Leaflet – Count Features by Type in a FeatureGroup Using JavaScript

javascriptleaflet

Is there any way in leaflet to get the number of rectangles in a feature group?
I know this code that work: drawnItems.getLayers().length; but it counts all the objects within the drawnItems featuregroup. I only need the a specific type of features, for example rectangle

Best Answer

Assuming that you are using instances of L.Rectangle, you can use functional programming like so:

drawnItems.getLayers().filter( function(l) {return l instanceof L.Rectangle} ).length;

The filter method of Array will return another array, containing only the elements which make the callback function return true; in this case, it will return an array containing only those layers which are instances of L.Rectangle.

Related Solutions

[GIS] Leaflet geoJson in front of markers in a FeatureGroup

The only thing I suggest is using something other than markers for the layer that is to go on the bottom.

Try using a circle or point layer instead of a marker layer. That should work.

I reckon markers are designed to always be on top.

[GIS] leaflet remove a specific type of features from featuregroup

In a similar way to my answer to leaflet count by featuretypes in featuregroup :

drawnItems
  .filter(function(layer) {
    return layer instanceof L.Marker;
  })
  .forEach(function(layer) {
    map.removeLayer(layer);
  });

Or in a shorter one-liner using arrow functions:

drawnItems.getLayers().filter(l=>l instanceof L.Marker).forEach(l=>map.remove(l));

Remember to check the documentation for Array.prototype.filter and Array.prototype.forEach.

On the other hand, you should consider creating several L.FeatureGroups, one for each kind of layer you want to add/remove from/to the map.

Best Answer

Related Solutions

[GIS] Leaflet geoJson in front of markers in a FeatureGroup

[GIS] leaflet remove a specific type of features from featuregroup

Related Question