Dynamically updating KML file based on certain conditions - kml

Question

I have developed the following network link for dynamic updates :
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
<NetworkLink>
<name>Loads TEST.kml</name>
<Link>
<href>/home/desktop/farhan/test.kml</href>
</Link>
</NetworkLink>
</kml>
Test.kml file has two placemarks.
My network link file is getting successfully updated on changes in Test.kml file
Now what I want to do is to place an 'IF' condition so that if a certain thing is true then placemark color is 'Green' Else 'Red'.
What should I do here ?? Is there any Java API I need to follow.

Answer 1

Depends how/where you want to host the KML and what those conditions are.
If the styles and conditions are static then you can generate the KML pre-set with those styles as part of the KML. For example, if you want to generate the KML based on some conditions such as population size > 100K => red, size > 50K => blue, otherwise white where each generated Placemark would have the appropriate shared share or inline style.
One popular Java-API to generate KML is the Java API for KML (or JAK for short).
If the views (based on conditions) are "dynamic" and user-selected then you have a couple of options:
Generate different versions/views of the Placemarks based on different conditions with NetworkLinks and radioFolders to load a particular view. The KML could be statically generated once or dynamically via a web-service, servlet, CGI-script, etc.
For example, the USGS has an earthquake real-time feed with multiple NetworkLinks each with a different view/color/size scheme for the same data (e.g. color by age vs magnitude).
Check out http://earthquake.usgs.gov/earthquakes/feed/earthquakes.kml
Use the Google Earth API to load, create, and modify KML in context of HTML and JavaScript with Google Earth running as a plugin in your web browser. This requires some JavaScript programming.
Use NetworkLinks as shown in your example combined with NetworkLinkControl elements to globally change the shared styles. See NetworkLinkControl tutorial. You can't add NetworkLinkControl elements to your KML directly in Google Earth so you have to author your KML manually or programmatically.

Answer 2

use php , if you are aware of it and generate kml with the help of your table and also you can use various plugins and JAK as told by jason above.
What you can do is :
connect your mysql db ( having latnlong ) through jdbc.
2 .Run a loop i.e while loop which will add placemarks as per the latitude and longitude and add other necessary element of kml like :
Element ristyle = doc.createElement("IconStyle"); // this will create an Icon.
make a new file through :
Result dest = new StreamResult(new File("file location"));
this will create your new kml file
-- place a condition here which will show your condition like a normal loop.
5 Make a network link and refer your kml file in this for manual updation.
I think this should work