Animating a line in Google Earth using kml - kml

Question

I am pretty accomplished at using the animated update function of google earth and am using it to move models around. What I would really like to do is to be able to animate a line (eg up and down) in Google Earth but am finding this tricky.
I have the longitude and latitude of the line at the start. For example line coordinates are:
-88,17,100 -88.20270841086835,17.21899813162266,100
I then want to raise one end of this line up to an altitude of 500 over a period of 5 seconds.
I've drawn the line using LineString:
<Placemark id="path1">
<name>Untitled Path man</name>
<LineString>
<tessellate>1</tessellate>
<coordinates>
-88.,17,100 -88.20270841086835,17.21899813162266,100
</coordinates>
</LineString>
</Placemark>
But Im now lost as to how to use <gx:AnimatedUpdate> to move one end up from 100 to 500.
Im sure its easy - can someone point me in the right direction??

Answer 1

The trick is to update the LineString element (with an id on that) rather than the Placemark.
Here's a working KML example tour that animates a line changing from a relative altitude of 100 to 500m.
<?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">
<Document>
<name>gx:AnimatedUpdate example</name>
<open>1</open>
<LookAt>
<longitude>-88.1351880996469</longitude>
<latitude>17.09943637744042</latitude>
<altitude>0</altitude>
<heading>49.91874373078863</heading>
<tilt>84.43764019949967</tilt>
<range>1929.311316966288</range>
<gx:altitudeMode>relativeToSeaFloor</gx:altitudeMode>
</LookAt>
<Placemark>
<name>Untitled Path man</name>
<LineString id="path1">
<tessellate>1</tessellate>
<altitudeMode>relativeToGround</altitudeMode>
<coordinates>
-88,17,100 -88.20270841086835,17.21899813162266,100
</coordinates>
</LineString>
</Placemark>
<gx:Tour>
<name>Play me!</name>
<gx:Playlist>
<gx:AnimatedUpdate>
<gx:duration>5</gx:duration>
<Update>
<targetHref/> <!-- Left empty to refer to the current file -->
<Change>
<LineString targetId="path1">
<coordinates>
-88,17,100 -88.20270841086835,17.21899813162266,500
</coordinates>
</LineString>
</Change>
</Update>
</gx:AnimatedUpdate>
<!-- Wait for the animation to complete (see the touring
tutorial for an explanation of how AnimatedUpdate's
duration isn't enough to guarantee this). -->
<gx:Wait>
<gx:duration>5.0</gx:duration>
</gx:Wait>
</gx:Playlist>
</gx:Tour>
</Document>
</kml>
For details see https://developers.google.com/kml/documentation/touring#tourtimelines