---
title: lttb() | Tiger Data Docs
description: Downsample a time series using the Largest Triangle Three Buckets method
---

Since [1.10.1](https://github.com/timescale/timescaledb-toolkit/releases/tag/1.10.1)

Downsample your data with the [Largest Triangle Three Buckets algorithm](https://github.com/sveinn-steinarsson/flot-downsample). This algorithm tries to retain visual similarity between the downsampled data and the original dataset.

## Samples

This example uses a table with raw data generated as a sine wave. You can use LTTB to dramatically reduce the number of points while still capturing the peaks and valleys in the data.

```
SET TIME ZONE 'UTC';
CREATE TABLE metrics(date TIMESTAMPTZ, reading DOUBLE PRECISION);
INSERT INTO metrics
SELECT
    '2020-1-1 UTC'::timestamptz + make_interval(hours=>foo),
    (5 + 5 * sin(foo / 24.0 * PI()))
    FROM generate_series(1,168) foo;


SELECT time, value
FROM unnest((
    SELECT lttb(date, reading, 8)
    FROM metrics))
```

```
time                    |               value
------------------------+---------------------
2020-01-01 01:00:00+00  |   5.652630961100257
2020-01-01 13:00:00+00  |   9.957224306869053
2020-01-02 11:00:00+00  | 0.04277569313094798
2020-01-03 11:00:00+00  |   9.957224306869051
2020-01-04 13:00:00+00  | 0.04277569313094709
2020-01-05 16:00:00+00  |   9.330127018922191
2020-01-06 20:00:00+00  |  2.4999999999999996
2020-01-08 00:00:00+00  |   5.000000000000004
```

## Arguments

The syntax is:

```
lttb(
  ts TIMESTAMPTZ,
  value DOUBLE PRECISION,
  resolution INT
) RETURNS Timevector
```

| Name       | Type             | Default | Required | Description                                                                                              |
| ---------- | ---------------- | ------- | -------- | -------------------------------------------------------------------------------------------------------- |
| ts         | TIMESTAMPTZ      | -       | ✔        | Timestamps for each data point                                                                           |
| value      | DOUBLE PRECISION | -       | ✔        | The value at each timestamp                                                                              |
| resolution | INT              | -       | ✔        | The approximate number of points to return. Determines the horizontal resolution of the resulting graph. |

## Returns

| Column | Type       | Description                                                                                                                                                                                                                             |
| ------ | ---------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| lttb   | Timevector | An object representing a series of values occurring at set intervals from a starting time. It can be unpacked with `unnest`. For more information, see the documentation on [timevectors](/docs/reference/toolkit/timevector/index.md). |