topic Re: GetFullExtent zooming out, but Dynamic Layers are blank in ArcGIS API for Silverlight Questions

GetFullExtent zooming out, but Dynamic Layers are blank

KevinSesock — Fri, 18 Feb 2011 14:14:02 GMT

We're not sure if this has to do with our service, or with our silverlight viewer, but we have an issue with when zooming out to the full extent of our map, set by the ConstrainFullExtent property, we have an issue where our dynamic layers disappear. This seems to be similar to this issue, here:

http://forums.arcgis.com/threads/18071-Graphic-objects-disappearing-when-zoom-in-out?highlight=Layers+disappear

As in one of our other maps (currently on API 2.0), we have the issue where when full zoomed out, zooming in requires several mouse clicks that don't seem to zoom you in very fast.

Both maps seem to have an issue where our Dynamic layer "disappears" at full extent. This is most easily replicated by Map.ZoomTo(Map.Layers.GetFullExtent()); (in our Legacy Toolbar, the Full Extent button).

Our map experiencing this issue, is here:

http://www.owrb.ok.gov/learn/GWQ-sl/

You may have to adjust your browser size, as it doesn't do this at all browser sizes.

Re: GetFullExtent zooming out, but Dynamic Layers are blank

JenniferNery — Fri, 18 Feb 2011 17:21:03 GMT

Please go through this blog post for troubleshooting blank layers http://blogs.esri.com/Dev/blogs/silverlightwpf/archive/2009/08/24/Troubleshooting-blank-layers.aspx. Fiddler might be able to tell us whether a web request for that layer was sent or not and if any failure had occurred.

Re: GetFullExtent zooming out, but Dynamic Layers are blank

KevinSesock — Fri, 18 Feb 2011 19:14:08 GMT

No dice on any of these. Let me be clear, I can see all of my layers, except when zoomed to full extent.

Re: GetFullExtent zooming out, but Dynamic Layers are blank

DanielWalton — Sun, 12 Dec 2021 04:36:01 GMT

Weird problem. Are you ignoring any exceptions anywhere in your app? E.g.

try 
{
//code
}
catch
{
//empty catch block
}

Also, it might be related to the way your map control extent and layer extents are set up. Couldn't say much more without seeing some code.

Re: GetFullExtent zooming out, but Dynamic Layers are blank

DominiqueBroux — Mon, 21 Feb 2011 19:19:09 GMT

Hi Kevin,

I tried to reproduce your issue, but I don't understand what type of constrainextentbehavior you set up.

It looks like we are not able to zoom out after reaching the full extent (normal), but we are able to pan outside this extent(and then even zoom out to a large extent). This looks strange to me.

Could you help me on this point?

Thanks

Re: GetFullExtent zooming out, but Dynamic Layers are blank

KevinSesock — Sun, 12 Dec 2021 04:36:04 GMT

           <esri:Map x:Name="BaseWIMS" IsLogoVisible="False" ExtentChanged="BaseWIMS_ExtentChanged" Extent="-98.220507, 36.188768, -96.225105, 34.716448" MouseClick="QueryPoint_MouseClick" >
                <i:Interaction.Behaviors>
                    <esri:MaintainExtentBehavior />
                    <esri:ConstrainExtentBehavior ConstrainedExtent="-98.220507, 36.188768, -96.225105, 34.716448" />
                </i:Interaction.Behaviors>
                <esri:ArcGISTiledMapServiceLayer ID="BaseLayer" Url="http://server.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer" />
                <esri:ArcGISDynamicMapServiceLayer ID="BoundaryLayer" Url="http://rest.owrb.ok.gov/ArcGIS/rest/services/Special_Studies/Garber_GWQ_Max_Metals_Boundary_WGS84/MapServer"  Opacity=".85"/>
                <esri:ArcGISDynamicMapServiceLayer ID="CountyLayer" Url="http://rest.owrb.ok.gov/ArcGIS/rest/services/Base/SDE_State_County_PLSS_WGS84/MapServer" InitializationFailed="CountyLayer_InitializationFailed" Opacity=".9"/>
                <esri:ArcGISDynamicMapServiceLayer ID="DynamicLayer" Url="http://rest.owrb.ok.gov/ArcGIS/rest/services/Special_Studies/Garber_GWQ_Max_Metals_WGS84/MapServer" Initialized="ArcGISDynamicMapServiceLayer_Initialized" InitializationFailed="ArcGISDynamicMapServiceLayer_InitializationFailed" />
                <esri:GraphicsLayer ID="GraphicsLayer" />
            </esri:Map>

For reference, BaseWIMS_ExtentChanged is for the ToolbarWidget. It does have a Try/Catch block but I'm not seeing any exceptions.

I have a UserControl_Loaded method that is wired up to "Loaded" on the root UserControl object in the XAML, and here's what it's doing:

        private void UserControl_Loaded(object sender, RoutedEventArgs e)
        {
            //Show disclaimer at startup, after splash screen.
            lblDisclaimer_Link(sender, e);
            BaseWIMS.MinimumResolution = .0001;
   //Fix for broken ConstrainExtentBehavior in SL4.
            /*System.Windows.Interactivity.Behavior behavior = new ESRI.ArcGIS.Client.Behaviors.ConstrainExtentBehavior()
            {
                ConstrainedExtent = new ESRI.ArcGIS.Client.Geometry.Envelope(-98.220507, 36.188768, -96.225105, 34.716448)
            };
            System.Windows.Interactivity.Interaction.GetBehaviors(BaseWIMS).Add(behavior); */
            BaseWIMS.Cursor = Cursors.Hand;
        }

As you can see, I did have an issue with the 2.0 API that had to do with ConstrainExtentBehavior (from what I recall this was a known issue), but this seems to be working in 2.1, so I've commented the code.

Other than that, I'm not sure what would be causing this issue.

Re: GetFullExtent zooming out, but Dynamic Layers are blank

DominiqueBroux — Tue, 22 Feb 2011 13:22:09 GMT

Hi Kevin,

Yours YMin and Ymax are reversed:

<esri:ConstrainExtentBehavior ConstrainedExtent="-98.220507, 36.188768, -96.225105, 34.716448" />

That being said, I am not sure this will solve your issue (I was not able to reproduce it), but at least this will prevent to pan outside the constraint extent.
So I think it's worth the try after fixing the order.

If you still get the issue, could you test without the 'MaintainExtentBehavior'?

Re: GetFullExtent zooming out, but Dynamic Layers are blank

KevinSesock — Tue, 22 Feb 2011 14:07:08 GMT

Reversing the YMin and YMax actually made it worse (it was doing the same thing further out and zooming in was very... clunky, for lack of a better word).

Taking out the ConstrainExtentBehavior however, definitely resolved the issue. The dynamic layers are displaying at all resolutions now. However, I can't have my full extent be the maximum extent of the base map layer (in other words, the entire world).

Would you like me to upload with the reversed YMin and YMax so you can see the effects?

Re: GetFullExtent zooming out, but Dynamic Layers are blank

DominiqueBroux — Tue, 22 Feb 2011 14:28:51 GMT

Would you like me to upload with the reversed YMin and YMax so you can see the effects?

Yes, please, this might help me to have a clue.

Did you test without the MaintainExtentBehavior as well?

And could you test without the BaseWIMS_ExtentChanged as well?

Thanks

Re: GetFullExtent zooming out, but Dynamic Layers are blank

KevinSesock — Sun, 12 Dec 2021 04:36:06 GMT

New version uploaded to http://www.owrb.ok.gov/learn/GWQ-sl/

This has no MaintainExtentBehavior (taking it out didn't seem to change anything), and I put ConstrainExtentBehavior back into the XAML and took it out of the UserControl_Loaded method in the code-behind.

This is what I have at the moment:

            <esri:Map x:Name="BaseWIMS" IsLogoVisible="False" ExtentChanged="BaseWIMS_ExtentChanged" Extent="-98.220507, 34.716448, -96.225105, 36.188768" MouseClick="QueryPoint_MouseClick" >
                <i:Interaction.Behaviors>
                    <!-- <esri:MaintainExtentBehavior />-->
                    <esri:ConstrainExtentBehavior ConstrainedExtent="-98.220507, 34.716448, -96.225105, 36.188768" />
                </i:Interaction.Behaviors>
                <esri:ArcGISTiledMapServiceLayer ID="BaseLayer" Url="http://server.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer" />
                <esri:ArcGISDynamicMapServiceLayer ID="BoundaryLayer" Url="http://rest.owrb.ok.gov/ArcGIS/rest/services/Special_Studies/Garber_GWQ_Max_Metals_Boundary_WGS84/MapServer"  Opacity=".85"/>
                <esri:ArcGISDynamicMapServiceLayer ID="CountyLayer" Url="http://rest.owrb.ok.gov/ArcGIS/rest/services/Base/SDE_State_County_PLSS_WGS84/MapServer" InitializationFailed="CountyLayer_InitializationFailed" Opacity=".9"/>
                <esri:ArcGISDynamicMapServiceLayer ID="DynamicLayer" Url="http://rest.owrb.ok.gov/ArcGIS/rest/services/Special_Studies/Garber_GWQ_Max_Metals_WGS84/MapServer" Initialized="ArcGISDynamicMapServiceLayer_Initialized" InitializationFailed="ArcGISDynamicMapServiceLayer_InitializationFailed" />
                <esri:GraphicsLayer ID="GraphicsLayer" />
            </esri:Map>

Re: GetFullExtent zooming out, but Dynamic Layers are blank

KevinSesock — Wed, 23 Feb 2011 13:32:05 GMT

Any further thoughts?

Re: GetFullExtent zooming out, but Dynamic Layers are blank

DanielWalton — Wed, 23 Feb 2011 13:36:42 GMT

Have you tried expanding the constraint extents out some to see if it goes away? Or shrinking them down a bit to contain all the service layers extents? I think the problem lies in you having defined so many different extents (on the map, the service, and the sublayers). Just a guess though.

Re: GetFullExtent zooming out, but Dynamic Layers are blank

KevinSesock — Wed, 23 Feb 2011 16:43:16 GMT

Just did. It actually seems to make it worse. If we go in further that seems to help some. Here is my question at this point:

We have three dynamic layers. Two of which are for these wells we're showing, one of which contains the county and PLSS boundaries for the entire state. The two well layers are set to the same extent (in ArcMap, they're set to the maximum extent of the visible layers), and the same of the PLSS layer, but it's set to a much larger extent (as it takes up the entire state). Setting every service to the same (as the PLSS service), and changing our ConstrainedExtent to match improves the situation, but it's still not perfect.

Removing the PLSS service from the layers doesn't seem to help, either. The only thing that causes this to stop is removing the ConstrainedExtentBehavior, but then unfortunately we don't have any option to Constrain the Extent. Can anyone confirm this as a bug?

Re: GetFullExtent zooming out, but Dynamic Layers are blank

DominiqueBroux — Sun, 12 Dec 2021 04:36:09 GMT

Hi Kevin,

I eventually reproduced your issue with 2.1.

The good news (let's begin with this one:)) is that I was not able to reproduce the issue with the current version I am working with, so hopefully this will work well with the next version (2.2).

The less good news is that I have had hard time to find out a workaround, and I am not sure the workaround I found covers all cases (but I think it makes things much better anyway).

To test the workaround:
- Remove the ConstraintExtentBehavior
- Wire up the extentchanged and extentchanging events of the map to the following ConstraintExtent code:

private Envelope _constrainedExtent = null;
private bool _hasExtentBeenSet = false;
private Envelope _lastExtent = null;
private void ConstraintExtent(object sender, ExtentEventArgs e)
{
var map = sender as Map;
if (map == null) return;
Envelope newExtent = e.NewExtent.Clone();
 
if (_constrainedExtent == null) // In this sample : initialize contrainted extent to first the extent
_constrainedExtent = newExtent;
 
if ((newExtent.XMin >= _constrainedExtent.XMin && newExtent.XMax <= _constrainedExtent.XMax && // completely within
newExtent.YMin >= _constrainedExtent.YMin && newExtent.YMax <= _constrainedExtent.YMax) ||
(newExtent.XMin >= _constrainedExtent.XMin && newExtent.XMax <= _constrainedExtent.XMax && // width within and height outside
newExtent.YMin <= _constrainedExtent.YMin && newExtent.YMax >= _constrainedExtent.YMax) ||
(newExtent.XMin <= _constrainedExtent.XMin && newExtent.XMax >= _constrainedExtent.XMax && // height within and width outside
newExtent.YMin >= _constrainedExtent.YMin && newExtent.YMax <= _constrainedExtent.YMax))
{
if (_hasExtentBeenSet)
{
_hasExtentBeenSet = false;
map.ZoomTo(newExtent.Expand(0.999)); // hack to force the refresh of the layers
}
return;
}
 
if (newExtent.Equals(_lastExtent))
return;
 
_lastExtent = newExtent;
 
if (newExtent.Width <= _constrainedExtent.Width && newExtent.Height <= _constrainedExtent.Height)
{
// Pan enough  to respect constraint
double dx = Math.Min(_constrainedExtent.XMax - newExtent.XMax, Math.Max(_constrainedExtent.XMin - newExtent.XMin, 0));
double dy = Math.Min(_constrainedExtent.YMax - newExtent.YMax, Math.Max(_constrainedExtent.YMin - newExtent.YMin, 0));
newExtent.XMin += dx; newExtent.XMax += dx;
newExtent.YMin += dy; newExtent.YMax += dy;
map.PanTo(newExtent);
}
else
{
// Change extent to respect constraint
newExtent = newExtent.Intersection(_constrainedExtent);
map.Extent = newExtent;
_hasExtentBeenSet = true;
}
}

Hope this help.

Re: GetFullExtent zooming out, but Dynamic Layers are blank

KevinSesock — Wed, 23 Feb 2011 18:17:06 GMT

We're dialing in the initial extent that works best. The behavior of both the behavior and this event handler seems erratic, but there seems to be no reason for that. At one initial extent, there's nothing drawn, at another, it works perfectly all the way through. We'll get it dialed in, however, and let you know.

Any kind of ETA on that 2.2 API? 😉

Re: GetFullExtent zooming out, but Dynamic Layers are blank

JenniferNery — Wed, 23 Feb 2011 22:18:49 GMT

We also are not aware of ETA for v2.2, we just know that it may be soon:) From dev team, it goes through a series of approval and processing from other teams so potential due date is hard to tell.

Re: GetFullExtent zooming out, but Dynamic Layers are blank

KevinSesock — Thu, 24 Feb 2011 12:08:01 GMT

We would be happy to volunteer for beta testing! Seriously, though, thanks for the help. This code above will more than suffice for the time being until 2.2 comes out.