---
title: "Line dash pattern symbol (polyline helper) | JavaScript maps SDK"
description: "Add dash pattern to line layer using helper."
---
> For AI agents: a documentation index is available at [/llms.txt](https://docs.maptiler.com/llms.txt). Markdown versions of all pages are available by appending .md to any URL.
# Line dash pattern symbol (polyline helper)
In this example, we will explore the process of incorporating a line layer with a dash pattern symbol into the map by utilizing the polyline layer helper. You can access the sample data by downloading the [Amphitheater Lake trail sample data](../../assets/Line_GeoJSON_example.geojson).
By following this approach, we can successfully incorporate a visually appealing dash pattern symbol into our line layer, enhancing its overall appearance and functionality on the map.
### NPM module setup
```bash
npm install --save @maptiler/sdk
```
#### main.js
```js
import { Map, MapStyle, config, helpers } from '@maptiler/sdk';
import '@maptiler/sdk/dist/maptiler-sdk.css';
config.apiKey = 'YOUR_MAPTILER_API_KEY_HERE';
const map = new Map({
container: 'map',
zoom: 14,
center: [-110.75926, 43.72683],
style: MapStyle.OUTDOOR
});
map.on('load', async function () {
await helpers.addPolyline(map, {
data: 'YOUR_MAPTILER_DATASET_ID_HERE',
outline: true,
lineDashArray: "___ _ ",
lineColor: "#F1175D"
});
});
```
#### index.html
```html
Line dash pattern symbol (polyline helper) | NPM example
```
#### style.css
```css
body {margin: 0; padding: 0;}
#map {position: absolute; top: 0; bottom: 0; width: 100%;}
```
### Basic JavaScript setup
```html
Polyline helper
```
## Related examples
### [Line layer (polyline helper)](https://docs.maptiler.com/sdk-js/examples/helper-polyline-minimal/)
Examples
Add minimal line layer using MapTiler polyline helper.
### [Add a KML Line layer (polyline helper)](https://docs.maptiler.com/sdk-js/examples/helper-polyline-kml/)
Examples
Add KML line layer using MapTiler polyline helper.
### [Line outline glow blur symbol (polyline helper)](https://docs.maptiler.com/sdk-js/examples/helper-polyline-blur/)
Examples
Add glowing outline to line layer using helper.
### [GeoJSON line layer](https://docs.maptiler.com/sdk-js/examples/geojson-line/)
Tutorials
Add a GeoJSON line overlay to the map application.