> For the complete documentation index, see [llms.txt](https://docs.carto.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.carto.com/data-and-analysis/analytics-toolbox-for-bigquery/sql-reference/accessors.md).

# accessors

This module contains functions that provide information about internal geometries.

## ST\_ENVELOPE <a href="#st_envelope" id="st_envelope"></a>

```sql
ST_ENVELOPE(geog)
```

**Description**

Takes any number of features and returns a rectangular Polygon that encompasses all vertices.

**Input parameters**

* `geog`: `ARRAY<GEOGRAPHY>` input features.

**Return type**

`GEOGRAPHY`

**Example**

{% tabs %}
{% tab title="carto-un" %}

```sql
SELECT `carto-un`.carto.ST_ENVELOPE([ST_GEOGPOINT(-75.833, 39.284), ST_GEOGPOINT(-75.6, 39.984), ST_GEOGPOINT(-75.221, 39.125)]);
-- POLYGON((-75.833 39.125, -75.68 39.125 ...
```

{% endtab %}

{% tab title="carto-un-eu" %}

```sql
SELECT `carto-un-eu`.carto.ST_ENVELOPE([ST_GEOGPOINT(-75.833, 39.284), ST_GEOGPOINT(-75.6, 39.984), ST_GEOGPOINT(-75.221, 39.125)]);
-- POLYGON((-75.833 39.125, -75.68 39.125 ...
```

{% endtab %}

{% tab title="manual" %}

```sql
SELECT carto.ST_ENVELOPE([ST_GEOGPOINT(-75.833, 39.284), ST_GEOGPOINT(-75.6, 39.984), ST_GEOGPOINT(-75.221, 39.125)]);
-- POLYGON((-75.833 39.125, -75.68 39.125 ...
```

{% endtab %}
{% endtabs %}

<img src="https://3029946802-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FybPdpmLltPkzGFvz7m8A%2Fuploads%2Fgit-blob-1c82685e4e434438152a8e3d867df996413489fe%2Feu-flag-website.png?alt=media&amp;token=4343f6e5-973a-4e9a-8e14-50366a086f72" alt="EU flag" data-size="line">This project has received funding from the [European Union’s Horizon 2020](https://ec.europa.eu/programmes/horizon2020/en) research and innovation programme under grant agreement No 960401.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.carto.com/data-and-analysis/analytics-toolbox-for-bigquery/sql-reference/accessors.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.