topic Re: Efficiently Move Polylines in .NET Maps SDK Questions

Efficiently Move Polylines

ScottBrady1 — Sun, 10 Jun 2018 22:32:21 GMT

Hi,

I am aware that the MapPoint object has the MoveTo function that allows one to efficiently move points from one location to another without re-creating the object.

Is there a method or technique that facilitates moving polylines between two locations on each timer tick without incurring the overhead of creating new Polyline objects.

Kind Regards

Scott

Re: Efficiently Move Polylines

ScottBrady1 — Mon, 11 Jun 2018 06:50:14 GMT

Forgot to mention that its for 10.2.7

Re: Efficiently Move Polylines

dotMorten_esri — Mon, 11 Jun 2018 15:31:49 GMT

The move operation is a very special-case optimization at the GPU level and only works for points. It gets complicated really quickly for lines and polygons and a similar optimization isn't really possible. There's not really a way around generating a new line or polygon for these scenarios

Re: Efficiently Move Polylines

ScottBrady1 — Tue, 12 Jun 2018 00:03:24 GMT

This is unfortunate news as we are reviewing your product in the hopes that in can sustain a large number of mappoints with interconnecting relationships between other points using polylines. Creating and destroying thousands of polylines per second is an expensive operation in terms of application performance and responsiveness.

Re: Efficiently Move Polylines

dotMorten_esri — Tue, 12 Jun 2018 22:44:23 GMT

I just modified my flight-tracker sample to also animate lines. It's handling around 8000 points, with about 2-300 updates/second. Animating the points at 60 frames per second + animating a line to each of those points didn't seem like an issue at all.

I'm curious to know what sort of problems you were hitting with this?

Re: Efficiently Move Polylines

ScottBrady2 — Mon, 25 Jun 2018 00:47:09 GMT

Is it possible that i could have access to this modified flight tracker sample?

Kind Regards

Scott

Re: Efficiently Move Polylines

ScottBrady2 — Wed, 27 Jun 2018 04:25:34 GMT

Hi,

Anyone there.

Kind Regards

Scott Brady

Re: Efficiently Move Polylines

dotMorten_esri — Wed, 27 Jun 2018 05:13:17 GMT

I based it off of this sample: arcgis-runtime-demos-dotnet/src/GeoEventServerSample at master · Esri/arcgis-runtime-demos-dotnet · GitHub

However I'm using a different must more intense service that I can't share, and I extended with some line animations. I doubt the example is useful for your scenario - I merely hacked some stuff in quickly just to get a feel for the performance, and it seemed ok.

Re: Efficiently Move Polylines

ScottBrady2 — Wed, 27 Jun 2018 06:01:44 GMT

Hi Morten,

My application is significantly more complex than the demo you provide.

MapPoints are not an issue.

I can add as many points on the map as I like and everything is efficient.

My problem comes when I add maplines to the map.

Each point has a line connecting up to nineteen other points.

Consequently I can have thousands of map objects on the map at any given time updated every second using a timer.

It is only when adding the lines to the map that performance begins to degrade.

Points are handled efficiently as I simply can call the moveto function and not have to recreate them.

The lines on the other hand have to be cleared from the map and recreated on each timer tick.

I have reviewed many products on the market and with this like what I see.

This issue however is integral to our product.

Our requirements are quite demanding and intensive.

Kind Regards

Scott Brady

Re: Efficiently Move Polylines

dotMorten_esri — Fri, 29 Jun 2018 18:15:22 GMT

> The lines on the other hand have to be cleared from the map and recreated on each timer tick.

You don't need to clear them out. You'll just update the geometry property on each graphic.

I had around 200--300 lines updating continuously 60 times per second, and over 8000 lines rendering total (not everything updates every second), and I was able to smoothly pan and zoom around while that was ongoing. Granted I'm on a rather powerful laptop, but for extreme scenarios like this, I think you'd want to run on powerful hardware.

My sample might be useful to you as it tries to really optimize how animation updates are done in bulk on each UI thread update, rather than hammering it on individual timer updates.

Also one thing to consider: I was using UWP and not WPF. We've found that UWP's .NET Native compiler delivers over twice as fast interop performance over the .NET Framework that WPF uses. While the interop layer normally isn't hit that hard, in these constantly updating features scenarios, you're hitting that interop layer relatively harder, and rendering performance can suffer somewhat from it. Also UWP has a much better composition layer that allows us to more efficiently render DX11 to the screen with much less overhead than WPF can do. UWP does require targeting Windows 10 though.

Also you mentioned 10.2.7 earlier. Have you tried 100.2.1 ? Lots of changes has happened since then, and we spent a lot of time improving WPF rendering performance in 100.2.1, and the upcoming 100.3 will be even better (and getting a lot closer to what UWP can deliver).

Re: Efficiently Move Polylines

ScottBrady2 — Mon, 02 Jul 2018 00:29:53 GMT

Hi Morten,

Unfortunately our application cannot be migrated to UWP as that would require a significant amount of rework with respect to the other modules.

We reviewed the 100 series and came to the conclusion that at this stage it does not support all of our requirements.

That said, we will review the 100 series and implement when more fully featured.

Kind Regards

Scott Brady

Application Developer

CISTECH SOLUTIONS

Re: Efficiently Move Polylines

dotMorten_esri — Mon, 02 Jul 2018 15:51:45 GMT

With WPF I'm still curious how that conclusion came to be, and if you possibly could share an example of how it falls short, so perhaps I could provide pointers how to improve it? There's ways to move polylines efficiently and ways to do it very inefficiently. My streaming-service-layer sample uses some best practices to frequently update graphics in a special re-used render-thread pulse (regardless of it only updating points).

Because the vertices of a polyline changes the vertex buffers needed on the graphics card, there really isn't any way for any API to efficiently "move" polylines around the same way that points can be done, so yes there's going to be an additional overhead, but we have also spent a lot of times optimizing that.

Re: Efficiently Move Polylines

ScottBrady2 — Mon, 23 Jul 2018 23:45:39 GMT

Apologies for not replying sooner.

Due to the nature of my project and its I am not permitted to share the code.

I have managed to implement lines but I am unsure as to whether I am doing it efficiently or not.

Would it be possible to have a look at your sample application such that I can compare.

I am using 10.2.7

Kind Regards

Scott

Re: Efficiently Move Polylines

dotMorten_esri — Wed, 25 Jul 2018 23:08:10 GMT

I do not have a sample for 10.2.x. The sample I have I already shared above for 100.x, which have the framework for doing efficient geometry updates. It's only updating points, but is easily extensible to polyline too without changing the actual framework.