3D GIS
The world is not flat and you are no longer limited to abstraction. Use 3D to see your data in its true perspective, to make better decisions, and to communicate your ideas more effectively and efficiently. ArcGIS Desktop leads the way in 3D GIS.
Alaska Revealed
Exciting news from the Arctic! Version 2 of the Arctic DEM has been released. Topographic elevation of the Arctic can now be viewed and analyzed like never before. This release extends the detailed 2 meter Alaska elevation data with additional 2m data for Novaya Zemlya and Franz Josef Land, as well as preliminary 8 meter data for the entire Arctic. Additional detailed 2 meter elevation data will be released in quarterly installments over 2017 until the arctic data is complete. This is the result of a partnership between Esri, the National Geospatial Intelligence Agency, the National Science Foundation, and the Polar Geospatial Center at the University of Minnesota.
In September 2016, the White House hosted an Arctic Ministerial meeting, with over 20 countries represented, where this data was showcased and new commitments on data provisions were sought. The goal of the meeting and the function of the new data is to help people better understand, adapt to, and address the changing conditions in the Arctic.
The four key themes include:
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Understanding Arctic-Science Challenges and their Regional and Global Implications.
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Strengthening and Integrating Arctic Observations and Data Sharing.
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Applying Expanded Scientific Understanding of the Arctic to Build Regional Resilience and Shape Global Responses.
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Using Arctic Science as a Vehicle for Science, Technology, Engineering, and Math (STEM) Education and Citizen Empowerment.
To access the data, start with the NGA Arctic Support story map here and spend time on the ‘Arctic Digital Elevation Model (ArcticDEM) tab. The embedded apps provide interactive access to the elevation. The data is described in an article here from Medium.com and an article from National Geographic here. This story map illustrates the visualizations that can be generated with the click of the mouse for any user selected area, and a swipe story map explains the background on Digital Elevation Models and compares the new elevation data to the older elevation data by providing the ability to swipe between the maps. The DEMs have been computed from high resolution stereo Digital Globe satellite imagery.
The DEM Explorer is a web app that allows the data user to zoom to any area and review different visualizations such as hillshade, slope, aspect, contours. As the data is temporal in many areas, users can see how the data is changing over time and summarize elevation change for a selected area. The Change Viewer is a simpler app that allows a user to click a point and graphically view the historical elevation of that location. Access to these services is also available in a wide range of applications through the Arctic DEM Group in ArcGIS Online. Most of the apps use the polar projections to reduce distortions which would become severe in generic mapping applications. Finally, a video tour of the story map highlights many of the above products and services.
Quite a bit of publicity and press surrounds these data sets, but all of it is good news. Don’t let the flood of information prevent you from taking the time to investigate these resources and spend some time exploring the Arctic. The actual data is accessible through the web services, and will be of great benefit for anyone doing research in the Arctic, as the map below should make very clear.
Important 3D Terminology
Getting the z-terminology straight
Maps and Scenes
GIS content can be displayed in 2D or 3D views, and there are a lot of similarities between the two modes. For example, both contain GIS layers, both have spatial references, and both support GIS operations such as selection, analysis, and editing.
However, there are also many differences. At the layer level, telephone poles might be shown in 2D as brown circles, while the same content in 3D could be shown as volumetric models—complete with cross members and even wires—that have been sized and rotated into place. At the scene level, there are properties that wouldn’t make sense in 2D, such as the need for a ground surface mesh, the existence of an illumination source, and atmospheric effects such as fog.
In ArcGIS, we refer to 2D as “maps” and 3D as “scenes.”
Local and Global
3D content can be displayed within two different scene environments—a global world and a local (or plane) world. Global views are currently the more prevalent view type, where 3D content is displayed in a global coordinate system shown in the form of a sphere. A global canvas is well suited for data that extends across large distances and where curvature of the earth must be accounted for, like global airline traffic paths or shipping lanes.
Local views are like self-contained fishtanks, where scenes have a fixed extent in which you work. They are better suited for small-extent data, such as a college campus or a mine site, and bring the additional benefit of supporting display in projected coordinate systems. Local views can also be very effective for scientific data display, where the relative size of features is a more important display requirement than the physical location of the content on a spheroid.
Surfaces
A surface is like a piece of skin pulled tight against the earth. Surface data by definition includes an x, y, and z value for any point on it. A surface can be a physical thing that exists in the real world, like a mountain range, or it can be an imagined surface that might exist in the future, such as a road grading plan. It can even show a theme that only exists conceptually, such as a population density surface. Surfaces come in a wide variety of accuracies, with anything from high-resolution, 1-inch accuracy all the way down to a low-resolution surface with 90 meters or coarser accuracy.
Surfaces are fundamental building blocks for nearly every scene you will create because they provide a foundation upon which other content can be draped. Sometimes the surface itself is the star of the show (like a scene of Mt. Everest). Other times the surface serves a more humble role of accommodating other crucial scene data, such as aerial imagery or administrative boundaries. And surfaces can also provide base-height information for 3D vector symbols, like trees, buildings, and fire hydrants, that might otherwise not “know” their vertical position within the scene.
Real Size and Screen Size
Symbolizing features using a real-world size is extremely common in 3D. For example, it’s expected that buildings, trees, and light poles would all be displayed at the same relative size in the virtual world as they exist in reality. Even some thematic symbols, like a sphere showing the estimated illumination distance of one of the light poles, will help communicate the notion of a real-world size.
However, it is also useful to have symbols in the scene that use an on-screen size instead. That is, as you zoom in and out within the view, the symbol always displays with the same number of pixels on the screen. This effect is analogous to a 2D map layer whose symbol sizes do not change as you move between map scales.
Gain a new perspective by visualizing your information in 3D. Use 3D GIS capabilities to address problems that simply cannot be addressed in a 2D context.
Our World Is 3D
Visualize Your Data in 3D for Better Understanding
Evaluate the visual impact of proposed buildings on the wider cityscape or assess the visibility and safety of flight paths. Investigate the relationships between 3D features above and below the ground.
Conduct 3D Analysis to Get the Right Answers
We live in a 3D world and many spatial questions can only be answered in 3D. ArcGIS 3D Analyst comes with true 3D analysis tools that can help you determine the contour, slope, or elevation of a region; the size of the shadow cast by a proposed building; or the geology beneath the surface of an area.
3D-Enable Your Geographic Data for the Complete Picture
Quickly generate 3D master plans, and publish and share your 3D scenes with your organization or the public. You can communicate your ideas more effectively in 3D.
Share Your Work on the Web
Use ArcGIS 3D Analyst for Server to share your 3D Analyst tools and models on desktop, mobile, and web applications.
ArcGIS 3D Analyst for Server is included only with ArcGIS Enterprise Advanced.