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Nested KML Network Links

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4 weeks ago
GeoffroyRicher-Lalonde
Occasional Contributor II

We use a drone mapping software named WebODM that can export a large georeferenced image as a single KMZ. The KMZ created by this software is integrating tiled PNG of different levels as KML Ground Overlays.

The KMZ only contains a single Network Link that points to the first level KML. This KML contains 1 Ground Overlay and 4 Network Links :

GeoffroyRicherLalonde_0-1717012754257.png

The process is repeated for every level. At the last level, the KML only contain 1 Ground Overlay and no Network Link.

This kind of file can be used in Google Earth EC. Even if the file is very large (e.g. 200 Mo), it loads quickly thanks to the use of <Region> and <Lod> tags.

GoogleEarthEC.gif

But this kind of KMZ doesn’t load entirely in ArcGIS Earth. In fact, only the first level is loaded.

GeoffroyRicherLalonde_2-1717014288764.png

The result is a heavily pixelated image that cannot be used :

ArcGISEarth.gif

Could a next release of ArcGIS Earth be able to open this kind of nested Network Links ?

A PPTX file with more information is attached to this post. PDF files show the structure of the KMZ and a KML example (coordinates were removed).

Thank you !

Geoffroy Richer-Lalonde
GIS Specialist, Hydro-Québec
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2 Replies
XiChen
by Esri Contributor
Esri Contributor

@GeoffroyRicher-Lalonde Thank you for providing such detailed information. The dev team is now working on it. We have encountered some related issues before, and we hope to sort this out soon.

Sharon_MU
Esri Contributor

Hi @GeoffroyRicher-Lalonde ,  

We tried the WebDOM (free trail version) and reproduced this issue finally. 

ArcGIS Earth does support KML Network Link and the `onRegion` refresh method,  even if there are complicated nested relationship in between. 

However, the root reason should be that the relative path referenced in each KML Network Link is not supported well currently.  e.g. path in this format `../../1/0/0.kml` in the following lines. 



		<NetworkLink>
			<name>1/0/0.png</name>
			<Region>
				<Lod>
					<minLodPixels>128</minLodPixels>
					<maxLodPixels>-1</maxLodPixels>
				</Lod>
				<LatLonAltBox>
					<north>46.842667</north>
					<south>46.842120</south>
					<east>-91.993928</east>
					<west>-91.994754</west>
				</LatLonAltBox>
			</Region>
			<Link>
				<href>../../1/0/0.kml</href>
				<viewRefreshMode>onRegion</viewRefreshMode>
				<viewFormat/>
			</Link>
		</NetworkLink>

 

In the level 0,  the kml path contains no "../",  so the level 0 is available.  It was also consistent with your observation.

We're still working on this issue and will keep you updated.  

Thanks again for reporting such valuable feedback.

Sharon

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