Leaflet move single point of polygon in GeoJSON layer - javascript

I have leaflet with a geoJSON layer group and load several geoJSON features, each as a separate layer added to the geoJSON layer group. For a given selected layer, I need to move a point of the polygon on that layer using javascript. So, for example, I may need to move the 3rd vertex to 30.123, -80.123. I cannot figure out how to do this. I can move a marker easily with the setLatLng() method but I can't find anything to change a polygon point.
Here is an example of how I am creating the map and adding my geoJSON features:
function createMap(){
myMap = L.map('locationMap', {
editable: true,
attributionControl: false,
fullscreenControl: true,
fullscreenControlOptions: {
position: 'topleft'
}
}).setView([#Model.MapCenterLat, #Model.MapCenterLong], #Model.MapInitialZoom);
L.tileLayer('#Model.MapUrl2', {
drawControl: true,
maxZoom: 20,
id: 'mapbox.streets'
}).addTo(myMap);
geoJsonLayer = L.geoJson().addTo(myMap);
loadGeoFences('');
}
function loadGeoFences(parentId) {
var url = '#Url.Action("GetGeoFences")';
$.get(url, { parentId: parentId },
function (data) {
if (data.length > 0) {
$.each(data, function (index, value) {
var newLayer = L.geoJson(value,
{
onEachFeature: applyLayerStyle
});
newLayer.addTo(geoJsonLayer);
});
}
});
}

I was able to do this using the leaflet.editing plugin. Once you have the correct layer, the layer.editing.latlngs array can be modified with the desired coordinates. Then call layer.redraw() to update the polygon.

You can change the latlngs while geoJson loading with following:
function onEachFeature(feature, layer) {
if(layer instanceof L.Polyline){
var latlngs = layer.getLatLngs()
var ll = latlngs[0][2];
ll.lat = 51.490056
latlngs[0][2] = ll;
layer.setLatLngs(latlngs);
}
}
L.geoJSON(json,{onEachFeature: onEachFeature}).addTo(map);
https://jsfiddle.net/falkedesign/hvdxo3z7/

Related

Markkers are displayed twice with Leaflet search

I've made a map, based on a geojson file and with clustered markers.
Then I tried to add the leaflet-search plugin.
The search feature works : when I search somtehing, it opens the good popup (informations are generated by "complex" routines).
But now I have my markers displayed twice : the ones I previously created, then those displayed by the search plugin.
How to make leaflet-search to not display its own markers ?
I hope I was clear enough. Bellow here is a sample of my code (I tried to made it readable) :
var geojsonFeature = { mygeojsondata };
// Runs several function to generate an "information page" for each feature
function createPopupInfo(feature, layer) {
var pop = render_name(feature);
//
// ...
}
var nbfeatures = 0;
var layer1 = new L.geoJSON(geojsonFeature, {
onEachFeature: createPopupInfo,
pointToLayer: function (feature, latlng) {
nbfeatures++;
var marker = L.marker(latlng)
arrayOfLatLngs.push(latlng);
marker.on("add", function (event) {
// Retrieve the layer through event.target http://leafletjs.com/reference-1.0.0.html#event-target
event.target.openPopup();
var latLngs = [marker.getLatLng()];
var markerBounds = L.latLngBounds(latLngs);
map.fitBounds(markerBounds);
});
map.maxBoundsViscosity = 0;
return marker;
}
});
var searchControl = new L.Control.Search({
layer: layer1,
propertyName: 'search_index',
marker: false,
moveToLocation: function (latlng, title, map) {
map.setView(latlng, 17);
}
});
searchControl.on('search:locationfound', function (e) {
if (e.layer._popup)
e.layer.openPopup();
}).on('search:collapsed', function (e) {
layer1.eachLayer(function (layer) { //restore feature color
layer1.resetStyle(layer);
});
});
// Clustering
var markers = L.markerClusterGroup();
markers.addLayer(layer1);
map.addLayer(markers);
When the search finds something, harness that event to remove the layer with all the markers:
searchControl.on('search:locationfound', function (e) {
if (e.layer._popup) e.layer.openPopup();
markers.removeLayer(layer1)
})
Of course you'll also want to add these markers back in when you close the search:
searchControlon('search:collapsed', function (e) {
markers.addLayer(layer1);
layer1.eachLayer(function (layer) { //restore feature color
layer1.resetStyle(layer);
});
});
I would say its good UX to also add them all back in when the search comes up empty, but theres' no obvious event for that with leaflet-search.
I found what didn't work, I must pass the "clustered layer" :
var searchControl = new L.Control.Search({
layer: markers,
propertyName: 'search_index',
...
Sources :
https://gis.stackexchange.com/questions/310797/using-l-control-search-and-l-markerclustergroup
https://github.com/stefanocudini/leaflet-search/issues/166
And another example :
http://embed.plnkr.co/46VJcp/

How to add a marker to the middle of a polygon in leaflet?

I want to add a marker in the middle of a polygon that is made form geojson data. The polygon is connected a control where the layer can be turned on and off. This marker should only be displayed when the layer is active. I have the following code:
var geoJsonLayer = L.geoJSON(Locations, {
onEachFeature: function (feature, layer) {
if (feature.geometry.type === "Polygon") {
var bounds = layer.getBounds();
var center = bounds.getCenter();
var markerTitle = feature.properties.ItemId;
layer.id = markerTitle;
var popUpFormat = dataPopUp(feature);
layer.bindPopup(popUpFormat, customPopUpOptions);
}
},
});
Thanks for your interest and I hope someone can help me :D
You want to group a L.Polygon and a L.Marker together, and treat them as the same entity. This is a textbook scenario for using L.LayerGroups, e.g.
var geoJsonLayer = L.geoJSON(Locations, {
onEachFeature: function (feature, layer) {
if (feature.geometry.type === "Polygon") {
var center = layer.getBounds().getCenter();
var marker = L.marker(center);
var polygonAndItsCenter = L.layerGroup([layer, marker]);
}
},
});
Now polygonAndItsCenter is a L.LayerGroup with the polygon and its center (so adding/removing to/from the map will apply to both), but geoJsonLayer will contain only the polygons. How you handle that is up to you, but I guess you might want to not add geoJson to the map (using only for parsing and instantiating the polygons), and keep track of your polygon+marker LayerGroups separately, e.g.
var polygonsWithCenters = L.layerGroup();
var geoJsonLayer = L.geoJSON(Locations, {
onEachFeature: function (feature, layer) {
if (feature.geometry.type === "Polygon") {
var center = layer.getBounds().getCenter();
var marker = L.marker(center);
var polygonAndItsCenter = L.layerGroup([layer, marker]);
polygonAndItsCenter.addTo(polygonsWithCenters);
}
},
});
// geoJsonLayer.addTo(map); // No!!
polygonsWithCenters.addTo(map);
// Do something with a polygon+marker, e.g. remove the first one from the map
polygonsWithCenters.getLayers()[0].remove();
There are a few secondary problems that can spawn for this, so think about what you want to do with each polygon/layergroup/marker before writing code, keep the Leaflet documentation at hand, and remember:
You can not attach events or bind popups to LayerGroups, but you can do that to L.FeatureGroups
The center of a polygon's bounding box is different from its centroid which is different from the point inside the polygon which is furthest away from any of its edges. Only the third option is guaranteed to be inside the polygon.

Best way to convert Leaflet Geojson layers to Leaflet rectangle vector [duplicate]

I am trying to use leaflet's edit function on polygons that I loaded from my database. When I click on leaflet's edit button I get the error
Cannot read property 'enable' of undefined
This thread describes a similar problem, and user ddproxy said
"Since FeatureGroup extends LayerGroup You can walk through the layers
presented and add them individually to the FeatureGroup used for
Leaflet.draw"
I am confused what he means by "walk through", I thought I was adding a layer group, so i'm not sure what I would be walking through. Does this have to do with the fact that i'm adding the polygons as a geoJSON object? Adding the polygons to the map, binding their popups, and assigning them custom colors works perfectly FYI.
The following is the relevant code:
<script>
window.addEventListener("load", function(event){
//other stuff
loadHazards();
});
//next 6 lines siply add map to page
var osmUrl = 'http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png'
var osmAttrib = '© OpenStreetMap contributors'
var osm = L.tileLayer(osmUrl, { maxZoom: 18, attribution: osmAttrib})
var map = new L.Map('map', { center: new L.LatLng(39.255467, -76.711964), zoom: 16 })
osm.addTo(map);
var drawnItems = L.featureGroup().addTo(map);
var Hazards = L.featureGroup().addTo(map);
L.control.layers({
'osm': osm.addTo(map)
},
{
'drawlayer': drawnItems,
"Hazards" : Hazards,
"Tickets": Tickets
},
{
position: 'topleft', collapsed: false
}
).addTo(map);
map.addControl(new L.Control.Draw({
edit: {
featureGroup: Hazards,
poly: {
allowIntersection: false
}
},
draw: {
polygon: {
allowIntersection: false,
showArea: true
},
rectangle:false,
circle:false,
circlemarker:false
}
}));
map.on(L.Draw.Event.CREATED, function (event) {
var layer = event.layer;
drawnItems.addLayer(layer);
});
</script>
And the loadHazards() function:
function loadHazards(){
$.ajax({
type: 'GET',
url:'/loadPolygonFromDatabase',
success : function(polygons){
polygons = JSON.parse(polygons);
var toAdd = [];
for (i in polygons){
var item = {
"type" : "Feature",
"properties":{
"category":"",
"description":"",
"ID":""
},
"geometry" : {
"type":"Polygon",
"coordinates":[],
}
};
item["geometry"]["coordinates"][0] = polygons[i]["coordinates"];
item["properties"]["category"] = polygons[i]["category"];
item["properties"]["description"] = polygons[i]["description"];
item["properties"]["ID"] = polygons[i]["ID"];
toAdd.push(item);
}
//Add information to popup
var layerGroup = L.geoJSON(toAdd, {
onEachFeature: function (feature, layer) {
layer.bindPopup( '<h1>' + feature.properties.category + '</h1>'
+ '<p>' + feature.properties.description + '</p>');
layer.id = feature.properties.ID;
},
style: function(feature){
switch (feature.properties.category) {
case 'Rabid_Beavers': return {color: "#663326"};
case 'Fire': return {color: "#ff0000"};
case 'Flood': return {color: "#0000ff"};
}
}
}).addTo(Hazards);
}
});
}
Thanks in advance!
As mentioned by #ghybs Leaflet.Draw doesn't support Groups or MultiPolygons. I needed the same functionality so a few years ago I created Leaflet-Geoman (previously named leaflet.pm) which supports holes, MultiPolygons, GeoJSON and LayerGroups:
https://github.com/geoman-io/leaflet-geoman
Hope it helps.
Unfortunately Leaflet.draw plugin does not handle nested Layer Groups (same for Feature Groups / GeoJSON Layer Groups).
That is the meaning of the Leaflet.draw #398 issue you reference: they advise looping through the child layers of your Layer/Feature/GeoJSON Layer Group (e.g. with their eachLayer method). If the child layer is a non-group layer, then add it to your editable Feature Group. If it is another nested group, then loop through its own child layers again.
See the code proposed in that post:
https://gis.stackexchange.com/questions/203540/how-to-edit-an-existing-layer-using-leaflet
var geoJsonGroup = L.geoJson(myGeoJSON);
addNonGroupLayers(geoJsonGroup, drawnItems);
// Would benefit from https://github.com/Leaflet/Leaflet/issues/4461
function addNonGroupLayers(sourceLayer, targetGroup) {
if (sourceLayer instanceof L.LayerGroup) {
sourceLayer.eachLayer(function(layer) {
addNonGroupLayers(layer, targetGroup);
});
} else {
targetGroup.addLayer(sourceLayer);
}
}
In your very case, you can also refactor your code with 2 other solutions:
Instead of building your layerGroup (which is actually a Leaflet GeoJSON Layer Group) first and then add it into your Hazards Feature Group, make the latter a GeoJSON Layer Group from the beginning, and addData for each of your single Features (item):
var Hazards = L.geoJSON(null, yourOptions).addTo(map);
for (i in polygons) {
var item = {
"type" : "Feature",
// etc.
};
// toAdd.push(item);
Hazards.addData(item); // Directly add the GeoJSON Feature object
}
Instead of building a GeoJSON Feature Object (item) and parse it into a Leaflet GeoJSON Layer, you can directly build a Leaflet Polygon and add it into your Hazards Layer/Feature Group:
for (i in polygons) {
var coords = polygons[i]["coordinates"];
var style = getStyle(polygons[i]["category"]);
var popup = ""; // fill it as you wish
// Directly build a Leaflet layer instead of an intermediary GeoJSON Feature
var itemLayer = L.polygon(coords, style).bindPopup(popup);
itemLayer.id = polygons[i]["ID"];
itemLayer.addTo(Hazards);
}
function getStyle(category) {
switch (category) {
case 'Rabid_Beavers': return {color: "#663326"};
case 'Fire': return {color: "#ff0000"};
case 'Flood': return {color: "#0000ff"};
}
}

Leaflet Draw "Cannot read property 'enable' of undefined" adding control to geoJSON layer

I am trying to use leaflet's edit function on polygons that I loaded from my database. When I click on leaflet's edit button I get the error
Cannot read property 'enable' of undefined
This thread describes a similar problem, and user ddproxy said
"Since FeatureGroup extends LayerGroup You can walk through the layers
presented and add them individually to the FeatureGroup used for
Leaflet.draw"
I am confused what he means by "walk through", I thought I was adding a layer group, so i'm not sure what I would be walking through. Does this have to do with the fact that i'm adding the polygons as a geoJSON object? Adding the polygons to the map, binding their popups, and assigning them custom colors works perfectly FYI.
The following is the relevant code:
<script>
window.addEventListener("load", function(event){
//other stuff
loadHazards();
});
//next 6 lines siply add map to page
var osmUrl = 'http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png'
var osmAttrib = '© OpenStreetMap contributors'
var osm = L.tileLayer(osmUrl, { maxZoom: 18, attribution: osmAttrib})
var map = new L.Map('map', { center: new L.LatLng(39.255467, -76.711964), zoom: 16 })
osm.addTo(map);
var drawnItems = L.featureGroup().addTo(map);
var Hazards = L.featureGroup().addTo(map);
L.control.layers({
'osm': osm.addTo(map)
},
{
'drawlayer': drawnItems,
"Hazards" : Hazards,
"Tickets": Tickets
},
{
position: 'topleft', collapsed: false
}
).addTo(map);
map.addControl(new L.Control.Draw({
edit: {
featureGroup: Hazards,
poly: {
allowIntersection: false
}
},
draw: {
polygon: {
allowIntersection: false,
showArea: true
},
rectangle:false,
circle:false,
circlemarker:false
}
}));
map.on(L.Draw.Event.CREATED, function (event) {
var layer = event.layer;
drawnItems.addLayer(layer);
});
</script>
And the loadHazards() function:
function loadHazards(){
$.ajax({
type: 'GET',
url:'/loadPolygonFromDatabase',
success : function(polygons){
polygons = JSON.parse(polygons);
var toAdd = [];
for (i in polygons){
var item = {
"type" : "Feature",
"properties":{
"category":"",
"description":"",
"ID":""
},
"geometry" : {
"type":"Polygon",
"coordinates":[],
}
};
item["geometry"]["coordinates"][0] = polygons[i]["coordinates"];
item["properties"]["category"] = polygons[i]["category"];
item["properties"]["description"] = polygons[i]["description"];
item["properties"]["ID"] = polygons[i]["ID"];
toAdd.push(item);
}
//Add information to popup
var layerGroup = L.geoJSON(toAdd, {
onEachFeature: function (feature, layer) {
layer.bindPopup( '<h1>' + feature.properties.category + '</h1>'
+ '<p>' + feature.properties.description + '</p>');
layer.id = feature.properties.ID;
},
style: function(feature){
switch (feature.properties.category) {
case 'Rabid_Beavers': return {color: "#663326"};
case 'Fire': return {color: "#ff0000"};
case 'Flood': return {color: "#0000ff"};
}
}
}).addTo(Hazards);
}
});
}
Thanks in advance!
As mentioned by #ghybs Leaflet.Draw doesn't support Groups or MultiPolygons. I needed the same functionality so a few years ago I created Leaflet-Geoman (previously named leaflet.pm) which supports holes, MultiPolygons, GeoJSON and LayerGroups:
https://github.com/geoman-io/leaflet-geoman
Hope it helps.
Unfortunately Leaflet.draw plugin does not handle nested Layer Groups (same for Feature Groups / GeoJSON Layer Groups).
That is the meaning of the Leaflet.draw #398 issue you reference: they advise looping through the child layers of your Layer/Feature/GeoJSON Layer Group (e.g. with their eachLayer method). If the child layer is a non-group layer, then add it to your editable Feature Group. If it is another nested group, then loop through its own child layers again.
See the code proposed in that post:
https://gis.stackexchange.com/questions/203540/how-to-edit-an-existing-layer-using-leaflet
var geoJsonGroup = L.geoJson(myGeoJSON);
addNonGroupLayers(geoJsonGroup, drawnItems);
// Would benefit from https://github.com/Leaflet/Leaflet/issues/4461
function addNonGroupLayers(sourceLayer, targetGroup) {
if (sourceLayer instanceof L.LayerGroup) {
sourceLayer.eachLayer(function(layer) {
addNonGroupLayers(layer, targetGroup);
});
} else {
targetGroup.addLayer(sourceLayer);
}
}
In your very case, you can also refactor your code with 2 other solutions:
Instead of building your layerGroup (which is actually a Leaflet GeoJSON Layer Group) first and then add it into your Hazards Feature Group, make the latter a GeoJSON Layer Group from the beginning, and addData for each of your single Features (item):
var Hazards = L.geoJSON(null, yourOptions).addTo(map);
for (i in polygons) {
var item = {
"type" : "Feature",
// etc.
};
// toAdd.push(item);
Hazards.addData(item); // Directly add the GeoJSON Feature object
}
Instead of building a GeoJSON Feature Object (item) and parse it into a Leaflet GeoJSON Layer, you can directly build a Leaflet Polygon and add it into your Hazards Layer/Feature Group:
for (i in polygons) {
var coords = polygons[i]["coordinates"];
var style = getStyle(polygons[i]["category"]);
var popup = ""; // fill it as you wish
// Directly build a Leaflet layer instead of an intermediary GeoJSON Feature
var itemLayer = L.polygon(coords, style).bindPopup(popup);
itemLayer.id = polygons[i]["ID"];
itemLayer.addTo(Hazards);
}
function getStyle(category) {
switch (category) {
case 'Rabid_Beavers': return {color: "#663326"};
case 'Fire': return {color: "#ff0000"};
case 'Flood': return {color: "#0000ff"};
}
}

Google Maps - FusionTablesLayer to Polygon

I'm using Google Maps API and jquery-ui-maps (this questions has nothing to do with the plugin which is working great).
I've created a FusionTablesLayer with all countries except Mozambique. The user could place a marker and reposition it. I'm trying to find a way to block the drag (or alert the user, it doesn't matter now) if he tries to place the marker outside Mozambique (over the FusionTablesLayer).
After some research I discover this method: containsLocation(point:LatLng, polygon:Polygon), which computes whether the given point lies inside the specified polygon.
It should receive a Polygon and I've got a FusionTablesLayer. Any clue how to solve this?
Here's my code:FIDDLE
Try to place a marker and drag it...
//Initialize the map
var mapa = $('#map_canvas').gmap({'center': '-18.646245,35.815918'});
$('#map_canvas').gmap('option', 'zoom', 7);
//create the layer (all countries except Mozambique)
var world_geometry;
$('#map_canvas').gmap().bind('init', function(event, map) {
world_geometry = new google.maps.FusionTablesLayer({
query: {
select: 'geometry',
from: '1N2LBk4JHwWpOY4d9fobIn27lfnZ5MDy-NoqqRpk',
where: "ISO_2DIGIT NOT EQUAL TO 'MZ'"
},
styles: [{
polygonOptions: {
fillColor: "#333333",
fillOpacity: 0.3
}
}],
map: map,
suppressInfoWindows: true
});
});
$('#map_canvas').gmap().bind('init', function(event, map) {
$(map).click(function(event) {
$('#map_canvas').gmap('clear', 'markers');
$('#map_canvas').gmap('addMarker', {
'position': event.latLng,
'draggable': true,
'bounds': false
}, function(map, marker) {
}).dragend(function(event) {
//I need to check if the marker is over the FusionTablesLayer and block the drag.
//var test = google.maps.geometry.poly.containsLocation(event.latLng, world_geometry);
}).click(function() {
})
});
});
Since there is no containsLocation in FusionTablesLayer, and since no mouseevents but click is supported (that would have made it a lot easier) - there is no other way round than to check if there is being dragged outside the area itself, Mozambique - not into the FusionTablesLayer. The solution is to create an invisible polygon for Mozambique, and use that polygon to check for containsLocation when dragging is finished.
The polygon can be based on the KML from the row you are excluding, MZ. That can be done using google.visualization.Query.
1) include the Google API loader in your project :
<script type="text/javascript" src="https://www.google.com/jsapi"></script>
2) initialize Visualization :
google.load('visualization', '1.0');
3) define a variable for the polygon holding the Mozambique borders :
var mozambique;
The following is a function that loads the geometry data for Mozambique, and then creates an invisible polygon on the map; google.visualization.Query is used instead of the automated FusionTablesLayer so we can extract the <coordinates> from the KML and use them as base for the polygon.
In basic, this is how to convert KML-data from a FusionTable to a polygon :
function initMozambique(map) {
//init the query string, select mozambique borders
var sql = encodeURIComponent("SELECT 'geometry' FROM 1N2LBk4JHwWpOY4d9fobIn27lfnZ5MDy-NoqqRpk WHERE ISO_2DIGIT ='MZ'");
var query = new google.visualization.Query('http://www.google.com/fusiontables/gvizdata?tq=' + sql);
query.send(function (response) {
var data = response.getDataTable().getValue(0, 0);
//create a XML parser
if (window.DOMParser) {
var parser = new DOMParser();
var kml = parser.parseFromString(data, "text/xml");
} else { // Internet Explorer
var kml = new ActiveXObject("Microsoft.XMLDOM");
kml.loadXML(data);
}
//get the coordinates of Mozambique
var latLngs = kml.getElementsByTagName("coordinates")[0].childNodes[0].nodeValue.split(' ');
//create an array of LatLngs
var mzLatLngs = [];
for (var i = 0; i < latLngs.length; i++) {
var latLng = latLngs[i].split(',');
//<coordinates> for this FusionTable comes in lng,lat format
mzLatLngs.push(new google.maps.LatLng(latLng[1], latLng[0]));
}
//initialize the mozambique polygon
mozambique = new google.maps.Polygon({
paths: mzLatLngs,
fillColor: 'transparent',
strokeColor : 'transparent',
map: map
});
//make the mozambique polygon "transparent" for clicks (pass clicks to map)
google.maps.event.addListener(mozambique, 'click', function(event) {
google.maps.event.trigger(map, 'click', event);
});
});
}
Call the above initMozambique function in your second gmap().bind('init'... :
$('#map_canvas').gmap().bind('init', function(event, map) {
initMozambique(map);
...
Now you can check the mozambique-polygon for containsLocation after dragging
...
}).dragend(function(event) {
if (!google.maps.geometry.poly.containsLocation(event.latLng, mozambique)) {
alert('You are not allowed to drag the marker outside Mozambique');
}
//I need to check if the marker is over the FusionTablesLayer and block the drag.
//var test = google.maps.geometry.poly.containsLocation(event.latLng, world_geometry);
}).click(function() {
})
...
See forked fiddle, working demo with the code above -> http://jsfiddle.net/yb5t6cw6/
Tested in Chrome, FF and IE, ubuntu and windows.

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