This demo demonstrates how you can display and update data within Google Earth with FME Server's Data Streaming service and the KML Network Link Control. Using this combination, placemarks are first loaded into Google Earth from FME Server. Next Google Earth requests from FME Server any updates to the placemarks (add, modify, delete) and then applies the updates to the placemarks. So for a given update only a small amount of data needs to be processed by FME Server and Google Earth rather than the entire dataset.
This example shows realtime updates of street intersection statuses in Google Earth.
Viewing the Example
This example is set up and running on Safe's FME Server demo site. You need to have Google Earth installed to run the example.
You can try it out by opening the KML file below. The KML file contains two Network Links that point at two FME Server services. The first Network Link requests the placemarks from FME Server and the second Network Link requests updates to the placemarks from FME Server.
How It Works
Two workspaces are designed using FME Desktop (Workbench), published to FME Server and registered with the Data Streaming service. The services are then referenced from a KML Network Link file.
Initial Display of Street Intersections (D007-kml-initial-loader.fmw)
The first workspace reads street intersection locations from a database, restructures the content and outputs styled KML. When published to FME Server it is registered with the Data Streaming service.
Update Street Intersections (D007-kml-update-controller.fmw)
The second workspace accepts a KML cookie containing the last time updates were requested (as a published parameter), uses this time in order to read the changes to the street intersection statuses from a database, restructures the content, creates a KML cookie to indicate the last time updates were requested and outputs KML containing the updates and a KML Network Link Control. When published to FME Server it is registered with the Data Streaming service.
Setting up the Example
To actually set up and run the example on your own system requires a certain set of software and setup.
- Google Earth
- FME Server 2010+
- FME Desktop 2010+
- workspaces and required files
- Download the workspaces and required files in the attached zip file.
- Extract the zip file into C:\FMEDemos.
- Open the following readme file and follow the directions inside:
- C:\FMEDemos\D007 - Realtime Data Display in Google Earth\Documentation\readme.txt