topic Re: ArcGISLocalDynamicMapServiceLayer PanBuffer? in ArcGIS Runtime SDK for WPF (Retired) Questions

ArcGISLocalDynamicMapServiceLayer PanBuffer?

JamesMcElroy — Thu, 02 Aug 2012 10:42:23 GMT

The PanBuffer property in the Beta allowed for smooth panning around a dynamic map layer (ie. no or little white space while waiting for refresh). While you can still find this in the online documentation here, it appears to have been removed for the release version.

So my question is this, how can I get my map object to pan in a smoother fashion without having constant white space while it's waiting to load and refresh?

Thanks,

James

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

MichaelBranscomb — Fri, 03 Aug 2012 07:41:45 GMT

Hi,

We decided that the PanBuffer behavior was inconsistent with other the dynamic service layer types in the API (and with dynamic layer behavior in the other Runtime SDKs) and therefore removed the property prior to the final release. It seems there are however orphaned PanBuffer API reference topics which appear when searching for that term. Thank you for bringing this to our attention and I apologize for any confusion this has caused.

Your basemap layers if implemented as tiled layers (represented by the ArcGISTiledMapServiceLayer and ArcGISLocalTiledLayer classes) should always provide a near-seamless panning experience. Dynamic layers will always be drawn on demand based on the requested map extent (the PanBuffer was simply just requesting a larger extent than the current map window).

Cheers

Mike

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

JamesMcElroy — Fri, 03 Aug 2012 21:18:10 GMT

Hi Mike,

Thanks for the response. So the answer is no on the alternative method then? Is there no way to manually request a larger extent than the control size?

On a related note, is there a way to enable some sort of caching on the client control side? It seems odd that if I pan to the left and then immediately back to the right that I have to wait for the place I was just on to load again. Of course this is in respect to the dynamic map packs.

Thanks,

James

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

IanBates — Wed, 02 Apr 2014 12:19:06 GMT

Hi

I just found the following in an old post. We have an identical request from a client - they would like ArcGISLocalDynamicMapService layer to have a pan buffer for smooth panning. Is there any workaround in the current version (10.2) of the WPF runtime?

Thanks for the response. So the answer is no on the alternative method then? Is there no way to manually request a larger extent than the control size?

Thanks

Ian

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

MichaelBranscomb — Thu, 03 Apr 2014 15:56:55 GMT

Hi,

There is currently no direct option in the API for requesting an extent larger than the map from an ArcGISDynamicMapServiceLayer and preventing requests until the Map extent nears this larger envelope. Ideally you would use an ArcGISTiledMapServiceLayer or an ArcGISLocalTiledLayer to meet this requirement.

However, I am investigating possible solutions based on the DynamicMapServiceLayer / DynamicLayer and will update this thread as soon as i have more information.

Cheers

Mike

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

IanBates — Mon, 16 Jun 2014 15:17:47 GMT

There is currently no direct option in the API for requesting an extent larger than the map from an ArcGISDynamicMapServiceLayer and preventing requests until the Map extent nears this larger envelope. Ideally you would use an ArcGISTiledMapServiceLayer or an ArcGISLocalTiledLayer to meet this requirement.

However, I am investigating possible solutions based on the DynamicMapServiceLayer / DynamicLayer and will update this thread as soon as i have more information.

Back in March I got a reply suggesting that you would investigate some possible solutions for smooth panning of dynamic map services based on the DynamicMapServiceLayer / DynamicLayer. I would appreciate any suggestions of how this could be achieved. This is currently a show stopper for our product. Our client demands this functionality.

If you are able to suggest some other workaround - we would be grateful. Or if this can be achieved via an upgrade path to a new esri product - we need some kind of response for our client.

Thanks

Ian

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

MatthewPilgrim — Mon, 16 Jun 2014 15:18:34 GMT

Mike, any updates - this issue is killing a potential product!

We need smooth panning of dynamic data in an offline WPF application. We would even consider moving to the .net api if this was included in the beta...

Thanks, Matt

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

MichaelBranscomb — Thu, 19 Jun 2014 14:21:45 GMT

Hi,

Apologies for the delay. The support guys will be in touch with the same info... One of the developers put together a sample demonstrating how you could implement the behaviour you are looking for by deriving from DynamicLayer (attached).

As previously discussed on this thread, the layers which are specifically designed to provide a seamless panning experience are the ArcGISTiledMapServiceLayer and ArcGISLocalTiledLayer, therefore ideally you would be able to use one of those, or perhaps consider using a FeatureLayer for some of the more dynamic data if necessary (depending volume of data, geometry type, etc).

Cheers

Mike

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

IanBates — Tue, 05 Aug 2014 15:45:08 GMT

Hi,

Thanks for the sample and sorry it has taken a while to get around to using it.

We encountered two issues with using the sample so far:

1. We cannot use the BufferedArcGISDynamicMapServiceLayer class in a Map where Accelerated Display layers is enabled (it throws an exception on intialization) This is a major issue for us as we encountered differences in behavior with Feature Editing using the EditorWidget when Accelerated Display Layers are disabled. Is there a workaround so that we can use the class in a map with Accelerated Display layers?

2. The class ignores the current TimeExtent information on the host Map. Our application uses TimeExtent information - so the BufferedArcGISDynamicMapServiceLayer needs to be time aware - can you suggest a way of implementing this? I took a look at esri help resources at this is not obvious.

Regards

Ian

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

MichaelBranscomb — Wed, 06 Aug 2014 14:07:10 GMT

Hi,

Unfortunately it is not possible to make the modification for the accelerated display mode.

This leave two options:

1. Use an ArcGISLocalTiledLayer (as suggested previously - but I cannot recall why this is not a viable option in your solution). They can take some time to generate and do take up more space on disk but the performance benefits typically far outweigh these downsides.

2. Try the new .NET SDK beta which should handle these frequent pan requests more gracefully (but still will not generate a larger dynamic layer image extent than the extent of the map). Again in this case we advise using an ArcGISLocalTiledLayer for a seamless panning experience.

We are aware of the drawbacks of Tile Packages and on the longer term roadmap for the new .NET SDK we are looking at introducing vector basemaps which will combine seamless panning and richer dynamic rendering with a smaller disk footprint and reduced generation time.

Cheers

Mike

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

IanBates — Wed, 06 Aug 2014 14:15:46 GMT

It is possible (but a little difficult to implement ) we can workaround the Accelerated Mode restriction - however we cannot use the sample unless we can solve how to make it TimeExtent Aware / supporting temporal data in the mpk. At present the sample ignores TimeExtent on the map - can you suggest how to modify the "BufferedArcGISDynamicMapServiceLayer" sample to respect the current time extent on the host map?

Thanks

Ian

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

MichaelBranscomb — Fri, 08 Aug 2014 12:39:08 GMT

Hi,

I have spent some time investigating how we can get the custom layer to respect the time extent of the map. Unfortunately the map determines which layers can honour the map's time extent via an internal interface, therefore it is not directly possible to have the layer respect the map's time extent. However - I am just pursuing another avenue - injecting the time parameter into the request URL.

Cheers

Mike

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

MichaelBranscomb — Fri, 08 Aug 2014 14:23:41 GMT

Hi,

Hopefully some good news for you - by taking a different approach with the buffered dynamic layer (with some support from a couple of the devs on the team here) we have managed to get the buffered dynamic layer with the accelerated display and time aware support you were looking for. The code for updated custom layer below - not necessarily the most elegant code but I am aware you are under time pressure therefore I wanted to get it to you as soon as I had confirmed basic functioning. you will likely need to make some tweaks to this to make it work in your app. I will send your contact in tech support (Pete) a zipped up project which demonstrates how you might tie it in with the TimeSlider control from the toolkit and he can forward to you.

Cheers

Mike

using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection;
using System.Windows.Media;
using ESRI.ArcGIS.Client;
using ESRI.ArcGIS.Client.Geometry;
using System.Globalization;


namespace CustomDynamicLayer
{
    /// <summary>
    /// This layer is a DynamicLayer that displays an ArcGIS dynamic map service, while maintaining a buffer of imagery outside the visible extent in order to 
    /// reduce the number of requests made to the server.
    /// When the map is panned but the newly visible map extent is still within the extent of previously-requested imagery*, no new request is made to the
    /// dynamic map service.
    /// 
    /// *NB: the extent that is checked when suppressing new requests is smaller than the extent that is then requested, this is to trigger new requests before "blank" areas 
    /// of the map are exposed.
    /// 
    /// Diagram showing visible extent, the extent that gets requested, and the smaller extent inside which no new request is made.
    /// 
    /// +----------------------------------------------+
    /// | extent requested from server                 |
    /// |     +----------------------------------+     |
    /// |     |requests suppressed               |     |
    /// |     |      +--------------------+      |     |
    /// |     |      | visible extent     |      |     |
    /// |     |      |                    |      |     |
    /// |     |      |                    |      |     |
    /// |     |      |                    |      |     |
    /// |     |      |                    |      |     |
    /// |     |      |                    |      |     |
    /// |     |      +--------------------+      |     |
    /// |     |                                  |     |
    /// |     +----------------------------------+     |
    /// |                                              |
    /// +----------------------------------------------+
    /// 
    /// After panning to the east, there's still no new request made because the visible extent is still inside the 'requests suppressed' extent:
    /// 
    /// +----------------------------------------------+
    /// |cached image requested from server            |
    /// |     +----------------------------------+     |
    /// |     | requests suppressed              |     |
    /// |     |            +--------------------++     |
    /// |     |            | visible extent     ||     |
    /// |     |            |                    ||     |
    /// |     |            |                    ||     |
    /// |     |            |                    ||     |
    /// |     |            |                    ||     |
    /// |     |            |                    ||     |
    /// |     |            +--------------------++     |
    /// |     |                                  |     |
    /// |     +----------------------------------+     |
    /// |                                              |
    /// +----------------------------------------------+
    /// 
    /// When visible extent moves outside "requests suppressed", then a new expanded extent is requested from the server.
    /// 
    /// </summary>
  internal class BufferedArcGISDynamicMapServiceLayerByUrl : DynamicMapServiceLayer
    {
        /// <summary>
        /// Contained layer we use to hit the server.
        /// </summary>
        public ArcGISDynamicMapServiceLayer _layer;


        /// <summary>
        /// Extent inside which the map can be panned without triggering a new request
        /// </summary>
        private Envelope _suppressRequestsExtent;


        /// <summary>
        /// Resolution of cached imagery
        /// </summary>
        private double _requestedResolution;
       
        private ImageResult _cachedResult;
        private string _cachedUrl;


        /// <summary>
        /// List of callbacks waiting to be called.
        /// </summary>
        List<OnUrlComplete> _callbacks = new List<OnUrlComplete>();


        private ImageParameters _adjustedProperties;


  public BufferedArcGISDynamicMapServiceLayerByUrl()
        {
            _layer = new ArcGISDynamicMapServiceLayer();
            _layer.Initialized += ContainedLayerInitialized;
            _layer.InitializationFailed += ContainedLayerInitializationFailed;
        }


        public override void Initialize()
        {
            _layer.Initialize();
        }


        private void ContainedLayerInitializationFailed(object sender, EventArgs e)
        {
            InitializationFailure = _layer.InitializationFailure;
            base.Initialize();
        }


        private void ContainedLayerInitialized(object sender, EventArgs e)
        {
            SpatialReference = _layer.SpatialReference;
            SupportsRotation = _layer.SupportsRotation;
            base.Initialize();
        }


        public string Url
        {
            get { return _layer.Url; }
            set { _layer.Url = value; }
        }


        double GetImageParametersResolution(ImageParameters properties)
        {
            return properties.Extent.Width / properties.Width;
        }


        public override void GetUrl(ImageParameters properties, OnUrlComplete onComplete)
        {
            // calculate if the requested extent can be dealt with without a new HTTP request
            bool requestedExtentIsContainedInExistingImagery = _suppressRequestsExtent.Contains(properties.Extent);
            bool resolutionMatchesExistingImagery = Math.Abs(GetImageParametersResolution(properties) - _requestedResolution) < 0.1;


            if (requestedExtentIsContainedInExistingImagery && resolutionMatchesExistingImagery)
            {
                _layer.GetUrl(_adjustedProperties, (url, res) =>
                {
  _cachedUrl = url + "&time="
  + MillisecondsSinceEpoch(Map.TimeExtent.Start)
  + ","
  + MillisecondsSinceEpoch(Map.TimeExtent.End)
  + "&imageSR=" + Map.SpatialReference.WKID.ToString()
  + "&bboxSR=" + Map.SpatialReference.WKID.ToString();
                    _cachedResult = res;
                    onComplete(_cachedUrl, _cachedResult);
                });
            }
            else
            {
                // A new image needs to be requested to cover the map
                
                // Add a buffer around the requested extent
                Envelope bufferedExtent = properties.Extent.Expanded(properties.Extent.Width/2,
                    properties.Extent.Height/2);
                _adjustedProperties = new ImageParameters(bufferedExtent, properties.Width*2, properties.Height*2)
                {
                    Dpi = properties.Dpi,             
                    Rotation = properties.Rotation,
                    WrapAround = properties.WrapAround
                };


                // Store new 'covered extent' and resolution now, otherwise if new getsource calls are made we might re-request new images that would have been covered by this one.
                _suppressRequestsExtent = properties.Extent.Expanded(properties.Extent.Width/3, properties.Extent.Height/3);
                _requestedResolution = GetImageParametersResolution(_adjustedProperties);


  _layer.GetUrl(_adjustedProperties, (url, res) =>
  {
  url += "&time="
  + MillisecondsSinceEpoch(Map.TimeExtent.Start)
  + ","
  + MillisecondsSinceEpoch(Map.TimeExtent.End)
  + "&imageSR=" + Map.SpatialReference.WKID.ToString()
  + "&bboxSR=" + Map.SpatialReference.WKID.ToString();
  onComplete(url, res);
  });
            }
        }


  private string MillisecondsSinceEpoch(DateTime myDateTime) 
  {
  //return myDateTime.ToUniversalTime().Subtract(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds;
  DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
  return ((myDateTime).ToUniversalTime() - epoch).TotalMilliseconds.ToString(CultureInfo.InvariantCulture);
  }
    }
}

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

IanBates — Fri, 08 Aug 2014 14:30:18 GMT

Mike,

Thanks very much for helping us with this - and all the better that it works with Accelerated Display Mode on.

We will start investigating how we can use this in our app immediately.

Regards

Ian

Re: ArcGISLocalDynamicMapServiceLayer PanBuffer?

MichaelBranscomb — Fri, 08 Aug 2014 14:35:16 GMT

Hi,

I have attached the app to this post - it might take a while to get through via email.

Good luck.

Cheers

Mike