This post discusses a sample I put together to allow geospatial telemetry data to be visualised using Virtual Earth. The data itself was collected by driving an Aston Martin DB8 Vantage around a track with a GPS receiver. In addition to the location of the car, basic engine telemetry was captured and synchronised with the position data.
The basic idea was to take the data, and "play back" the drive of the car around the track, layering information on a map such as vehicle position, speed, braking position etc. Multiple data sets can be overlaid on the map for comparison. In order to show the vehicle position, a basic 3D car model was chosen. Virtual Earth supports both 2D and 3D map views, the latter of which gave an opportunity to implement a "virtual helicopter" camera which could follow the vehicle around the track.
This video shows a couple of laps of telemetry data. The path taken on each lap is drawn on the map (each in a different colour), and each has its own 3D car model (labeled "A" and "B" respectively). The buttons along the bottom of the screen control the "virtual helicopter" camera position and which car the camera is pointing at, and can be seen in more detail in Figure 1 below.
Figure 1. "Virtual Helicopter" Camera Positions
Front/Rear
These angles follow the car a short distance above and in front of/behind respectively.
Above/Blimp
This angle is directly above the car at a low/high altitude respectively.
Fixed
This setting fixes the camera at its current point in space, but points to the selected car.
In Car
This setting sets the camera position to be "inside" the car, and points the camera in the direction that the car is traveling.
Free
This setting allows the user to freely move the camera.
As an aside, during development of this sample I initially only had access to a couple of models in .x format. Until I managed to find a suitable model for the car, I had to use the following:
Figure 2. Initial Actors
Initially it was helpful to add some axes to the models so I could ensure they were oriented correctly - you can see these in Figure 2. I also experimented with transparency for "ghosting" the model(s) which didn't have focus:
Figure 3. Ghost Actor(s)
The cube shown in Figure 3 was used as a visual marker (also with axes) to show the camera position when I was in a "Free" camera mode. This was really helpful in ensuring the camera was positioned and tracking objects correctly.
