Layer to KML - why some polygons not showing up in Google Earth?

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05-27-2012 10:09 PM
RenataPronk1
New Contributor II
Hi,

I've converted quite a few layers to KML files recently and had no problems, however with one layer I have converted when I open the KML file in Google Earth there were some polygons missing, and some showing up. Well, they're not completely missing, if I click on where they are meant to be I still get the pop up box with the attribute data, but they aren't actually showing up with a colour and outline.

Anyone have any thoughts?

Thanks!
Renata
6 Replies
MathewCoyle
Frequent Contributor
Does your symbology vary between different features? Are they complex line or fill graphics? Have you tried with simple symbology? Dashed lines, hatching, picture marker fills, etc. don't seem to be handled very well by google earth. They should just switch to a default simple lines/fills though.
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DarrenWiens2
MVP Honored Contributor
I've also run into this with polygons with a large number of vertices, although I'm not sure if the infowindows still appeared. Try Simplify Polygon first.

edit: I see folks posting elsewhere that KML has a vertex limit of about 30,000, although I ran into this problem with a feature class containing about 10,000. It worked fine after simplification.
MathewCoyle
Frequent Contributor
From my limited exposure to KML, I have not seen any hard vertex limit in Google Earth exactly. There is most likely a point where it takes the application too long to draw all the vertices in a particular feature on screen and times out, continuing to the next feature. This would explain how a user can still select the "invisible" features that are not displayed, as the bounding area will still be honoured.

Google Maps has a hard vertex limit as that information is stored and rendered on the Google servers, so they need to cap it.
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KevinHibma
Esri Regular Contributor
I've spent a good amount of time searching for a documented limit and could not find one.
Through testing it seems like the cap is around 30,000 vertices for a single feature.

I've also seen complex polygon featureclasses when you have more than 10,000 features have rendering issues. (I didnt hunt it down, but maybe it was a combination of many features and many vertices together as a problem).
Well we cant "fix" this issue (the KML is correct per the spec), we added a warning in ArcGIS 10.1 when creating KML, that if you have more than 30,000 vertices, not all KML may draw correctly. This way you will have a heads up and a couple of ideas on modifying your data.

However please note, ArcGIS Explorer seems to have no problem drawing 30,000+ vertices features.
RenataPronk1
New Contributor II
The simplify polygon trick worked a treat - after applying this all the polygons showed straight up in Google Earth - plus it also reduced the size of the data by quite a bit which is really useful because I was finding some of my KML files were just too huge to even load in Google Earth. Thanks so much Darren! Thanks everyone for your imput.
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tchaulla
New Contributor II

I ran into this too. Both the Simplify Polygons tool and simplifying the symbology in general didn't solve it.

Instead, I re-imported my original files and only made one change (changed the symbology), used Layer -> KML, and it worked. I'm not sure what I clicked the first time for the polygons to not show up in Google Earth as a KML. I'm writing this so that future people with this problem could try this method too.

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