Map Venice in 3D

Venice is a famously low-lying city that is frequently affected by flooding. Acqua alta, which means high water in Italian, is the seasonal high floodwaters that can impede daily transportation needs and threaten Venice's historic architecture.

In this tutorial, you'll visualize Venice's low elevation by mapping the city in 3D. First, you'll add a layer of elevation to a 2D map. Then, you'll convert the data into 3D. This tutorial will teach you basic 3D workflows in ArcGIS Pro, including adding an elevation source to a scene, displaying symbols in 3D, and extruding building footprints.

This tutorial was last tested on July 31, 2024, using ArcGIS Pro 3.3. If you're using a different version of ArcGIS Pro, you may encounter different functionality and results.

Requirements

• ArcGIS Pro (see options for software access)

Map Venice in 3D

Add raster data

If you've ever created a 2D map, you're probably familiar with feature data: data displayed as discrete objects, or features. While feature data is great for depicting things like structures, canals, or landmarks, it's not the best way to depict elevation over a continuous surface. For that, you'll use a different type of data, called raster data.

Raster data is composed of many pixels, each with its own value. Although it looks different from feature data, you add it to the map in the same way. First, you'll open a project showing a 2D map of Venice, complete with feature data. Then, you'll add a raster layer showing elevation to the map.

1. If you completed the previous tutorial in this series, Map Venice in 2D, open the Venice project you created in ArcGIS Pro.
2. If you did not complete the previous tutorial, download the Map Venice in 3D project package. Locate the downloaded project package and double-click it to open it in ArcGIS Pro. If prompted, sign in using your ArcGIS account.

   Note:

   If you don't have access to ArcGIS Pro or an ArcGIS organizational account, see options for software access.

   Whether you're using the project you created in the previous tutorial or downloaded the project package, your project includes a map showing Venice's structures, canals, and landmarks.

   

   Next, you'll add the elevation data.

3. On the ribbon, click the Map tab. In the Layer group, click the Add Data button.

   

   The Add Data window appears.

   Note:

   If you're using ArcGIS Enterprise, download and unzip Venice_Data.zip to the project folder you created with the project. Browse to Venice_Data and add the Venice_Elevation_Data item. For portal security, Enterprise doesn't allow users to search for items stored in ArcGIS Online. Data must be hosted in your licensing portal, ArcGIS Living Atlas, or locally.

4. In the Add Data window, under Portal, click ArcGIS Online.
5. In the search box, type Venice_Elevation_Data owner:Learn_ArcGIS and press Enter.

   

6. Double-click Venice_Elevation_Data to add it to the map.

   Note:

   The package is 150 MB and may take several minutes to download, depending on your network connection.

   The package contains two layers: Venice 1m and Venice Ground Surface.

7. In the Contents pane, uncheck the boxes next to Landmarks, Canals, and Structures, leaving only Venice 1m and the basemap visible.

   

   This layer is a raster layer. In a raster layer, each pixel stores its own value. The name of the layer, Venice 1m, refers to its resolution: the size of its pixels. The 1m means that each pixel represents an area of one square meter.

   This raster layer was made by interpolating a series of points. Because it's an interpolation, there may be some inaccuracies, so this raster layer would not be suitable for real-world analysis. For the purposes of this tutorial, however, it'll suit your needs.

8. In the Contents pane, click the arrow next to Venice 1m to view its symbology.

   

   Instead of a single symbol, this layer has a color scheme for different values. The values represent elevation in meters. Venice's elevation ranges from just below sea level (dark) to about 11 meters above sea level (light)—very flat terrain.

9. On the map, click anywhere on the raster layer.

   A pop-up appears for the pixel you clicked. In the example image, the pixel has an elevation of about 1.04 meters above sea level.

   

10. Close the pop-up.

    From examining the map, you may conclude that most of Venice lies only about 1 meter above sea level, with the eastern and western ends of the city at a somewhat higher elevation. Such a low-lying environment leaves Venice susceptible to flooding. To better understand Venice's extremely flat terrain, you'll visualize it in 3D.

Convert a map to a scene

Traditionally, a map displays data in 2D. A scene is a map that displays data in 3D. By default, ArcGIS Pro will convert a map to a global scene, which depicts the entire world as a spherical globe. Since your area of interest is Venice, not the entire globe, you'll alter the settings so the map converts to a local scene instead.

1. On the ribbon, click the View tab. In the View group, click Convert and choose To Local Scene.

   

   Your map converts to 3D, creating a view called Map_3D. You can return to your 2D map at any time by clicking the Map view tab.

2. In the Contents pane, uncheck Venice 1m to turn it off. Check Landmarks, Canals, and Structures to turn them on.

   

   In scenes, layers are designated as either 3D or 2D. Currently, your layers are 2D layers, which is part of the reason why they are still flat. You'll change this later in the tutorial.

3. Navigate the 3D scene by pressing V while dragging the pointer to tilt and rotate the scene. Pan and zoom the same way you would in a 2D map. You can also zoom by right-clicking.

   

   The flatness of Venice's terrain contrasts with the hills in the distance. Since your raster layers do not extend past Venice, where did those hills come from? By default, scenes use a map of elevation data, called an elevation surface, to determine the ground's elevation. This default surface spans the entire world, although at a low resolution (meaning low detail).

4. On the ribbon, click the Map tab. In the Navigate group, click Bookmarks and choose Venice.

   Note:

   When you converted your map to a scene, you also converted your map's 2D bookmarks to 3D bookmarks. Both sets of bookmarks are currently identical, so you can use either.

Add an elevation source

For visualization purposes, the default ground surface accurately depicts Venice as incredibly flat. However, its low resolution makes it lacking in detail. You'll add one of your high-resolution raster layers as a new elevation surface.

1. In the Contents pane, check the Venice Ground Surface layer to turn it on.

   

   The Venice Ground Surface layer has similar elevation data to the Venice 1m layer but includes sea level elevation data for some of the surrounding lagoon. The extra data provides context to Venice's elevation and helps set the scene. You'll use this layer as your ground elevation.

2. In the Contents pane, right-click Venice Ground Surface, point to Elevation, and choose Duplicate in Ground.

   

   The venicesource layer is added to the Contents pane under the Elevation Surfaces section. There are two elevation sources. The first is the venicesource layer you just added, and the second is the default surface.

   The new elevation source is set as the ground in the area around Venice. The default elevation values are still used in the area outside Venice, so you can still see the hills in the background.

3. In the Contents pane, under 2D Layers, uncheck Venice Ground Surface to turn it off.
4. Pan, zoom, and tilt to navigate the scene and better view the new ground elevation.

   

   You may have to zoom very close to see the shifts in elevation—Venice is incredibly flat and low-lying. The dramatic lack of elevation puts into perspective how serious flooding can be in Venice.

5. When finished, navigate to the Venice bookmark.

Display features in 3D

As you saw when you tilted the scene, the Landmarks layer is displayed as a 2D layer, with its push pin symbol flat on the ground. While this layer does not have elevation data, you can give depth to the push pin symbol by changing how the layer is displayed.

1. In the Contents pane, under 2D Layers, drag the Landmarks layer from the 2D Layers section to the 3D Layers section.

   

   The push pins appear in 3D, standing upright as you rotate and pan the map.

   

   Another layer that is currently flat but could be displayed in 3D is the Structures layer. Unlike the Landmarks layer, the Structures layer has height data in its attributes. To display the layer in 3D, you'll use extrusion, which displays features in 3D using a constant or an attribute as the z-value.

2. In the Contents pane, drag the Structures layer from the 2D Layers section to the 3D Layers section, placing it under the Landmarks layer.

   The appearance of the Structures layer changes slightly, but it's still flat. To extrude the features, you'll use an attribute to determine each feature's z-value.

3. In the Contents pane, right-click Structures and choose Attribute Table.

   The table has five fields, one of which is Height. You'll extrude the Structures layer with the values in this field.

   

4. Close the attribute table.
5. On the Feature Layer tab, in the Extrusion group, click the Type button and choose Max Height.

   Note:

   The Feature Layer tab is contextual, meaning it only displays under certain circumstances. This tab only appears if a layer is selected in the Contents pane. Make sure the Structures layer is selected before proceeding.

   

6. In the Extrusion group, for Field, choose Height. Confirm the Unit parameter is set to Meters.

   

   The features are extruded, meaning they are given a height value based on the selected field. They now appear 3D on the map.

   

7. Explore the scene. When finished, navigate back to the Venice bookmark.
8. Save the project.

You've converted your 2D map into a scene and adjusted elevation and rendering settings to display your data more effectively. From your observations, Venice is incredibly low-lying and flat, placing it in danger of even small increases in water level.

In this tutorial, you learned many basic workflows involving 3D in ArcGIS Pro. You can apply these workflows to other locations and explore the world in 3D.

You can find more tutorials in the tutorial gallery.

Acknowledgements

• The Structures, Canals, Landmarks, Venice 1m, and Venice Ground Surface layers were acquired from or derived from data acquired from Comune di Venezia - Portale dei servizi. The data is shared under the Italian Open Data License 2.0 (IODL-2.0), which allows for free copying and distributing of the data, as well as the creation of derivative works.
• Topographic map sources: Esri, HERE, Garmin, FAO, NOAA, USGS, Intermap, METI, OpenStreetMap contributors, and the GIS User Community