I'm looking to create an interactive map where a user can simply click to place various polygons/circles of varying size. Once they place these shapes, it would need to be saved so that the next time they visit the page it remembers where the user placed these polygons.
How can I use Mapbox to draw a circle like polygon on a map, of a predefined area/size, with a single click?
There are no circles in mapbox, any shape must be defined as a list of points to form a polygon... so option 1 would be to create your own 'rounded' polygon as a GeoJson feature that you can use as source for a layer... here you have a sample
{"geometry":{"coordinates":[[[-122.12994080132313,47.644482519898276],[-122.12990373140416,47.64449397672769],[-122.12986013420647,47.64449595450196],[-122.12982116483462,47.644490418558235],[-122.1297839964571,47.644476603480825],[-122.12975679969954,47.64445714476511],[-122.12973954095614,47.64443733202884],[-122.12973247670453,47.64440904091012],[-122.12973871662135,47.644379708121534],[-122.1297573021927,47.64435229906627],[-122.12978488013835,47.64433576206736],[-122.12980033418789,47.644325791349985],[-122.12985011085712,47.64431544969429],[-122.12989071574376,47.644316214791644],[-122.12993313243254,47.64432463813935],[-122.12996427964354,47.64434114057201],[-122.12998759690701,47.644364252993626],[-122.13000010533318,47.64438901705185],[-122.1300017490552,47.64441623463529],[-122.12999180010362,47.64444202406153],[-122.12997246871359,47.64446439674887],[-122.12994080132313,47.644482519898276]]],"type":"Polygon"},"type":"Feature","properties":{"name":"circle"}}
You can try using https://studio.mapbox.com/datasets/ to understand how to draw this manually. That would enable to create some predefined 'almost perfect circles' and then allow the users to drag and drop them through the Mapbox-gl-js draw
An option 2 would be to create these shapes is to use turf which is a geospatial js engine which allows you to create some predefined shapes, including circles
But if what you want is to just place the shape of a circle in a concrete point as a marker, that the users can drag and drop, option 3 is in this sample fiddle I have created to show you how to create a custom circle marker, that consist in creating a marker based in an svg circle shape. Obviously this shape doesn't scale as a mapbox polygon vector based.
Just defining a style for the marker (image from wikipedia, you'll need to get your own svg shape)
<style>
.marker {
background-image: url('https://upload.wikimedia.org/wikipedia/commons/a/a0/Circle_-_black_simple.svg');
background-size: cover;
width: 50px;
height: 50px;
border-radius: 50%;
cursor: pointer;
}
</style>
and then the relevant js code
mapboxgl.accessToken = 'PUT YOUR TOKEN HERE';
var geojson = {
'type': 'FeatureCollection',
'features': [{
'type': 'Feature',
'geometry': {
'type': 'Point',
'coordinates': [-77.032, 38.913]
},
'properties': {
'title': 'Mapbox',
'description': 'Washington, D.C.'
}
},
{
'type': 'Feature',
'geometry': {
'type': 'Point',
'coordinates': [-122.414, 37.776]
},
'properties': {
'title': 'Mapbox',
'description': 'San Francisco, California'
}
}
]
};
var map = new mapboxgl.Map({
container: 'map',
style: 'mapbox://styles/mapbox/light-v10',
center: [-96, 15.8],
zoom: 2
});
// add markers to map
geojson.features.forEach(function(marker) {
// create a HTML element for each feature
var el = document.createElement('div');
el.className = 'marker';
// make a marker for each feature and add it to the map
new mapboxgl.Marker(el)
.setLngLat(marker.geometry.coordinates)
.setPopup(
new mapboxgl.Popup({
offset: 25
}) // add popups
.setHTML(
'<h3>' +
marker.properties.title +
'</h3><p>' +
marker.properties.description +
'</p>'
)
)
.addTo(map);
});
EDITED
I forgot an option 4 to have circles on mapbox, in this case to paint circles but it would require some advanced coding to make them draggable. You can create a circles layer in this way...
https://jsfiddle.net/jscastro76/vjkt7wyx/14/
Related
I'm working with Mapbox GL JS to plot geoJSON data on a map using their external geoJSON example as a starting point. The geoJSON file contains lots of features which are plotted as individual markers on the same layer. I would like to highlight the clicked marker by changing its colour from red to blue. I have adapted the example to show a pop-up with the point id when clicked (just as a proof of concept that the markers can fire events when clicked), however, I'm struggling to find a way to change the styling of the individual clicked marker.
The code is currently as follows:
mapboxgl.accessToken = 'pk.eyJ1IjoiZGFuYnJhbWFsbCIsImEiOiJjbDB3ODFveHYxOG5rM2pubWpwZ2R1Y2xuIn0.yatzJHqBTjQ6F3DHASlriw';
const map = new mapboxgl.Map({
container: 'map', // container ID
style: 'mapbox://styles/mapbox/satellite-v9', // style URL
zoom: 7, // starting zoom
center: [138.043, 35.201] // starting center
});
map.on('load', () => {
map.addSource('earthquakes', {
type: 'geojson',
data: 'https://docs.mapbox.com/mapbox-gl-js/assets/earthquakes.geojson'
});
map.addLayer({
'id': 'earthquakes-layer',
'type': 'circle',
'source': 'earthquakes',
'paint': {
'circle-radius': 8,
'circle-stroke-width': 2,
'circle-color': 'red',
'circle-stroke-color': 'white'
}
});
});
map.on('click', 'earthquakes-layer', (e) => {
new mapboxgl.Popup()
.setLngLat(e.lngLat)
.setHTML('Id: ' + e.features[0].properties.id)
.addTo(map);
});
Here is a codepen: https://codepen.io/danb1/pen/BaYjOyx
Is it the case that it's actually not possible to use this approach, and instead each feature from the geoJSON file needs to be plotted as a separate layer? I'm struggling to find any examples of this and am not able to modify the geoJSON source — it has to come from one single file (rather than loading multiple geoJSON files separately on separate layers).
This is possible using feature-state. The first thing to do is to ensure the layer data contains ids for each feature (in the example the source data doesn't so we need to add generateId: true to the map.addSource method).
We then need to add mousemove and mouseleave events to the map to store the moused-over feature id (if there is one, i.e. if the mouse is hovering over a feature):
let hoveredEarthquakeId = null;
map.on('mousemove', 'earthquakes-layer', (e) => {
map.getCanvas().style.cursor = 'pointer';
if (e.features.length > 0) {
map.setFeatureState(
{ source: 'earthquakes', id: e.features[0].id },
{ hover: true }
);
hoveredEarthquakeId = e.features[0].id;
}
});
map.on('mouseleave', 'earthquakes-layer', () => {
map.getCanvas().style.cursor = '';
if (hoveredEarthquakeId !== null) {
map.setFeatureState(
{ source: 'earthquakes', id: hoveredEarthquakeId },
{ hover: false }
);
}
hoveredEarthquakeId = null;
});
Finally, in the layer properties, the colour setting of the circle needs to be updated to reflect the hover value stored against the feature:
'circle-color': [
'case',
['boolean', ['feature-state', 'hover'], false],
'#00f',
'#f00'
],
The final thing can be seen in the modified pen. There is also a MapBox tutorial covering this kind of thing in a slightly more complicated way, which I hadn't come across until now: https://docs.mapbox.com/help/tutorials/create-interactive-hover-effects-with-mapbox-gl-js/.
I have a map with several layers of GeoJSON each with their own unique layer name:
var map = new mapboxgl.Map({
container: 'map',
center: [-97.5651505, 37.89549,],
zoom: 4
});
var sources = {
'ord': 'chicago',
'pit': 'pittsburgh',
'atl': 'atlanta'
};
map.on('load', function () {
for (var s in sources) {
map.addSource(s, { type: 'geojson', data: `/geojson/${s}.json` });
map.addLayer({
'id': sources[s],
'type': 'fill',
'source': s,
'layout': {
'visibility': 'visible'
},
'paint': {
'fill-color': '#088',
'fill-opacity': 0.5
}
});
}
});
I would like to check if a user has zoomed in past zoom level 13 evaluate if any of these three layers is in the viewport. If it is I'll take action to add a button to the overlay. However, I'm having issues finding any documentation other than leaflet on how to check if a layer is inside the viewport. I've found some mention of markers that that doesn't seem to apply.
You can achieve this with queryRenderedFeatures which returns an array of features rendered within a given bounding box. However, if you omit the bounding box argument, queryRenderedFeatures will query within the entire viewport. You can also use the options.layers argument to limit your query to specific layers to avoid getting a bunch of features that are in the underlying style (for example, streets and lakes). You can do this query in a zoomend event listener to achieve your desired outcome. Putting it all together would look something like this:
map.on('zoomend', () => {
if (map.getZoom() > 13) {
const visibleFeatures = map.queryRenderedFeatures(null, {layers: ['ord', 'pit', 'atl']});
// if none of the layers are visible, visibleFeatures will be an empty array
if (visibleFeatures.length) {
// figure out which layers are showing and add your button
}
}
});
I'm using mapbox-gl version 0.46.0-beta.1 (With ReactJS).
I've drawn simple fill layers using GeoJSON source.
The coordinates used to draw the fill are
Coordinates Data:
At a specific zoom level, the polygon renders as expected.
Expected Layer:
But on zooming in, the polygon distorts.
Distorted Fill Layer:
The code I'm using is:
`let paint = {
'fill-color': 'Some Color',
'fill-opacity': 0.4,
'fill-outline-color': 'Some Color'
}
let uniqueID = 'someuniqueID';
map.addLayer({
'id': uniqueID,
'type': 'fill',
'source': {
'type': 'geojson',
'data': {
'type': 'Feature',
'geometry': {
'type': 'Polygon',
'coordinates': [polyCoords]
}
}
},
'paint': paint
})`
We were able to solve the same problem by making sure the first point in the polygon is also the last. For this polygon, you should add the point:
[28.6045067810482..., 77.3860210554725...]
I also had this issue. For a bounding box of coordinates for mapbox, having just the 4 coordinate pairs to create the polygon does create rendering artifacts, directly like above. When making your coordinate bounding box as a polygon, be sure to enter a 5th record, which would be the same as your coordinate at coor[0], where coor is your array of coordinate pairs. You will only notice the weird rendering and re-drawing when zooming, this in fact made it go away for me.
For example:
var coors = [[+sw_lng, +sw_lat], [+sw_lng, +ne_lat], [+ne_lng, +ne_lat], [+ne_lng, +sw_lat]]; //makes a 4 pointed polygon
coors.push(coors[0]); //then continue
I need to create a circle around a point where a user clicks. How would I do this? Every tutorial shows extracting a circle from a geojson source and not creating one. Need to be able to edit the radius as well.
Did you try something yourself? Following the mapbox examples you should be able to get an idea of how to build something like that.
You would need to do 3 things:
Create a source that holds the data
Create a layer of type "circle" for displaying the data as circles
On every click of the user, extract the "latitude, longitude" and add a point to your data list. Then display all of those points as a circle on the map.
This is an example of how I would have coded that: https://jsfiddle.net/andi_lo/495t0dx2/
Hope that helps you out
mapboxgl.accessToken = '####';
var map = new mapboxgl.Map({
container: 'map', // container id
style: 'mapbox://styles/mapbox/light-v9', //stylesheet location
center: [-74.50, 40], // starting position
zoom: 9 // starting zoom
});
map.on('load', () => {
const points = turf.featureCollection([]);
// add data source to hold our data we want to display
map.addSource('circleData', {
type: 'geojson',
data: {
type: 'FeatureCollection',
features: [],
},
});
// add a layer that displays the data
map.addLayer({
id: 'data',
type: 'circle',
source: 'circleData',
paint: {
'circle-color': '#00b7bf',
'circle-radius': 8,
'circle-stroke-width': 1,
'circle-stroke-color': '#333',
},
});
// on user click, extract the latitude / longitude, update our data source and display it on our map
map.on('click', (clickEvent) => {
const lngLat = new Array(clickEvent.lngLat.lng, clickEvent.lngLat.lat);
points.features.push(turf.point(lngLat));
map.getSource('circleData').setData(points);
});
});
#map {
height: 500px;
}
<div id="map"></div>
I'm using Mapbox GL JS, with a Mapbox Streets base layer. I have added a polygon layer with white borders and a transparent fill, but I'm finding it hard to read the basemap labels underneath the polygon layer. See how the labels are covered by the white borders:
Is there any way I can make sure the labels are on top of the polygon layer, or at least not obscured by it?
My code looks like this:
var map = new mapboxgl.Map({
container: 'map',
style: 'mapbox://styles/mapbox/streets-v9',
center: [-2.839, 54.579],
zoom: 4
});
map.on('load', function () {
map.addSource('constituencies', {
'type': 'vector',
'url': 'mapbox://pcsu.xxx'
});
var constituencyLayer = map.addLayer({
'id': 'constituencies',
'source': 'constituencies',
'source-layer': 'constituencies',
'type': 'fill',
'paint': {
'fill-color': 'rgba(162,181,205,0.6)',
'fill-outline-color': 'white'
},
'layout': {
'visibility': 'visible'
}
});
Have a look at this Mapbox example and use the second argument of map.addLayer(layer, [before]). If this layer before exists, the new layer will be placed before/below it. I think the argument naming is a bit confusing here.
The name of the lowest label layer depends on the style. Most of the time you're looking for housenum-label. There's also a discussion in the Mapbox github issues how to ease this process, e.g by introducing placeholder layers.