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Extremely Poor Performance Using the JavaScript API and a WebMap

Question asked by mhamsa on Nov 22, 2017
Latest reply on Apr 3, 2018 by mhamsa



We have developed a web site that is using the ArcGIS JavaScript 4.3 API and we're noticing some extremely poor performance with the map drawing while using a WebMap loaded with a portal item ID. The map has 1 layer in it with about 900,000 point features. The visibility of the layer is set to Neighborhood so it does not come on until a pretty low zoom level.


It is very common to zoom into a small area of the map on our site and never see the features drawn (the base map is drawn), or to only see a handful of the features when we know there are a lot more in that area. I've even done some tests with the ArcGIS API for JavaScript Sandbox by loading the a WebMap with the same portal item's ID and I see the same issues with performance - I can zoom into an area where I know the features should be drawn and I never see any - never. In contrast, when we log into our ArcGIS Online Portal and open the same web map it seems to draw very quickly. 


So it seems to be a problem with the JavaScript API.


We've tried it on a number of different computers, with different browsers, in different locations on different networks and the same performance issues are seen.


What can we do about this issue? Has anyone else seen this problem? Is there some trick to use to get good performance using the JavaScript API WebMap?


Thanks in advance,