topic Re: Reduce the delay requesting attributes of shapefile points in Qt Maps SDK Questions

Reduce the delay requesting attributes of shapefile points

HomeroOriaAguilera — Mon, 02 May 2022 17:27:50 GMT

Hi everyone.

I have this shapefile composed of aprox. 200 000 points with attributes. I read it using a FeatureLayer, with a ServiceFeatureTable in order to stream it from the developer's site layers. I am using a SceneView/Scene context.

I want to select a point to see its attributes, but I must wait that the layer to load all the points, to use the task

identifyLayerWithMaxResults

Ok, that's understandable. But when I change the position of the camera (translation or rotation), the points begin to reload (changes their altitude I guess), and the previous task cannot execute until it finishes.

1. Is this the only way to request the attributes from a FeatureLayer in a dynamic way? We can test FeatureRenderingModeStatic, it solves the problem in some way but it feels laggy sometimes.

2. How can avoid waiting when I change my camera position or rotation?

Re: Reduce the delay requesting attributes of shapefile points

KoushikHajra — Mon, 02 May 2022 18:39:13 GMT

Hello,

Thanks for reaching out to us. Let me make sure that I fully understand your problem. You're trying to idenfityWithMaxResults on the sceneView and then trying to move the camera. The change in the camera position blocks the identify task until it the camera is done moving the new location? Can you please confirm this?

I would expect that the previous task should finish. But I can surely take a look at it and see if I see the same thing.

-Koushik

Re: Reduce the delay requesting attributes of shapefile points

HomeroOriaAguilera — Mon, 02 May 2022 19:12:50 GMT

Yes, indeed. In detail, when I move de camera (or rotate) the points reload again, they maintain their horizontal position and change their elevation though. But this process (the reload), blocks the idenfityWithMaxResults task until it finishes. This can be, 1~3 min. Practically unusable.

When I use FeatureRenderingModeStatic, this delay can be 2~15 seconds. Usable but still slow.

Re: Reduce the delay requesting attributes of shapefile points

KoushikHajra — Tue, 03 May 2022 22:28:39 GMT

Hello,

I looked into this issue and I am not able to reproduce it with other layer types in 3D. So, it leads me to think that this is related to a performance issue we have for shapefiles when using large datasets. It is in our backlog to fix but we're not sure when it will get fixed.

As for any workaround, I am not sure if there is any way you can work around it.

Here is the issue that we have for this problem: https://support.esri.com/en/bugs/nimbus/QlVHLTAwMDEyMTEzOA==

Re: Reduce the delay requesting attributes of shapefile points

HomeroOriaAguilera — Wed, 04 May 2022 02:45:55 GMT

Ok, I understand. Thanks anyway. I think I should bet for a FeatureRenderingModeStatic then.