We see the world in 3D. With 3D Web GIS, you bring an extra dimension into the picture. You can see your data in its true perspective in remarkable photorealistic detail or use 3D symbols to communicate quantitative data in imaginative ways.
How 3D Mapping Evolved
Geographic information has long been authored and presented in the form of two-dimensional maps on the best available flat surface of the given era—scrawled in the dirt or on animal skins and cave walls; hand-drawn on parchment and, later, onto paper; and now displayed on computer screens. Regardless of the delivery system, the result has been a consistently flat representation of the world. These 2D maps were (and still are) quite useful for many purposes, such as finding your way in an unfamiliar city or determining legal boundaries, but they’re restricted to a top-down view of the world.
Three-dimensional depictions of geographic data have been around for centuries. Using artistic bird’s-eye views found popularity as a way to map cities and small-extent landscapes that regular people could intuitively understand. But because these maps were static and could not be used directly for measurement or analysis, they were often considered mere confections, or novelties, by serious cartographers, not a means of delivering authoritative content.
However, this has no longer been the case since Esri introduced the concept of a scene, which is more than just a 3D map. In a scene, you can also control things like lighting, camera tilt, and angle of view. The mapmaker can craft a scene that creates a highly realistic representation of geographic information in three dimensions, which provides a new way for the audience to interact with geographic content. Spatial information that is inherently 3D, such as the topography of the landscape, the built world, and even subsurface geology, can now be displayed not only intuitively and visually but also quantifiably and measurably so that you can do real analysis and hard science using 3D data.
Advantages of 3D
The most obvious advantage of using a scene is its ability to incorporate vertical (and thus volumetric) information—the surface elevation of mountains, the surrounding landscape, the shapes of buildings, or the flight paths of jetliners. It’s the power of the z-coordinate.
In 3D GIS, the extra dimension enables you to include readily recognized symbols to make your maps more intuitive. You can see the information in situ all viewpoints. Every symbol that you recognize on a map saves you the effort of referring to the legend to make sure you understand what the map shows.
Showing Real-World, Bird’s-Eye Views
Many of the earliest maps, particularly of cities and smaller human habitations, were portrayed as scenes. These stylized maps were created as static 3D bird’s-eye views and were successful in providing understanding of a place. Today’s GIS software users can interact with and see these scenes from many perspectives.
In 3D, you can view of the world more closely to how people typically see it, rather than from directly overhead. With data presented from this approachable perspective, you intuitively understand the size and relative positions of objects as you wander virtually through the scene. There’s no need to explain that you’re in a forest or that a lake is blocking your route—the 3D perspective immediately makes the features recognizable.
This article was excerpted from The ArcGIS Book: 10 Big Ideas about Applying The Science of Where, Second Edition by Christian Harder and Clint Brown. The twin goals of this book are to open your eyes to what is now possible with Web GIS, and then to spur you into action by putting the technology and data resources in your hands. The book is available through Amazon.com and other booksellers. It is also available at TheArcGISBook.com for free.