Let’s begin with a poll. With a show of hands, how many of you currently work with some sort of 3D data in Global Mapper?* One, two, three, four… OK, I think I can safely conclude that everyone’s hand is raised, just as I thought. We are currently at a significant epoch in the history of mapping. Traditional cartographic renderings consider the Earth from a two-dimensional, birds-eye perspective but that is rapidly changing. Our world is a 3D world and the technologies that we use to visualize, analyze, and distributize** our geospatial data are increasingly taking the additional dimension into consideration.
Case in point is Global Mapper’s ingenious fly-through recording capability. What better way to show your client the scope of your engineering project, or to share the archeological model created using the Pixels-to-Points tool, or to simply soar over mountains and valleys unencumbered with the constraints of gravity, feeling the wind in your face as you glide… OK settle down. Back on task.
As is typical with Global Mapper, the fly-through recording functionality is remarkably straightforward. Draw a line defining the flight path, enter the flight parameters, open the 3D View, click the Play button and you’re on your way (with seatbelts fastened and tray tables in their upright and locked position, of course). Alternatively, if you have a prerecorded track file, such as one that was created by a drone, you can use that as the flight line. All of the flight parameters such as speed, height, etc., will be automatically assigned.
Let’s take a look at an actual example.
1. Load a 3D data layer in Global Mapper
In this scenario, we’ll use a 3D mesh created in the Pixels-to-Points tool. Frequent viewers of Global Mapper video presentations or training class attendees will already be familiar with the data in question ̶ the famous Brazilian landfill.
2. Draw the flight path
Before putting pen to paper (or digitizer to screen, to be more precise), we will need to consider what form our flight will take. There are three alternatives: Straight Ahead, in which the view will look in the direction of the flight (a cockpit view, if you like); Fixed Direction, in which the view will always be on a specified bearing or azimuth; or Fixed Point, in which the view will always be focused on a target point in three-dimensional space. Because we will be using the latter, we will create a line that encircles the focus point.
3. Set the flight parameters
With the newly created line selected on the map, we click the Create 3D Fly-through button (hint: it looks like an airplane, you can’t miss it). If you haven’t seen it before, the dialog box includes a table listing the XY coordinates of each vertex in the line along with a number of additional columns that will be automatically filled in after we apply the necessary settings.
As previously noted, we’re going to use the Fixed Point option, which requires us to enter the focal target, a process made easy using the Select from Map button. Because we want the perspective to be looking down rather than horizontally, we establish a target Z value corresponding with ground elevation or a little below, let’s say 550 meters.
Elevation Mode in this case will be Absolute, meaning that our flight will maintain a specific altitude. The alternative, Relative to Ground, will result in the simulated flight rising and falling while maintaining a consistent height about the surface (the captain apologizes for the turbulence). For our landfill flight, we will be cruising at a consistent altitude of 650 meters.
Finally, we need to decide how fast we want to fly. This can be established by either setting the duration of the flight or by entering an actual meters-per-second value. Setting one of these variables will automatically change the other. Our circuit of the landfill will take 40 seconds.
Clicking the Generate Fly-through Data button will populate the aforementioned table with per-vertex flight details and double-clicking on any line in the table will offer the option of editing the settings for that segment. After clicking the OK button, we’re ready to take to the air.
4. Play the fly-through
Now for the fun part. In the 3D View, a collection of buttons controls the preview, playback, and editing of the flight. Click Play and away we go. In the corresponding 2D view, we can monitor our progress and heading along the flight line. Should we need to make any changes, there’s an identical airplane button in the 3D View, which opens the same dialog box that we used to create our flight.
5. Export the video
Finally, we click the button that resembles a vintage movie camera to save a video file in either MPEG-4 or AVI format with options for defining the resolution and frame rate. The video can then be posted to our favorite movie sharing site or sent directly to a client.
Wasn’t that easy? Time to try it for yourself.
*If you actually did raise your hand in response to reading this question you might want to explain to your office colleagues what you were doing
**Not a real word