Unable to visualize large kml files in google earth - kml

Question

I am trying to use the google earth pro desktop application for visualizing IoT sensor data at different locations. Unfortunately, due to the limitations of google earth, I am unable to visualize 4GB of kml file at a time, as it throws the error "empty KML file".
I tried changing the memory cache limits under Tools -> Options -> Cache and there was no use.
I tried splitting the 4GB kml file into multiple smaller 70MB files and opening multiple files in google earth. It is becoming unresponsive and is loading very slow after opening two files.
The data is timeline data with sensor values from different locations. We need to visualize all (at least half) data so that we can use the timeline slider and see the changes over time.
It would be great to get some suggestions/alternatives to solve the issue.
Thanks.

Answer 1

If a KML file is very large then trying to display all the features at once can crash Google Earth Pro, affect performance with sluggish response, etc. Large KML files can be viewed in Google Earth if all or some of these techniques are applied to the KML.
NetworkLink
Folder Radio style or explicit visiblity=0
Number of Points per feature and geometry simplification
NetworkLink
A root .kml file can reference all the sub-KML files, but the referenced sub-files should have the visibility off so the user must manually check it to be visible. This will prevent all the data from being displayed all at once.
Here is the structure of the root KML file:
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
<Document>
<NetworkLink>
<name>NetworkLinked sub-item1</name>
<visibility>0</visibility>
<Link>
<href> kml1.kml </href>
</Link>
</NetworkLink>
<NetworkLink>
<name>NetworkLinked sub-item2</name>
<visibility>0</visibility>
<Link>
<href> kml2.kml </href>
</Link>
</NetworkLink>
...
</Document>
</kml>
Radio Folder
You can further restrict what is displayed at a given time using radio folders.
Here's a radio folder example allowing the user to only choose one of the NetworkLinks at a time. This is used when the content is mutually exclusive and only one set of features should appear at any given time.
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
<Document>
<Style id="rf">
<ListStyle>
<listItemType>radioFolder</listItemType>
</ListStyle>
</Style>
<Folder>
<name>One at a time example</name>
<open>1</open>
<description>Link 1 visible by default</description>
<styleUrl>#rf</styleUrl>
<NetworkLink>
<name>NetworkLinked sub-item-1</name>
<Link>
<href> kml1.kml </href>
</Link>
</NetworkLink>
<NetworkLink>
<name>NetworkLinked sub-item-2</name>
<visibility>0</visibility>
<Link>
<href> kml2.kml </href>
</Link>
</NetworkLink>
</Folder>
</Document>
</kml>
Number of Points per feature and geometry simplification
Size of the KML file and number of features is not the only issue to consider. A KML file with a single hi-res polygon having 350K points and 7000 inner holes can cause Google Earth performance issues. Such geometries would need to be simplified and the number of points reduced. You can use QGIS to open a KML file then apply a simplify algorithm on the polygon. In QGIS, select Vector menu -> Geometry tools -> Simplify then save the result.