I am able to find and change the properties of a vector tileset using expression, for example:
map.setPaintProperty('my-shp', 'fill-opacity', [
'match',
['get', 'NO'],
13708, 1,
/* else */ 0
]);
I was wondering if there is a way to get the exact coordinate of the tileset item using expression?
Sorry if I am wrong with the terminology (of tileset/tile item), feel free to correct me. Thanks
To clarify, using the above expression, I can change the opacity of the tileset item where NO is 13708. My question is, is there a way to get the lat/long coordinate of the tileset item where NO is 13708?
You could just iterate over all rendered features and test the "NO" property then return the coordinates of this feature. To get all rendered features you need to use queryRenderedFeatures. Features follow the GeoJSON structure.
For example:
let features = map.queryRenderedFeatures({ layers: ['my-shp'] });
let filtered = features.filter(feature => {
return feature.properties.NO === 13708;
});
console.log(filtered);
Related
I have displayed the the result markers for the leaflet-knn on the map with following code:
const myloc = new L.LatLng(13.7433242, 100.5421583);
var gjLayer = L.geoJson(testCities, {
onEachFeature: function(feature, layer) {
content = "<b>Name:</b> " + feature.properties.name;
layer.bindPopup(content);
}
});
var longitude = myloc.lng,
latitude = myloc.lat;
var res = leafletKnn(gjLayer).nearest(
[longitude, latitude], 5, distance);
for (i = 0; i < res.length; i++) {
map.addLayer(res[i].layer);
}
Now I want to change the color of this marker that is added or I want to change the icon.
Can anybody tell me how can I do?
Leaflet-knn is agnostic when it comes to the representation of the results - it relies on the existing L.Layers: it takes a L.GeoJSON as an input and then iterates through all its members in order to fetch all their coordinates (in the case of polylines and polygons) and then store a reference to the L.Layer for each of its coordinates.
The results of a leaflet-knn search include the original L.Layer from the L.GeoJSON that was passed at instantiation time.
Either symbolize your GeoJSON afterwards, as explained in the Leaflet tutorials, or create new markers/symbols for the results after each query.
Right now your code is relying on the default symbolization of GeoJSON data (instantiate a L.Marker with a L.Icon.Default for points). I suggest the approach of displaying your L.GeoJSON in the map to ensure that it looks like you want it to (even if it's a partial set of the data), then implementing the leaflet-knn search.
I am trying to update an old Mapbox.js map to Mapbox GL. I am generating the map from geojson (and using coffescript).
map.addSource 'my_datasource',
'type': 'geojson'
'data': my_geojson
map.addLayer
'id': 'my_layer'
'type': 'symbol'
'source': 'my_datasource'
I am filtering the layer based on a user input that returns value
map.setFilter('my_layer', ["==", 'my_attribute', value ])
So far, so good. But now I want to zoom and reposition the map to fit the bounds of the filtered symbols.
I thought I would be able to do something like this
bounds = new (mapboxgl.LngLatBounds)
map.queryRenderedFeatures(layers: [ 'my_layer' ]).forEach (feature) ->
bounds.extend feature.geometry.coordinates
return
map.fitBounds bounds
But queryRenderedFeatures appears to be returning all (i.e., un-filtered) symbols.
After much reading around, my understanding is that queryRenderedFeatures should return the filtered symbols that are visible in the viewport (i.e., would be suitable for zooming in but not zooming out).
Is this correct? And if so, why is my function above returning unfiltered symbols? Appreciate any advice to help my transition to MapboxGL!
It's a bit unclear to me from the documentation whether filters in the layer should be applied, but in any case, there is an explicit filter parameter you can, pass, so:
map.queryRenderedFeatures(layers: [ 'my_layer' ], filter:["==", 'my_attribute', value ]).forEach (feature) ->
bounds.extend feature.geometry.coordinates
But I suspect you really want querySourceFeatures, because you don't want to be constrained by what's currently within the viewport:
map.querySourceFeatures(my_source, filter:["==", 'my_attribute', value ]).forEach (feature) ->
bounds.extend feature.geometry.coordinates
or, in native ES2015:
map.querySourceFeatures(my_source, { filter:['==', 'my_attribute', value ]} )
.forEach (feature => bounds.extend(feature.geometry.coordinates))
Try this post, I have added the code which will let you have the features using queryRenderedFeatures() or even using querySourceFeatures():
https://stackoverflow.com/a/66308173/9185662
I am exporting Google Directions routes as KML and displaying them on a Mapbox map by reading them with Omnivore and adding them to the map,
The Google KML stores each route as two Places (the start and end points) and one LineString (the route). In Mapbox I would like to show only the routes, that is to filter out the markers somehow. I'm displaying markers out of my own database and the Google markers clutter it up.
Here is my code. I change the styling of the LineStrings just to show that I can, but do not know what magic call(s) to make to not display the Points.
Thanks.
runLayer = omnivore.kml('data/xxxx.kml')
.on('ready', function() {
var llBnds = runLayer.getBounds();
map.fitBounds(llBnds);
this.eachLayer(function (layer) {
if (layer.feature.geometry.type == 'LineString') {
layer.setStyle({
color: '#4E3508',
weight: 4
});
}
if (layer.feature.geometry.type == 'Point') {
//
// Do something useful here to not display these items!!
//
}
});
})
.addTo(map);
Welcome to SO!
Many possible solutions:
Most straight forward from the code you provided, just use the removeLayer method on your runLayer Layer Group when you get a 'Point' feature.
Cleaner solution would be to filter out those features before they are even converted into Leaflet layers, through a custom GeoJSON Layer Group passed as 3rd argument of omnivore.kml, with a specified filter option:
var customLayer = L.geoJSON(null, {
filter: function(geoJsonFeature) {
// my custom filter function: do not display Point type features.
return geoJsonFeature.geometry.type !== 'Point';
}
}).addTo(map);
var runLayer = omnivore.kml('data/xxxx.kml', null, customLayer);
You can also use the style and/or onEachFeature options on customLayer to directly apply your desired style on your LineString.
I would like to have certain layers to be always on top of others, no matter in which order they are added to the map.
I am aware of bringToFront(), but it does not meet my requirements. I would like to set the zIndex dynamically based on properties.
Leaflet has the method setZIndex(), but this apparently does not work for geoJson layers:
https://jsfiddle.net/jw2srhwn/
Any ideas?
Cannot be done for vector geometries.
zIndex is a property of HTMLElements, and vector geometries (lines and polygons) are rendered as SVG elements, or programatically as <canvas> draw calls. Those two methods have no concept of zIndex, so the only thing that works is pushing elements to the top (or bottom) of the SVG group or <canvas> draw sequence.
Also, remind that L.GeoJSON is just a specific type of L.LayerGroup, in your case containing instances of L.Polygon. Furthermore, if you read Leaflet's documentation about the setZIndex() method on L.LayerGroup:
Calls setZIndex on every layer contained in this group, passing the z-index.
So, do L.Polygons have a setZIndex() method? No. So calling that in their containing group does nothing. It will have an effect on any L.GridLayers contained in that group, though.
Coming back to your problem:
I would like to have certain layers to be always on top of others, no matter in which order they are added to the map.
Looks like the thing you're looking for is map panes. Do read the map panes tutorial.
This is one of the reason for the implementation of user defined "panes" in Leaflet 1.0 (compared to versions 0.x).
Create panes: var myPane = map.createPane("myPaneName")
If necessary, set the class / z-index of the pane element: myPane.style.zIndex = 450 (refer to z-index values of built-in panes)
When creating your layers, specify their target pane option: L.rectangle(corners, { pane: "myPaneName" })
When building through the L.geoJSON factory, you can loop through your features with the onEachFeature option to clone your layers with specified target pane.
Demo: https://jsfiddle.net/3v7hd2vx/90/
For peoples who are searching about Z-Index
All path layers (so all except for markers) have no z-index because svg layers have a fix order. The first element is painted first. So the last element is painted on top.
#IvanSanchez described good why zIndex not working.
You can control the order with layer.bringToBack() or layer.bringToFront().
With that code you have more options to control the order of the layers.
L.Path.include({
getZIndex: function() {
var node = this._path;
var index = 0;
while ( (node = node.previousElementSibling) ) {
index++;
}
return index;
},
setZIndex: function(idx) {
var obj1 = this._path;
var parent = obj1.parentNode;
if(parent.childNodes.length < idx){
idx = parent.childNodes.length-1;
}
var obj2 = parent.childNodes[idx];
if(obj2 === undefined || obj2 === null){
return;
}
var next2 = obj2.nextSibling;
if (next2 === obj1) {
parent.insertBefore(obj1, obj2);
} else {
parent.insertBefore(obj2, obj1);
if (next2) {
parent.insertBefore(obj1, next2);
} else {
parent.appendChild(obj1);
}
}
},
oneUp: function(){
this.setZIndex(this.getZIndex()+1)
},
oneDown: function(){
this.setZIndex(this.getZIndex()-1)
}
});
Then you can call
polygon.oneUp()
polygon.oneDown()
polygon.setZIndex(2)
polygon.getZIndex()
And now layergroup.setZIndex(2) are working
I'm trying to make a mapping visualization in realtime, where I keep getting new points via websockets. The initial plotting these markers on the map seems simple, but I'm not sure what's the right way of updating a layer on Mapbox.
As of now, whenever I get a new point, I remove the old layer, create a new one and then add it on the map. The problem with this approach is that it is slow and for high number of points (>5000) it starts lagging.
// remove layer
if (this.pointsLayer != null) {
map.removeLayer(this.pointsLayer);
}
// build geoJSON
var geoJSON = { "type": "FeatureCollection", "features": [] };
geoJSON["features"] = tweets.map(function(tweet) {
return this.getGeoPoint(tweet);
}.bind(this));
// add geoJSON to layer
this.pointsLayer = L.mapbox.featureLayer(geoJSON, {
pointToLayer: function(feature, latlon) {
return L.circleMarker(latlon, {
fillColor: '#AA5042',
fillOpacity: 0.7,
radius: 3,
stroke: false
});
}
}).addTo(map);
Is there a better way?
You can create an empty GeoJSON layer by passing it a false instead of real data:
//create empty layer
this.pointsLayer = L.mapbox.featureLayer(false, {
pointToLayer: function(feature, latlon) {
return L.circleMarker(latlon, {
fillColor: '#AA5042',
fillOpacity: 0.7,
radius: 3,
stroke: false
});
}
}).addTo(map);
then use .addData to update it as new tweets come in. Something like:
// build geoJSON
var geoJSON = { "type": "FeatureCollection", "features": [] };
geoJSON["features"] = /**whatever function you use to build a single tweet's geoJSON**/
// add geoJSON to layer
this.pointsLayer.addData(geoJSON);
For a single tweet, I guess you could just create a Feature instead of a FeatureCollection, though I don't know whether that extra layer of abstraction would make any difference in terms of performance.
EDIT: Here is an example fiddle showing the .addData method at work:
http://jsfiddle.net/nathansnider/4mwrwo0t/
It does slow down noticeably if you add 10,000 points, and for 15,000 points, it's really sluggish, but I suspect that has less to do with how the points are added that the demands of rendering so many circleMarkers.
If you aren't already, you may want to try using the new Leaflet 1.0 beta, which redraws vector layers faster and is generally much more responsive with large datasets. Compare this 15,000-point example using Leaflet 0.7.5 to the same code using Leaflet 1.0.0b2. Not everything is fixed (popups take a long time to open in both), but the difference in lag time when trying to drag the map is pretty dramatic.
There's no reason to go through the intermediate step of construction a GeoJSON object just so you can add it to the map. Depending on your exact needs, you can do something like this:
tweets.forEach(function(t) {
L.marker(this.getGeoPoint(t)).addTo(map);
}, this);
You should manage the tweets object so it only contains points that are not already visible on the map, though. Deleting all the old markers, just so you can add them again, is of course going to be very slow.
I would take a look at Leaflet Realtime:
Put realtime data on a Leaflet map: live tracking GPS units, sensor data or just about anything.
https://github.com/perliedman/leaflet-realtime