CODEWITHSUNDEEP
openlayers-3
user3637519
user3637519

Reputation: 21

How to force to redraw a layer

I am looking for a method that redraws all the features stored in a layer (equivalent to method "redraw" with OL2)

the method "changed" of class ol.layer.Vector "refreshes" only the features visible on a map (for instance in the zoomed part) and thus doesn't impact the features outside

the treatment applied to those data is to delete periodically old features

how can I achieve this ?

another question is how to be notified of the end of this specific deletion ?

thanks in advance

Jean-Marie

Upvotes: 0

Views: 2714

Answers (2)

user3637519
user3637519

Reputation: 21

first thanks for your answers

my question requires effectively more information :

the browser client receives points through a real time websocket connection

every second, an array of new features collected from those points is added into the Vector layer in this way :

vectorLayer.getSource().addFeatures(features);

the duration of the source buffer is, for instance one hour, and to manage a temporal sliding window of one hour, old features are removed every minute

        map.once('postrender',removeOldFeatures);
        vectorLayer.changed(); or map.renderSync();

this removal is only correctly done for visible features

But as soon as some features are not visible due, for instance, to a zoom on a portion of the map where those features are not displayed, then the removal treatment (removeOldFeatures) is not executed for those features whatever the method used (vectorLayer.changed() or map.render()) as a consequence the number of features doesn't stop increasing...

Jean-Marie

Upvotes: 1

foedchr
foedchr

Reputation: 123

I had the same problem with a TileVector Source and format GeoJSON. At the end i use the provided TileUrlFunction and to redraw the layer, i just set the Source again with the layer.setSource(yourdefinedSource) method. Dube is right. Most of the time (if the source is updated to often) it is useful to send a unique param (like unix timestamp) as a cachebuster.

Upvotes: 0

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