Editing of geojson in mapbox gl - mapbox

I am working on a map where I need to load->edit->save geojson.
For now I am trying to use mapbox-gl-draw.js:
Upload geojson from file.
Add it to draw with draw.add()
var feature = {
id: 'unique-id',
type: 'Feature',
properties: {},
geometry: { type: 'Polygon', coordinates: [[[-91.94884436037492,42.807248622513725],[-91.97322027590168,42.7829334446084],[-91.91022055055936,42.7708352918585],[-91.9150270691187,42.79250947320156],[-91.94884436037492,42.807248622513725]]] }
};
var featureIds = draw.add(feature);
Remove the geojson from map
Edit the polygon with draw lib
Transform it back to geojson (put it to the layer) and show it as geojson on the map
Is there an easier way to edit the geojson?
Maybe edit it with draw without removing/updating it from the map
Thanks.

Related

In Mapbox GL JS, can you pass coordinates to an external GeoJSON data source?

Can you pass coordinate values as variables when trying to retreive an external GeoJSON data source? Ideally I'd like to pass something like this, but it doesn't work for me.
map.addSource('geojsonpoints', {
type: "geojson",
data: 'http://myexample.com/pins?lat={lat}&lon={long}'
});
I am able to pass Z, X, Y coordinates if I use Map Vector Tiles (mvt) as a source. i.e. This works:
map.addSource('mapvectortiles', {
'type': 'vector',
'tiles': ['http://myexample.com/{z}/{x}/{y}'],
But I haven't figured out how to do it for a GeoJSON source. Anyone have any ideas if it is possible in n Mapbox GL JS?
FYI, I am able to generate the URL using the method below, but the problem is it doesn't refresh when I move the map, unlike vector tiles.
var lng = map.getCenter().lng
var lat = map.getCenter().lat
var url = 'http://myexample.com/pins?lat='+lat+'&lon='+lng
map.addSource('EPC', {
type: "geojson",
data: url
});
I use GeoJSON to draw Tiles on the map
this is a sample GeoJSON:
{ "type": "FeatureCollection",
"features": [
{ "type": "Feature",
"geometry": {
"type": "Polygon",
"coordinates": [
[
[4.342254780676343, 50.89533552689166],
[4.342254780676343, 50.89443721160754],
[4.340830581474948, 50.89443721160754],
[4.340830581474948, 50.89533552689166],
[4.342254780676343, 50.89533552689166]
]
]
},
"properties": {}
}
]
}
after all you have to add the source and add the layer
add Source:
const sourceJson: GeoJSONSourceRaw = {
type: 'geojson',
data: data as FeatureCollection
};
map.addSource(sourceId, sourceJson)
data is your json file
add Layer:
const layer: FillLayer = {
id: sourceId,
source: sourceId,
type: 'fill',
paint: {
'fill-color': color,
'fill-opacity': opacity
}
}
this.map.addLayer(layer);
There are two parts to your question:
Update the data source when the map is moved
Use the map's extent as part of the GeoJSON source's URL.
You have part 2 under control, so:
Update the data source when the map is moved
Use map.on('moveend', ...
Use map.getSource(...).setData(...)

How I can I get geojson boundary array from existing layer using mapbox gl?

I am using one of the custom tileset of tilling service in mapbox. I loaded that custom tile layer in map using below code.
map.addSource('california', {
type: 'vector',
url: 'mapbox://xyz.california'
});
map.addLayer({
'id': 'terrain-data',
'type': 'fill',
'source': 'california',
'source-layer': 'california',
'layout': {},
'paint': {
'fill-color': 'black',
'fill-opacity': 0.5
}
});
Above code is filling out the inner area with black color. But I want to fill out the outer area of that polygon. Only one way I know to do that is getting difference of whole map with that polygon by using turf.js. After that I will be able to fill the outside area.
Now the question is how can I get the geojson ploygon array of above added layer? So I can calculate the difference.
You can't easily get the complete geometry of a polygon from a vector tile set, because it has already been cut up into tiles. You would have to either find a way to merge them together, or get your geometry into the front end as a complete geojson first.

Mapbox GL JS: zoom to filtered polygon?

I am using Mapbox GL JS to display a polygon layer. I would to allow the user to choose a name from a dropdown, and then highlight and zoom to the matching polygon.
I already know how to highlight the matching polygon using map.setFilter, but I don't know how to zoom to the bounds of the matching polygon. This is my current code:
map.addLayer({
'id': 'polygon_hover',
'source': 'mysource',
'source-layer': 'mylayer',
'type': 'fill',
'paint': {
'fill-color': 'red',
"fill-opacity": 0.6
},
"filter": ["==", 'CUSTNAME', ""]
});
// Get details from dropdown
custname.on("change", function(e) {
// get details of name from select event
map.setFilter('polygon_hover', ["==", 'CUSTNAME', name]);
// Get bounds of filtered polygon somehow?
// var bounds = ??;
// map.fitBounds(bounds);
});
I have examined the Mapbox example of zooming to bounds, but it assumes that you already know what the bounds are.
Is there any way it's possible to get the bounds of the polygon matching a map filter in Mapbox?
I've the following code to fitBounds to Polygon center coords:
var coordinates = f.geometry.coordinates[0];
var bounds = coordinates.reduce(function (bounds, coord) {
return bounds.extend(coord);
}, new mapboxgl.LngLatBounds(coordinates[0], coordinates[0]));
map.fitBounds(bounds, {
padding: 20
});
Where f is one Feature.
I found a solution to your problem. Leaflet has a polygon Class which takes an Array of polygon coordinates and has a function called getBounds() that returns south west and north east bounds. However, Leaflet doesn't follow the convention of LngLat, its format is LatLng. Therefore, you have to switch it. I took an example out from Mapbox Show drawn polygon area, and added exactly what you're looking for.
var polygon = data.features[0].geometry.coordinates;
var fit = new L.Polygon(polygon).getBounds();
var southWest = new mapboxgl.LngLat(fit['_southWest']['lat'], fit['_southWest']['lng']);
var northEast = new mapboxgl.LngLat(fit['_northEast']['lat'], fit['_northEast']['lng']);
var center = new mapboxgl.LngLatBounds(southWest, northEast).getCenter();
// map.flyTo({center: center, zoom: 10});
map.fitBounds(new mapboxgl.LngLatBounds(southWest, northEast));
I see that the question is still relevant - I solved it making a separate request to the database containing all points of a given polygon and building bounds [[minLng, minLat], [maxLng, maxLat]].
All attempts to address geometry of already rendered or source features didn't work for me - most probably because Mapbox doesn't keep initial geoJSON in the tiles.

Using mapbox markers with tiles from OpenStreetMap

Im trying to use the Mapbox API while bringing tiles from OpenStreetMap, but I not finding a way to populate the map with Mapbox markers:
var baseMap, map, notificationMarker, osmAttrib, osmUrl, overlayInfo, streets, systemLocations, systemLocations2, systemsMap;
osmUrl = 'http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png';
osmAttrib = 'Map data © OpenStreetMap';
map = L.mapbox.map('map');
map.setView([39.138, -6.641], 7);
baseMap = L.tileLayer(osmUrl, {
attribution: osmAttrib
}).addTo(map);
L.mapbox.featureLayer({
// this feature is in the GeoJSON format: see geojson.org
// for the full specification
type: 'Feature',
geometry: {
type: 'Point',
// coordinates here are in longitude, latitude order because
// x, y is the standard for GeoJSON and many formats
coordinates: [39.53833, -8.64106]
},
properties: {
title: 'A Single Marker',
description: 'Just one of me',
// one can customize markers by adding simplestyle properties
// http://mapbox.com/developers/simplestyle/
'marker-size': 'large',
'marker-color': '#f0a'
}
}).addTo(map);
Is this feature usage restricted to Mapbox tiles only?
My issue was related to the coordinates array.
The GeoJSON seems to be expecting coordinates with the inverse order.
Where I had:
L.marker([38.13833, -7.24106])
I converted in the geoJSON array to:
coordinates: [-7.24106, 38.13833]
The markers where being displayed on my previous code, simply way ou of the visible area on my map.

Start-Marker from geojson polyline

i have a map with some walking- and bike-routes and popups with a few details an a pic. Now i want to set a marker on the first vertex of a geojson polyline, but i cant find out how. Btw. i´m new to leaflet/mapbox, and i put my map togehter from code snippets.
Here is the map now:
This is how i create the polylines now. I call them via layercontrol.
var mtb = L.geoJson(radjs, {
filter: function (feature, layer) {
if (feature.properties) {
// If the property "underConstruction" exists and is true, return false (don't render features under construction)
return feature.properties.typ === 'mtb';
}
return true;
},
style: {
"color": '#6699cc',
dashArray: '',
"weight": 4,
"opacity": 0.6
}, onEachFeature: onEachFeature2}).addTo(rad);
Thank you for your help,
Marc
You could just add a Feature to your geojson with the latitude and longitude like the do it in the Leaflet GeoJSON Example.
Probably it will be more convenient to read the geometry.coordinates from geojson features and define a new marker.
Beside you have an error on line 569. You should change:
var map = L.mapbox.map('map','',{
to:
var map = L.mapbox.map('map',null,{
Create a simple marker object and add it to the map.
marker = L.marker([0, 0], {
icon: L.mapbox.marker.icon()
}).addTo(map)
Then set the latitude and longitude to the first coordinates of your geoJSON. Assuming your geoJSON is set to the var geojson, you can access the coordinates by indexing into the array.
marker.setLatLng(L.latLng(
geojson.coordinates[0][1],
geojson.coordinates[0][0]))