GeoGrid for MapLibre GL

GeoGrid is a MapLibre GL JS plugin for adding a highly customizable geographic grid (graticule) to your map.

Features

• Display Geographic Grid: Adds a grid with labeled coordinates to the map.
• Customizable Grid Density: Adjust grid density dynamically based on zoom level.
• Zoom Level Visibility Range: Control grid visibility with the zoomLevelRange option.
• Custom Label Formats: Change the label format to suit your needs. Default format:
  [degrees]° [minutes]’ [seconds]’’
• CSS Label Styling: Easily style labels using CSS (e.g., text shadows, blending modes).
• Flexible Grid Styling: Modify grid line color and width via the API.
• Layer Placement Control: Place grid lines under any existing map layer using beforeLayerId.
• Dynamic Label Visibility: Labels automatically hide when the map is rotated away from north.
• Optimized Performance: Only elements visible in the viewport are rendered, ensuring no performance impact.
• Easy Removal: Remove the grid programmatically using the remove() method.
• TypeScript Support: Includes TypeScript definitions for better development experience.
• ES Module Ready: Available as a JavaScript module for modern workflows.

Installation

Get it from NPM:

npm i geogrid-maplibre-gl

Or use it from the CDN:

<script type="module" src="https://unpkg.com/geogrid-maplibre-gl@latest"></script>
<link href="https://unpkg.com/geogrid-maplibre-gl@latest/dist/geogrid.css" rel="stylesheet" />

Usage

Minimal example

import { GeoGrid } from 'geogrid-maplibre-gl';
// Import css from 'geogrid-maplibre-gl/dist/geogrid.css'

// const map = new maplibregl.Map(...);

new GeoGrid({ map });

All options

import { GeoGrid } from 'geogrid-maplibre-gl';

// const map = new maplibregl.Map(...);

new GeoGrid({ 
    map,
    beforeLayerId: 'labels'
    style: {
        color: 'rgba(255, 255, 255, 0.5)'
        width: 2
    },
    zoomLevelRange: [0, 13],
    gridDensity: (zoomLevel) => 10;
    formatLabels: (degreesFloat) => Math.floor(degreesFloat);
});

Programatically removing and re-adding:

const geogrid = new GeoGrid({ map });

// On some event
geogrid.remove();

// On another event
geogrid.add();

Styling

Customize the appearance of the grid labels by overriding the following CSS classes:

• geogrid - The main container for labels.
• geogrid__label - Invidual label elements.
• geogrid__label--left - Labels on the left.
• geogrid__label--right - Labels on the right.
• geogrid__label--top - Labels on the top.
• geogrid__label--bottom - Labels on the bottom.

To prevent overriding default properties, nest overrides inside .geogrid-overrides selector.

For example:

.geogrid-overrides .geogrid__label {
    color: red
}