The title is quite clear, I'm using Leaflet and I need to show only the vertices of a polyline. For exemple see this image :
Currently I can only have the black line, I'd like only the red squares. Using markers is not an option for performance issue, my lines can be huge (500 000 vertices) and the use of smoothFactor is a need.
Is that possible? If not, does someone knows a plugin that does that, or have a hint on how could I do that by extending the Polyline class?
What you could do here is every time the polyline gets rendered, get the segments of it's SVG path, use those points to add SVG rectangle elements to the polyline's container:
var polyline = L.Polyline([]).addTo(map),
list = polyline._path.pathSegList
// Iterate segments
for (var i = 0; i < list.length; i++) {
// Create SVG rectangle element
rectangle = document.createElementNS('http://www.w3.org/2000/svg', 'rect')
// Set rectangle size attributes
rectangle.setAttributeNS(null, 'height', 4)
rectangle.setAttributeNS(null, 'width', 4)
// Set position attributes, compensate for size
rectangle.setAttributeNS(null, 'x', list[i].x - 2)
rectangle.setAttributeNS(null, 'y', list[i].y - 2)
// Set rectangle color
rectangle.setAttributeNS(null, 'fill', 'red')
// Append rectangle to polyline container
polyline._container.appendChild(rectangle)
}
Seems to work as far as i had time to test it ;) Had to use a timeout though, don't know why, look in to that when i've got more time on my hands.
Example on Plunker: http://embed.plnkr.co/vZI7aC/preview
Related
I'm trying to add circles to my map, but for some reason the circles only show as dots, irrespective of the radius size.
var circle = L.circle(map.unproject([9541, 7658], map.getMaxZoom()), {
radius: 500
}).addTo(map);
I'm using pixel coordinates, but as you can see I'm converting them, so even though I only get dots on the map, they show at the right coordinates. I would hope this isn't the issue, but...?
I've successfully added circleMarkers, but the radius doesn't grow when zooming. At least not that I could see.
So the question is: how can I get the dots to show as circles?
Using Leaflet 1.9.3
Update
It appears that with pixel coordinates you need to enter a really high value for the radius. Thought I had already tried this before asking the question but apparently not.
var circle = L.circle(map.unproject([9541, 7658], map.getMaxZoom()), {
radius: 50000
}).addTo(map);
Unfortunately they're all showing at different sizes, even with the same radius, but that's a different question...
I originally misread your question and gave an incorrect answer, sorry. Circle radius is static. I think that the best way to change it with zoom level would be to use a zoom event listener:
let currZoom = map.getZoom();
let circles = [/* Store your circles here as you create them */];
map.on("zoomend", () => {
const zoomDiff = map.getZoom() - currZoom;
currZoom = map.getZoom();
for (const circle of circles) {
circle.setRadius(circle.getRadius() * 2 ** zoomDiff);
}
});
It's been a while since I've worked with Leaflet, but I think that will do the trick.
Edited to account for your comment regarding multiple circles.
I am working with Leaflet and Leaflet-Draw in Angular to draw some polygons on the Google Map. How can I implement a listener when the user clicks exactly on the edge of the drawn polygons and get the lat and lng of that edge. I know a similar situation can be implemented with Google Map API like the code below, but I can not find any source to help me implement the same thing in Leaflet.
google.maps.event.addListener(polygon, 'click', function (event) { console.log(event.edge) }
Google Map Documentation: https://developers.google.com/maps/documentation/javascript/reference/polygon#PolyMouseEvent
For those who come across this question: I found a solution myself!
I didn't find anything directly from Leaflet draw library that I could use, so I defined the problem for myself as a trigonometry problem and solve it that way.
I defined a function in which on polygon click, it converts the event.latlng and loops over polygon.getLatLngs()[0] taking a pair of A and B points. A is the first coordinates, B is the next and if it reaches to the end of array, B will be the first point. Then using Collinear Function of 3 points with x, y, I checked if the clicked x, y has a same slope as point A and B.(has to be rounded it up), if so, I would save that A and B point pair with their latLng information and further used it in my project.
Although this method works, I would appreciate if anybody would know a better solution or library built-in function that can be used instead. Thanks!
When the user clicks on the polygon you can loop through all corners and check if he clicked in the near of the corner.
poly.on('click', function(e){
var latlng = e.latlng;
var corners = poly.getLatLngs();
if(!L.LineUtil.isFlat(corners)){ //Convert to a flat array
corners = corners[0];
}
//Convert the point to pixels
var point = mymap.latLngToContainerPoint(latlng);
//Loop through each corner
corners.forEach(function(ll){
//Convert the point to pixels
var point1 = mymap.latLngToContainerPoint(ll);
var distance = Math.sqrt(Math.pow(point1.x - point.x, 2) + Math.pow(point.y - point1.y, 2));
//Check if distance between pixels is smaller then 10
if(distance < 10){
console.log('corner clicked');
}
});
});
This is plain JS you have to convert it self to angular.
A alternativ is to place on each corner a DivMarker or a CircleMarker and fire a event if the marker is clicked.
Looks like: https://geoman.io/leaflet-geoman
In Leaflet.Editable I want to confine/limit my customers to draw only in a specific area/bounds.
actually im trying to limit them to (90, -90, 180, -180) bounds of map..
maxBounds: [[-90, -180], [90, 180]]
I was not able to find anything anywhere and it seems that i am missing something.
CODEPEN DEMO
please help.
EDIT:
the Y axis is blocking correctly and mouse cannot stretch shape beyond top and bottom.
the problem is in X axis (as seen in pictures)
as for now i solved it with after save check and clear shape if it out of map bounds (BAD USER EXPERIENCE). i need a mouse confinement just like y axis does.
Without knowing your use case (why the whole world map??) Quickest and easiest fix would be to simply set the map's minZoom to something a bit higher, for example, I found that minZoom: 5 was adequate except for cases where the map was both really short and really wide (which is rarely the case in most apps I've seen).
But the real fix involves writing your own custom overrides for dragging markers and shapes.
According to API doc the L.Editable plugin allows you to override a bunch of stuff including the VertexMarker class, via map.editTools.options.vertexMarkerClass.
Fixed codepen: http://codepen.io/anon/pen/GrPpRY?editors=0010
This snippet of code that allows you to constrain the longitude for dragging vertex markers by correcting values under -180 and over 180 is this:
// create custom vertex marker editor
var vertexMarkerClass = L.Editable.VertexMarker.extend({
onDrag: function(e) {
e.vertex = this;
var iconPos = L.DomUtil.getPosition(this._icon),
latlng = this._map.layerPointToLatLng(iconPos);
// fix out of range vertex
if (latlng.lng < -180) {
e.latlng.lng = latlng.lng = -180;
this.setLatLng(latlng);
}
if (latlng.lng > 180) {
e.latlng.lng = latlng.lng = 180;
this.setLatLng(latlng);
}
this.editor.onVertexMarkerDrag(e);
this.latlng.update(latlng);
this._latlng = this.latlng; // Push back to Leaflet our reference.
this.editor.refresh();
if (this.middleMarker) this.middleMarker.updateLatLng();
var next = this.getNext();
if (next && next.middleMarker) next.middleMarker.updateLatLng();
}
});
// attach custom editor
map.editTools.options.vertexMarkerClass = vertexMarkerClass;
I didn't code for dragging the shape as a whole (the rectangle, in this case). While the VertexMarker fix should address all kinds of vertex dragging, you need to override each shape's drag handler to properly constrain the bounds. And if bounds are exceeded, crop the shape appropriately. As was pointed out, Leaflet already does this for latitude, but because Leaflet allows wrapping the map around horizontally you have your essential problem. Using rec.on("drag") to correct the bounds when they cross over your min/max longitude is the only way to address it. It is basically the same solution as I have laid out for the vertexMarkerClass - actual code left as exercise for the diligent reader.
Does anyone know a way to make overlapping circles in mapbox show the same color and only have the border around the outer edge display?
I have this:
And I made this in photoshop for what I want:
While I don't think there is a way to style all the circles to show their group outline, you can achieve the effect you want by creating a union of all the circle geometries and applying your style to that. Unfortunately, Leaflet's L.circle class offers no way to access a circle's geometry beyond the center point, and to perform a union, you need the path of the circle itself. Fortunately, there is Leaflet Geodesy and its LGeo.circle class, which produces circular polygons with a given radius and number of segments. Once you have these polygon representations of your circles, you can use turf.union to produce the outline you want.
Say you are starting with a layer of points called pointLayer (this can be a L.geoJson, L.mapbox.featureLayer, or any other class that inherits the .eachLayer method). You can then iterate over the features, creating a circular polygon for each of them and adding it to a temporary layer group, like this:
var circleLayer = L.layerGroup();
var radius = 5000
var opts = {
parts: 144
};
pointLayer.eachLayer(function(layer) {
LGeo.circle(layer.getLatLng(), radius, opts).addTo(circleLayer);
});
where radius is in meters and the parts option is the number of segments you want your polygons to have. Next, use the .getLayers method to get an array of all the layers in the temporary group, then iterate over that to create a union of all the features:
var circleUnion = unify(circleLayer.getLayers()).addTo(map);
function unify(polyList) {
for (var i = 0; i < polyList.length; ++i) {
if (i == 0) {
var unionTemp = polyList[i].toGeoJSON();
} else {
unionTemp = turf.union(unionTemp, polyList[i].toGeoJSON());
}
}
return L.geoJson(unionTemp, {style: unionStyle});
}
where unionStyle is whatever style you want to apply to your newly-combined circles. Here is an example fiddle showing all this with some random data:
http://fiddle.jshell.net/nathansnider/L2d626hn/
Specifically I am looking to add text annotations to specific locations to a JFreeChart that is being output to a png file for web use. Can/how do annotations get added to pie charts. I have been able to successfully add annotations to XYPlots, but don't know how to overlay or add one to a PiePlot.
My full task is to use the PiePlot to create a sort of clock. So far everything has worked great, but now I need to add labels at the 12, 3, 6, and 9 o'clock locations and completely stumped.
Adam
Bit of an old question, but here's how I did something similar (annotation at 1, 2, 3, ... o'clock positions) using a polar plot. It uses a ChoiceFormatter and the NumberTickUnit:
final JFreeChart chart = ChartFactory.createPolarChart(
"HAPI Hourly Usage (UTC)", ds, true, true, false);
final PolarPlot plot = (PolarPlot) chart.getPlot();
// Create a ChoiceFormat to map the degrees to clock positions
double[] limits = new double[12];
String[] formats = new String[12];
limits[0] = 0;
formats[0] = "12";
// degrees = 360/12
for (int i = 1; i < limits.length; i++) {
limits[i] = degrees * (i);
formats[i] = Integer.toString(i);
}
ChoiceFormat clock = new ChoiceFormat(limits, formats);
TickUnit tickUnit = new NumberTickUnit(degrees, clock);
// now configure the plot
plot.setAngleTickUnit(tickUnit); // sets the ticks
plot.setAngleLabelsVisible(true); // makes the labels visible
plot.setAngleLabelPaint(Color.LIGHT_GRAY); // user choice
plot.setAngleGridlinesVisible(true); // must set this to display the
// labels
plot.setAngleGridlinePaint(Color.BLACK); // plot's background color
// (makes lines invisible)
plot.setRadiusGridlinesVisible(false); //turn off the radius value circles
ValueAxis axis = plot.getAxis();
axis.setTickLabelsVisible(false); //turn off the radius value labels
winds up looking like http://img522.imageshack.us/img522/6693/hapihours.jpg
After a fairly strenuous search I don't believe this is currently possible (JFreeChart 1.0.13).
Possible options are:
Create a second chart with an XYPlot to generate a second image with needed annotations. Overlay this image on the page. This option is bad because it doubles the number of chart images to be uploaded.
Set the image as a background on the page and HTML the text over the image. Bad because it isn't maintainable and makes a headache of data transfer.
Personally I am just going to find another way to communicate the information in the title, but I wanted to post my findings for the next person.
Adam