GeoJSON layer remove/replace data

[tmcw]

The L.geoJson API seems to be missing an API that would make it symmetric:

var layer = L.geoJson();

// we have this
layer.addData(foo);

// we don't have this
layer.removeData(foo);

// or this
layer.getData(foo);
layer.replaceData(foo);

// and if we had this
layer.data(foo); // set the data to foo
layer.data(); // get all data

// we could implement the rest as sugar

[mourner]

Yeah, currently such use cases are handled like this:

layer.clearLayers(); // inherited from LayerGroup
layer.addData(newData);

So GeoJSON class currently acts like a one-way converter of data. But I agree that being able to remove specific objects would be useful.

[tmcw]

This layers-being-layer-groups thing is a bit unclear to me: is there documentation of how it's supposed to work? Basically layers = features?

layer.clearLayers(); // should this be documented in the geojson layer docs, since it does something else here?

[mourner]

GeoJSON layer works exactly like a group, it just adds a couple of GeoJSON-related methods and overrides constructor to accept GeoJSON object. When you call addData, it converts objects to basic Leaflet layers and adds them to itself. When you call clearLayers, it just clears its layers (without any additional GeoJSON-related logic). So it's quite simple.

[paulovieira]

Having the possibility to manipulate GeoJson data in Leaflet core would be a very useful feature. It should be a 2-way process.

I already suggested this some months ago: http://leaflet.uservoice.com/forums/150880-ideas-and-suggestions-for-leaflet/suggestions/3121234-convert-vectors-layers-to-geojson

[emacsen]

I want to say that I too would benefit from this feature. Either being able to remove data, or being able to simply remove all the data from the geoJSON layer.

For a dynamic map where you are replacing the geoJSON data, this functionality would make things better.

[brianherbert]

If I could, +1 on this. I'm currently pulling my hair out trying to manipulate / clear geojson data on the map without hacking around core functionality leaflet.

[JeffPaine]

👍

[MacWeber]

layer.clearLayers();
is not working for clearing the L.geoJson layer.
I cannot figure out how to get rid of old data when I want to update with new GeoJSON data.

[MacWeber]

I realize I was not on HEAD. layer.clearLayers(); is working fine.

[Xeonios]

yep. It's Work on GeoJSON layer for me

[ThomasG77]

+1 to be able to remove one feature at a time and not only clear all.
Playing with a case where I use HTML5 Server Side Events to refresh every 2 sec the data to always keep 10 visible markers (remove the oldest, add the latest). With this example, rerendering everything is quite visible (by doing the clearLayers(); and adding again all features)
Better option maybe?

[andreamartelli]

I fully agree with all of the previous comments.
I used OpenLayers in the past, and in the switch to Leaflet I really enjoyed it's simplicity and mobile friendliness. BUT the lack of this feature is really bad IMHO. It would allow Leaflet to compete with OL also for real-time tracking scenarios and much more.
Developing an extension to the library would be so cool...

[perliedman]

Note that it is possible to remove a single feature from a GeoJSON layer. As @mourner mentions above, L.GeoJSON inherits from L.LayerGroup, which supports removing single layers.

Add an onEachFeature handler for the GeoJSON layer to keep track of the layers associated with a feature (putting them in a map where the feature is the key and the layer is the value, for example), and then use L.LayerGroup's removeLayer to remove them.

A simplistic example of this: http://jsfiddle.net/MLuc3/3/

@mourner any particular reason this issue is still open? Any plans on reworking the API? I'd vore for closing.

[andreamartelli]

Thanks Per. What I'm probably missing is the understanding of the relationship between features and layers in a GeoJSON layer. Is it 1:1? If I add, say, 10 Points, to the layer with addData, do 10 layers get created in the LayerGroup?

[perliedman]

@andreamartelli yes, exactly. For complex geometries, like a GeometryCollection, it will in fact return a FeatureGroup, where each subfeature has its own layer.

You can see how it's done in GeoJSON.js / geometryToLayer.

[tmcw]

@perliedman yep, the core point is that this kind of interface is doable as an abstraction layer, and the current interface is all right. I'll make a note to do it at some point.

[volkanunsal]

layer.clearLayers() is not working for me on version 0.7.3. Is this feature only available on the master branch?

[volkanunsal]

Ah, never mind. Figured out that it is working.

[bgeils]

Here is the code to the solution I implemented. I made a dictionary of all the layers that I could look up and remove whenever necessary.

    var parcelDict = {};

    var queryParcel = Parcel.find();

    queryParcel.observe({
      added: function (item) { 
            parcelDict[item._id._str] = L.geoJson(item, {
                style: {
                    fillColor: "FFF", //overlay color
                    weight: 2,
                    opacity: 1,
                    color: "FFF", // border color
                    fillOpacity: 0.65
                },
                onEachFeature: onEachFeature
            }).addTo(mymap);
        },
      changed: function (newItem) {
          parcelDict[newItem._id._str].clearLayers();
          L.geoJson(newItem, {
                style: {
                    fillColor: "FFF", //overlay color
                    weight: 2,
                    opacity: 1,
                    color: "FFF", // border color
                    fillOpacity: 0.65
                },
                onEachFeature: onEachFeature
            }).addTo(mymap);
        }   
    });

[rowilsonh]

I think leaflet-ajax