Xplage

Xplage is a handy software tool that listens on an IP network for UDP datagrams. These datagrams represent the geographical coordinates of the flight path simulated by the X-Plane flight simulator. What Xplage does is transform these coordinates into KML files that Google Earth can use to create cool "moving map" displays.

How Xplage Works

Xplage generates two different KML files over and over again, based on a refresh rate you can set. The first KML file helps Google Earth show an overhead map with North at the top, placing an icon in the center to mark where the simulated aircraft is located.

Overhead View

In this overhead view, it's like Google Earth’s "eye" is fixed right above the airplane. Every time it refreshes, it shifts the map to keep that icon centered as the plane flies along its path.

Perspective View

The second KML file offers a perspective view of what’s ahead of the aircraft. Here, think of it as if you’re looking out from right in front of the airplane but slightly downward. Each refresh updates this view based on how the simulated aircraft rolls and pitches.

Understanding Refresh Rates

Keep in mind that since Google Earth's refresh rates and those of Xplage don’t sync perfectly, there’s a bit of lag in those moving maps. They actually show images from just before they’re displayed. For example, if you set Xplage to refresh every second and Google Earth every two seconds, you might see up to three seconds of lag behind where your plane really is.

Other Factors Affecting Lag

The delays can also be caused by how quickly satellite imagery loads from Google's servers online. So, while using Xplage isn’t super complicated once you get its structure down, it does have some technical parts to grasp.

Setting Up Xplage

When you run Xplage, it looks at its command line options and sets up a UDP socket to catch incoming data from the simulator. Then it launches three lightweight child processes that wait for either incoming data from X-Plane or for your commands to update KML files or exit gracefully when you want out.

Wrap Up Your Flight with Ease

If you're interested in downloading Xplage, check out this link!