Show polygon information on click
In this example, when a user clicks a polygon in a specified layer, the map shows a popup containing information about the clicked feature.
When the map loads, it uses addSource
and addLayer
to add and style a layer called states-layer
, which contains state polygons.
When the user clicks a feature in the states-layer
layer, the example uses the Popup
method to create a new popup, using MapMouseEvent
data to set the position and content of the popup.
Lastly, it uses the Map
events mouseenter
and mouseleave
to toggle the user's cursor to a pointer while it hovers over any feature in states-layer
.
<!DOCTYPE html><html><head><meta charset="utf-8" /><title>Show polygon information on click</title><meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" /><script src="https://cdn.ndrive.com/nmapsgl/v.1.6.8/nmaps-gl.js"></script><link href="https://cdn.ndrive.com/nmapsgl/v.1.6.8/nmaps-gl.css" rel="stylesheet" /><style> body { margin: 0; padding: 0; } #map { position: absolute; top: 0; bottom: 0; width: 100%; }</style></head><body><style>.nmapsgl-popup {max-width: 400px;font: 12px/20px 'Helvetica Neue', Arial, Helvetica, sans-serif;}</style><div id="map"></div><script> // TO MAKE THE MAP APPEAR YOU MUST ADD YOUR ACCESS TOKEN nmapsgl.accessToken = '<your access token here>'; const map = new nmapsgl.Map({container: 'map',style: 'Streets',center: [-100.04, 38.907],zoom: 3}); map.on('load', () => {// Add a source for the state polygons.map.addSource('states', {'type': 'geojson','data': 'https://d2ad6b4ur7yvpq.cloudfront.net/naturalearth-3.3.0/ne_110m_admin_1_states_provinces_shp.geojson'}); // Add a layer showing the state polygons.map.addLayer({'id': 'states-layer','type': 'fill','source': 'states','paint': {'fill-color': 'rgba(200, 100, 240, 0.4)','fill-outline-color': 'rgba(200, 100, 240, 1)'}}); // When a click event occurs on a feature in the states layer, open a popup at the// location of the click, with description HTML from its properties.map.on('click', 'states-layer', (e) => {new nmapsgl.Popup().setLngLat(e.lngLat).setHTML(e.features[0].properties.name).addTo(map);}); // Change the cursor to a pointer when the mouse is over the states layer.map.on('mouseenter', 'states-layer', () => {map.getCanvas().style.cursor = 'pointer';}); // Change it back to a pointer when it leaves.map.on('mouseleave', 'states-layer', () => {map.getCanvas().style.cursor = '';});});</script> </body></html>