topic Re: KmlLayer does not display images in ArcGIS API for Silverlight Questions

KmlLayer does not display images

NataliaEvsyuchenya — Sun, 22 Jan 2012 07:28:55 GMT

Hello!

I am try to add KmlLayer to the Map. I place kmz file at the C:\inetpub\wwwroot\KML_TEST_FILES\. If unzip the my kmz file you can see:

[INDENT]<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2" xmlns:kml="http://www.opengis.net/kml/2.2" xmlns:atom="http://www.w3.org/2005/Atom">
<GroundOverlay>
<name>????????? ??? ????????</name>
<Icon>
<href>files/4_9.jpg</href>
<viewBoundScale>0.75</viewBoundScale>
</Icon>
<LatLonBox>
<north>52.95165833333334</north>
<south>52.70903611111112</south>
<east>27.76611666666667</east>
<west>27.37067500000001</west>
</LatLonBox>
</GroundOverlay>
</kml>
[/INDENT]

I add the following code to my page:

              [INDENT] public MainPage()
{
   InitializeComponent();
                        Map.Layers.Add(new KmlLayer()
                                                       {
                                                              Url = new Uri("http://localhost/KML_TEST_FILES/radar.kmz"),
                                                              ID = "Kml layer"
                                                        });
}
[/INDENT]

There is no errors but image is not shown on the map. What's the problem?

Re: KmlLayer does not display images

JenniferNery — Mon, 23 Jan 2012 02:38:14 GMT

Have you looked at this blog post: http://blogs.esri.com/Dev/blogs/silverlightwpf/archive/2009/08/24/Troubleshooting-blank-layers.aspx?

Re: KmlLayer does not display images

DominiqueBroux — Mon, 23 Jan 2012 08:14:32 GMT

Which ArcGIS SL version are you using?

Only the 2.3 version takes care of GroundOverlays.

Also does the file 'files/4_9.jpg' exist in the kmz file (after unzipping as you did)?

Re: KmlLayer does not display images

NataliaEvsyuchenya — Mon, 23 Jan 2012 15:36:04 GMT

Which ArcGIS SL version are you using?

Only the 2.3 version takes care of GroundOverlays.

Also does the file 'files/4_9.jpg' exist in the kmz file (after unzipping as you did)?

I have the 2.3 version installed. And file "files/4_9.jpg" exists.

Re: KmlLayer does not display images

NataliaEvsyuchenya — Mon, 23 Jan 2012 15:42:26 GMT

Have you looked at this blog post: http://blogs.esri.com/Dev/blogs/silverlightwpf/archive/2009/08/24/Troubleshooting-blank-layers.aspx?

I run the Fiddler2, but there is no errors. You can see screenshot [ATTACH=CONFIG]11365[/ATTACH]. And also layer appears in the Map legend.

Re: KmlLayer does not display images

DominiqueBroux — Tue, 24 Jan 2012 08:29:35 GMT

Could you share the KMZ file so I can test with it?

Thanks

Re: KmlLayer does not display images

NataliaEvsyuchenya — Tue, 24 Jan 2012 09:37:42 GMT

Could you share the KMZ file so I can test with it?

Thanks

http://ge.tt/8Igs2hC?c

Re: KmlLayer does not display images

DominiqueBroux — Tue, 24 Jan 2012 10:49:03 GMT

Thanks for the link.

From my tests, it's working. You can test it here with the KML Viewer using the version 2.3 of the API.

Re: KmlLayer does not display images

NataliaEvsyuchenya — Tue, 24 Jan 2012 11:17:50 GMT

Thanks for the link.

From my tests, it's working. You can test it here with the KML Viewer using the version 2.3 of the API.

Could you show your code, please. Maybe the problem that I use localhost? Do you have any ideas?

Re: KmlLayer does not display images

DominiqueBroux — Tue, 24 Jan 2012 11:33:23 GMT

Could you show your code, please.

The code is published here .

Maybe the problem that I use localhost?

Localhost should not be the problem. Nevertheless feel free to test your program with this public Url : http://broux.dominique.free.fr/Silverlight/test/radar.kmz

Do you have any ideas?

No idea. Just double check that you are using the 2.3 final (version 2.3.0.746)

Re: KmlLayer does not display images

NataliaEvsyuchenya — Tue, 24 Jan 2012 17:36:58 GMT

I could display image when I set for Basic Layer Url = "http://server.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer" instead of "http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer". But why KmlLayer depends on Basic Layer?

Re: KmlLayer does not display images

DominiqueBroux — Tue, 24 Jan 2012 17:54:58 GMT

I could display image when I set for Basic Layer Url = "http://server.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer" instead of "http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer". But why KmlLayer depends on Basic Layer?

That rings a bell.
The extent of the images is set with the geographical coordinates found in the KML file but this extent is not the right one when your map is using projected coordinates.

In fact, KML Groundoverlays don't support autoprojection to non geographic coordinates. It's identified as a possible future enhancement but not planned at this time.

It's probably possible to project the extent by yourself (not tested and probably not that easy though):
- go through the KML layer hierachy to find all ElementLayers
- for each ElementLayer, loop on the elements
- for each element, project the extent from Geographical coordinates to Mercator

Sorry I should have thought about that sooner.

Re: KmlLayer does not display images

HumzaAkhtar — Wed, 17 Apr 2013 03:59:01 GMT

That rings a bell.
The extent of the images is set with the geographical coordinates found in the KML file but this extent is not the right one when your map is using projected coordinates.

In fact, KML Groundoverlays don't support autoprojection to non geographic coordinates. It's identified as a possible future enhancement but not planned at this time.

It's probably possible to project the extent by yourself (not tested and probably not that easy though):
- go through the KML layer hierachy to find all ElementLayers
- for each ElementLayer, loop on the elements
- for each element, project the extent from Geographical coordinates to Mercator

Sorry I should have thought about that sooner.

Hi,

Is the issue you mentioned in your post solved in the new runtime API 10.1.1 ?

Thanks and Regards
Humza

Re: KmlLayer does not display images

DominiqueBroux — Wed, 19 Nov 2014 11:30:08 GMT

For the WebMercator case and images that cover a small area, this has been fixed in the ArcGIS for WPF version 10.1.1 and ArcGIS for Silverlight version 3.1.

For others map spatial references, it's not fixed. The workaround may be to project the groundoverlay extent by yourself by using a geometry service. This may make sense for SpatialReferences whose the projection of a WGS84 envelope is also an envelope (i.e a projection where meridians and parallels are perpendicular straight lines).

But anyway this will not be accurate for images that cover a large area (due to the image distorsion)