaluate_field.jpg)

***

<h2 id="scalar-field-points">
  Scalar Field, Points
</h2>

Evaluate the gradient of a scalar field at specific locations.

### Inputs

| Name         | Type                                                               | Description            |
| ------------ | ------------------------------------------------------------------ | ---------------------- |
| Scalar field | [Scalar Field](../../../../block-documentation/types/scalar-field) | Field to evaluate.     |
| Points       | [Point List](../../../../block-documentation/types/point)          | Locations to evaluate. |

### Outputs

| Type                                                        |
| ----------------------------------------------------------- |
| [Vector List](../../../../block-documentation/types/vector) |

***

<h2 id="scalar-field-point">
  Scalar Field, Point
</h2>

Evaluate the gradient of a scalar field at a specific location.

### Inputs

| Name         | Type                                                               | Description           |
| ------------ | ------------------------------------------------------------------ | --------------------- |
| Scalar field | [Scalar Field](../../../../block-documentation/types/scalar-field) | Field to evaluate.    |
| Point        | [Point](../../../../block-documentation/types/point)               | Location to evaluate. |

### Outputs

| Type                                                   |
| ------------------------------------------------------ |
| [Vector](../../../../block-documentation/types/vector) |