Build a 3D cityscape by themes

3D scenes can represent features based on their state or condition and are categorized into a theme. These layers are listed in the 3D Layers group of the Contents pane, much like realistic vector content. However, they can be modified to show more than just representation of the real.

Thematic 3D vector symbology may use real-world units, such as meters or feet, or use the traditional cartographic unit of points representing size on screen. Much like realistic features, thematic 3D features can obtain their base elevations from a surface, stored shape z-values, feature attributes, or from a constant value. However, the base elevation of a thematic feature is another visual representation that can be altered to represent a state or condition.

In this exercise, you will be working with simple GIS data for a city–building multipatches, parcel footprints, water main lines, city-managed tree points, and regularly spaced wind sample points to create a thematic representation of different aspects of the city. In this tutorial, you will use color to represent 3D objects as a theme, match thematic representation across multiple layers, and use thematic extrusion, size, shape, and orientation on 3D layers.

This tutorial was last tested on February 1, 2024, using ArcGIS Pro 3.2. 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)

Apply 2D and 3D symbology

To start, you will download the data files and open the layers in ArcGIS Pro. Then you will explore the scene and configure the symbology for 2D and 3D layers thematically.

Download and open the project

First, download the data.

1. Download the ThematicCityscape.zip compressed folder.
2. Locate the downloaded file on your computer and extract it to a location you can easily find, such as your Documents folder.
3. Open the ThematicCityscape folder. Notice that the folder contains several layer package files you will be using in the tutorial steps.

   The data represents an area in San Diego, California, and comprises 3D geometry and texture maps, along with points, 2D polygons, 3D polygons, elevation data, and other data delivered in various formats. The approximate coverage of the 3D model is 19.5 square kilometers.

4. Start ArcGIS Pro. Under Blank Templates, click Local Scene.

   

   Note:

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

5. In the Create a New Project window, for Name, type ThematicCityscapeProject and click OK.

Apply symbology on layers

One of the simpler methods for doing thematic representation of a 3D object is varying its color. This is very similar to choropleth mapping in 2D. You can vary the color of a feature based on unique categories or ranges of values. In this case, you have a set of buildings for an area of interest that you want to represent based on the number of floors in each building.

Before you can apply symbology, you need to add the layer to your new blank scene.

Note:

In the project folder you downloaded, layers with Completed in its name already has the steps in this tutorial applied and should be used for reference after completing the work.

1. On the ribbon, click the View tab. In the Windows group, click Catalog Pane.

   

   The Catalog pane appears.

2. In the Catalog pane, right-click Folders and click Add Folder Connection.
3. In the Add Folder Connection window, browse to the ThematicCityscape folder containing the layer packages (.lpkx files) and click OK.

   The ThematicCityscape folder adds to the Catalog pane.

   

4. In the Catalog pane, expand the folder ThematicCityscape folder, and drag the Untextured Buildings – Source.lpkx layer package to your 3D scene.

   The layer appears on the 3D Layers section of the Contents pane. Multipatch layers always appear here by default, since they are inherently z-enabled.

5. Right-click the Untextured Buildings (AOI) layer and select Zoom To Layer.

   

6. At the bottom of the scene, click the Show full control button in the Navigation tool.

   

   The Navigation tool expands.

7. Use your mouse wheel button to zoom in closer to the buildings and use the Navigation tool to explore the scene.

   

   The default color applied here makes the buildings hard to see against the default basemap.

8. If necessary, ensure the Untextured Buildings (AOI) layer is selected in the Contents pane.
9. On the Feature Layer tab, in the Drawing group, click Symbology.

   

10. In the Symbology pane, for Primary symbology, choose Graduated Colors.

    

    By default, the Graduated Colors renderer finds the first field in your data that could be meaningful for a Graduated Colors renderer, in this case, FloorCount. It then applies some default settings to the method of graduation, number of classes, and picks a random color scheme. You will update the symbology.

11. In the Symbology pane, for Classes, choose 7.

    It is often best to keep the number of classes to seven colors. Once you go beyond this threshold, creating color schemes that can effectively show more classes becomes challenging. Consider your audience when choosing how many classes you are going to use.

12. In the Symbology pane, using the Color scheme drop-down menu, check the Show names check box and choose Blues (Continuous).

    

    The scene updates to display buildings with a graduated white-to-blue color representing floor count. Taller buildings with more floors are darker and lower buildings are lighter.

    

13. Click the Color scheme drop-down menu and click Format color scheme.

    

    The Color Scheme Editor window appears, which allows you to define different color ramps for application as graduated symbols. You can add or remove colors to influence the appearance of the ramp and alter transparency at different intervals along the color ramp.

    Next, you will modify the color ramp to show buildings from beige to brown, with representing buildings with fewer floors and brown for buildings with more floors. You'll also format the shorter buildings to display more transparent than taller buildings.

14. Click a color in the middle of the color scheme and click the Remove color button.

    

15. Repeat this until you are left with one color on each end of the color scheme.

    

16. Click the color on the left, and for Color, choose Sahara Sand. For Transparency, type 20.

    Tip:

    To see the name of a color, point to the color.

    

17. Click the color on the right. For Color, choose Burnt Umber, and for Transparency, type 40.

    

18. Click OK.

    The scene updates to display the new transparent buildings in hues of brown.

    

19. On the Quick Access Toolbar, click Save to save your project.

    Tip:

    You can also save your project by pressing Ctrl+S.

You now have a set of buildings, displayed thematically by the numbers of floors from beige to brown. Note, you ramped from a light color to a dark color going from a small number of floors to large number of floors but inverted that for transparency, making darker colors more transparent and lighter colors less transparent. This reduces how stark dark colors appear in the scene. Excessive transparency on lighter colored features tends to make them fade drastically from visual prominence.

Match 2D and 3D themes

Sometimes you want to match thematic representation across multiple layers, where some of those layers may be 2D and others 3D.

You have a set of proposed buildings for this city, created using ArcGIS CityEngine. You want to understand their impact on solar radiation in the urban environment, but you want to understand the impact both on the surface of the earth and on the rooftops of the existing buildings. You want to display solar radiation on the ground and on the buildings using similar symbology so that the two layers blend into a seamless visual representation.

Let’s start by adding some additional data to your scene.

1. In the Catalog pane, drag the Proposed Buildings.lpkx layer package onto your 3D scene.

   Tip:

   To open the Catalog pane, on the ribbon, click View, and in the Windows group, click Catalog Pane.

   

   These are procedurally generated proposed buildings for the city. The buildings are thematically colored based on their use type per floor. The colors were applied as multipatch textures, so they cannot be changed or modified using the Symbology pane.

2. In the Catalog pane, drag the Solar Radiation (AFTER).lpkx layer package into your 3D scene.
3. In the Contents pane, check and select the Solar Radiation (AFTER) layer.

   

   This layer represents kilowatt hours of solar exposure. It was created by combining the building forms with an elevation surface and running a geoprocessing tool to assess solar radiation.

4. Drag the Building Solar Potential - Source.lpkx layer package into your 3D scene.

   

   Here, procedural technology was used to pull out the roofs of all the buildings in the area of interest. Roofs were split into panels, so each part of the roof could carry a different value. Then a spatial join was used to attach solar radiation values from the raster to each of the roof panels.

5. On the Contents pane, click the BuildingPanelsSolar layer and, if necessary, open the Symbology pane.
6. In the Symbology pane, for Primary symbology, choose Unclassed Colors.
7. For Field, choose Solar.

   

8. For Color Scheme, click the drop-down menu and click Format Color Scheme.
9. In the Color Scheme Editor window, set the following parameters:

   • Remove all the color stops except the first and last color.
   • Click the left color and for Color, choose Yucca Yellow.
   • Click the right color and for Color, choose Mars Red.

   

10. Click OK.

    The BuildingPanelsSolar layer updates to display roofs symbolized by the Solar value assigned to each roof panel.

    

    Displaying multiple thematic layers simultaneously can be confusing visually because of color conflict.

11. In the Contents pane, click the symbol for the Untextured Buildings (AOI) layer. In the Symbology pane, for Primary symbology, choose Single Symbol.
12. For Symbol, right-click the symbol and choose a medium gray color.

    

    Now the solar potential roofs are more visible.

    

13. Save your project.

You now have a map that displays analytics across multiple layers. By thematically representing the same data on the buildings, you can blend the 2D analytic results with your 3D data.

Apply thematic extrusion

Extrusion is another way to represent a condition, status, or intensity of a feature. It can be an abstract representation, such as driving extrusion height based on a ratio to the financial value of a parcel normalized by its area. Or it can be concrete, relating the extrusion height to regulatory limit on the maximum height in a zoning district. In both cases, the data represented is thematic, meaning it does not exist in the physical world as an object but has meaning in 3D space.

Explore and apply thematic extrusion

In this section, you will explore an example of thematic extrusion. The city has identified a subset of its parcels that are ideal for redevelopment. They parallel a proposed bus rapid transit route through the city. The city is considering altering a planning policy for the floor area ratio (a measure of density) for parcels along a rapid transit route to increase urban density. They are also considering increasing the maximum height allowed for buildings along the route. They have developed a layer representing this development potential and want you to display it in 3D.

1. In the Contents pane, turn off all 3D and 2D layers in your scene, except your basemap.

   Tip:

   You can press Ctrl and uncheck one layer to uncheck all the layers at the same time.

2. In the Catalog pane, in the ThematicCityscape folder, drag the Development Potential - Source.lpkx layer package onto your 3D scene.

   

   The layer displays as a set of 2D polygons draped to the ground. It already has thematic representation for its floor area ratio (FAR) applied as a part of its symbology. However, you need to represent the maximum building height as well.

3. In the Contents pane, drag the Development Potential layer into the 3D Layers category.

   

   

   The layer updates. The layer appears uneven because the vertices of each polygon are being placed on the uneven surface, and their interiors are being calculated unevenly across it. Next, you will extrude the Development Potential layer and apply a cartographic offset.

4. If necessary, in the Contents pane, click the Development Potential layer to select it.
5. Click the Feature Layer tab, and in the Extrusion group, click the Type drop-down arrow and choose Min Height.

   

6. In the Extrusion group, click the Extrusion Expression button.

   

   The Expression Builder window appears. Next, you will create an expression that will extrude each polygon by adding 10 to its current height value.

7. In the Expression Builder window, in the Fields list, double-click height, and type + 10.

   Your expression should read as follows: $feature.height + 10.

   

8. Click OK.

   The Development Potential layer updates to displaying buildings where extrusion height is the value in the Height field plus 10.

   

9. Zoom in close to one of the buildings and notice the symbology effect at the base of the polygon.

   

10. In the Contents pane, right-click the Development Potential layer and select Properties.
11. In the Layer Properties window, click the Elevation tab. For Cartographic offset, type -10. Ensure Elevation units is set to Meters.
12. Click OK.

    The base of each parcel is now below the surface by 10 meters and the uneven building footprint is no longer visible.

    

    You extruded by the minimum height limit plus 10 meters. Then you used a cartographic offset to slide the base of each parcel below the surface by 10 meters. This removed any visual conflict with the surface and gave us nice, clean edges around the development polygons. You also used the minimum elevation value for each polygon to extrude from, thereby representing the worst-case development constraints.

13. Save your project.

    The fill color is not the only thing you can change on an extruded polygon. You can also apply thematic mapping on the edges of the extruded forms, along with polygons and multipatches.

14. In the Catalog pane, drag the Development Potential - Overlay.lpkx and Development Potential - Underlay.lpkx layer packages onto your 3D scene.

    Two new layers are added to the scene that show the land use category for each of the proposed redevelopment parcels.

    

    The overlay color codes the edges of each extruded polygon based on the land use. The underlay colors the parcel as draped to the ground by the land use category.

    There are now three layers in the Contents pane named Development Potential. Two are listed under 3D Layers, one that shows edge effects and one that shows the building shapes as translucent, 3D shapes and shows the edge effects in 3D space.

15. For the Development Potential layer you just added, click the name twice to edit it. Type Development Potential Overlay and press Enter.

    

    Note:

    The underlaying Development Potential layer is under the 2D Layers group in the Contents pane because it has no elevation information associated with the features. Optionally, you can rename this layer as Development Potential Underlay.

    In the Contents pane, you can see the different edge effects for each land use category.

    You can apply different frame coloring around the polygons, but not all display modes (dashes, for example) will work on polygon edges. In the current scene, you are displaying a combination of three thematic variables, FAR, maximum buildable height, and land use category.

    

    The current view shows a great deal of information and may even be a visual overload. Consider how much information you combine into a scene or set of layers and decide which pieces of information are the most important and receivable for your given audience.

16. Turn off the Development Potential layer.

    Only the Development Potential Overlay and Development Potential layers are visible.

    

    Edge rendering can be helpful in editing workflows for extruded lines, extruded polygons, and multipatches, as it helps highlight the geometry driving the shape of the feature.

17. Save your project.

Apply thematic size and shape symbology

Representing multipatches and polygons differs significantly from how you represent lines and points. For multipatches and polygons, shape is explicitly defined by the geometry (though you can vary the size of edges, which are treated as lines, on both). However, for lines, you can vary the shape of the geometry (also called a profile) that is swept along the length of the line. For points, you can use any number of prebuilt 3D models to create your symbol or import your own models. Varying the size of the swept profile along a line, or the size of a 3D model on a point, can be used to highlight thematic differences in data.

For instance, you can represent the storm water load of a storm water culvert system based on the size (width, height, radius, and so on) of the profile used to represent it. Or you can vary the size of cylinders representing subsurface earthquake epicenters to represent magnitude.

Apply size for thematic representation

In this section, you will explore size as a visual variable. The city's public works department has a dataset that shows its water mains across the city. Public works employees recently began collecting water pressure values at locations along these mains to get a sense of where they might have insufficient pressure to support development needs. They want to visualize the pressure values in 3D, as pipes of varying size.

1. In the Contents pane, uncheck and collapse all the current displayed layers in your scene except your basemap.
2. In the Catalog pane, drag the Water Mains - Source.lpkx layer onto your 3D scene.
3. In the Contents pane, check the Water Mains layer check box to turn the layer on.
4. Right-click the Water Mains layer and click Zoom To Layer.

   

   Next, you will update the symbology by the size of the pipes.

5. In the Contents pane, right-click Water Mains and click Symbology.
6. In the Symbology pane, enter the following:
   • For Primary symbology, choose Graduated Symbols.
   • For Field, choose PSI.
   • Ensure Minimum size is set to 0.5 pt.
   • For Maximum size, type 8 and press Enter.

   Note:

   PSI stands for Pounds per square inch and is a unit of pressure used in many applications.

   

7. Click the symbol for Template.

   

   The Gallery tab appears.

8. Click the Properties tab, and click the Layers tab. Under Appearance, for Color, choose Cretan Blue. For Profile, choose Tube.

   Tip:

   To see a color name, point to the color.

   

9. Click Apply.
10. Use the Navigator or keyboard shortcuts to explore the scene. Zoom in and out and notice how the size of the pipes stays consistent.

    

    The size of the symbols is scaling based on the screen point size. That means even when you zoom in, each pipe will always take up the same amount of screen space. This is useful if you want to guarantee that a feature will always be visible regardless of scale. However, at certain scales, symbols will merge and look less clear.

11. Right-click the Water Mains layer and click Zoom To Layer.
12. In the Contents pane, right-click the Water Mains layer and click Properties.
13. In the Layer Properties window, click the Display tab. Check Display 3D Symbols in real-world units and click OK.

    

14. In the Symbology pane, click the back button. For Minimum size, type 2, and for Maximum size, type 20.

    The symbols are now represented by real-world units. Which means they won't get larger and lump together as you zoom away from them, but they will get smaller, then become pixelated, and fade to the point where they no longer appear.

15. Zoom in and out and notice how the size of the pipes stays the same absolute size.

    

16. Zoom out to the city, to Southern California, to the state level, and to global view.

    As you zoom out, the symbols shrink, become indistinct, and then disappear. Varying the size of the symbols in this case is the only one way you could represent pressure, or PSI.

    Next, you will explore extrusion as another method to represent PSI.

17. Uncheck the Water Mains layer.
18. In the Catalog pane, drag the Water Mains - Extruded.lpkx layer package onto your 3D scene. Right-click the Water Mains layer you just added and click Zoom To Layer.

    

    Much like the graduated symbols, where relative size indicated how much PSI was available, the extrusion height provides the same visual differentiation here.

19. On the Feature Layer tab, in the Extrusion group, click the Expression Builder button and review the expression used to provide the extrusion height.

    The Expression Builder window appears with the expression used to symbolize extrusion height.

    

    The expression reveals that the value for PSI was used to vary the extrusion height for each segment of the Water Main - Extruded layer.

20. In the Expression Builder window, click Cancel and save the project.

Now that you have applied and explored size as a thematic representation in a 3D scene, you will explore how to use shape to represent a theme of information in your 3D scene.

Apply shape for thematic representation

Points can be represented by different kinds of 3D models, markers, and symbols. One way to indicate thematic difference is to vary their shape. Some forms of markers and symbols can be billboarded, so that they always face the viewer. Others can be billboarded, so they rotate around a z-axis to face the viewer.

The city's public works department has been keeping track of the tree conditions around the baseball park, as they represent a critical asset and have high visibility. Some of the surveyed trees have been found to be dead, diseased, or stressed. Public works department employees want to visualize these in a way that calls out clearly which trees must be replaced quickly.

1. In the Contents pane, turn off all the current displayed layers in your scene except your basemap.
2. In the Catalog pane, drag the Trees - Source.lpkx layer onto your 3D scene. Right-click the added layer and click Zoom To Layer.

   Note:

   The symbology of the layer is randomly generated and may differ from the example image, but it does not impact the results of the analysis.

   

   The trees are displayed as single points. You'll change them into 3D trees.

3. On the ribbon, click the Feature Layer tab, and in the Drawing group, click the Symbology drop-down menu and choose Unique Values.

   

   The Symbology pane appears.

4. In the Symbology pane, for Field 1, choose Condition.

   

   The layer symbology updates to show a unique symbol for each Condition type.

5. Under Classes, click the symbol for the Dead.

   

   The Gallery tab appears.

6. Click the Properties tab and next to the symbol, change Shape marker to 3D model marker.

   

7. Click the Gallery tab.
8. Click Project styles and choose All styles. In the search bar, type generic tree and press Enter.

   

9. Under 3D Vegetation - Thematic, choose Generic Dead Tree.

   Tip:

   To see the full name of a style, point to the style.

   The Generic Dead Tree style is designed to cartographically represent any kind of tree and is shaded to allow for further styling.

   The symbol for Dead trees updates to the selected style.

10. In the Symbology pane, click the Properties tab and click the Layers tab.

    

11. Under Appearance, set the following parameters:
    • For Tint model, check the box.
    • For Color, choose a red color.
    • For Height (Z), type 40 and press Enter.

    

12. Expand Position, check the box for Override model origin with a custom anchor point, and for Z, type -50 and press Enter.

    

13. Click Apply.

    The symbology updates on your scene.

    

14. At the top of the Symbology pane, click the back button and click the symbol for Diseased Trees.
15. Change the symbol type from Shape marker to 3D model marker.

    

16. Under Appearance, click Style and search for and double-click the Generic Tree style.
17. In the Symbology pane, set the following parameters:

    • Check Tint model
    • For Color, choose an orange color.
    • For Height (Z), type 25 and press Enter.
    • Under the Position section, for Z, type -50 and press Enter.

18. Click Apply
19. Follow the previous steps to configure the Healthy and Stressed tree styles.

    For Healthy trees, set the following:

    • Change Shape marker to 3D model marker.
    • For Style, choose Generic Tree.
    • Check Tint model and for Color, choose a green color.
    • For Height (Z), type 13.
    • Under Position, for Z, type -50.
    • Click Apply.

    For Stressed trees, set the following:

    • Change Shape marker to 3D model marker.
    • For Style, choose Generic Tree.
    • Check Tint model and for Color, choose a yellow color.
    • For Height (Z), type 18.
    • Under Position, for Z, type -50.
    • Click Apply.

    The scene updates with the color and shape symbology you configured.

    

20. Save your project.

    Optionally, you can further explore changing the 3D models to represent this condition. For example, you can explore other 3D models and select the appropriate tree species.

In this section, you symbolized point symbols into 3D tree models that are styled based on their condition. By styling tree condition with color and size, you have created a visual hierarchy of trees that require further care.

Apply thematic symbology using orientation

Points also can be rotated around their axes. This orientation can represent a variable as well. For instance, you could have a point over each county in the United States that points to the left or to the right depending on which party the residents voted for and by what percentage.

The city has been trying to understand the impact of its proposed development on heat islands in the downtown area. The city has conducted solar radiation analysis previously and recently has done same additional airflow analysis to show where areas of still air might overlap areas of high solar radiation exposure. The city wants to display these air flow points, colored and sized to their intensity and oriented toward their flow direction, combining three methods of thematic visualization into a single layer.

Apply unclassed 3D symbology

To start, you will turn on the building layers and add the layers that show wind speed and direction before and after the proposed buildings are added.

1. In the Contents pane, turn off and collapse all the current displayed layers except the basemap, the Untextured Buildings (AOI), and the Proposed Buildings layers.

   

2. In the Catalog pane, if necessary, expand the Folders and ThematicCityscape folder, and drag the Wind (AFTER) - Source.lpkx layer on your 3D scene.

   The Wind (AFTER) layer is added to your scene.

   

3. Click the Wind (AFTER) layer to select it.
4. On the ribbon, click the Appearance tab, and in the Drawing group, click the Symbology drop-down menu and choose Proportional Symbols.

   The Symbology pane appears.

5. In the Symbology pane, for Field, choose speed_1. For Data represents, choose Unclassed symbols.

   

6. Click the symbol next to Template.

   Note:

   The symbology color of the layer are randomly generated and may differ from the example image, but it does not impact the results of the analysis.

   

   The Symbology Gallery appears.

7. Click the Properties tab, click the Layers tab. Update Shape marker to 3D model marker.

   

8. Under Appearance, click Style.

   

9. In the Choose a 3D model window that appears, double-click the Arrow symbol.

   

10. In the Symbology pane, click Apply.

    The layer symbology updates.

11. At the top of the Symbology pane, click the back button.
12. For Minimum size, type 3, and for Maximum size, type 10.

    

13. At the top of the Symbology pane, click the Vary symbology by attribute tab and expand the Rotation section.

    

14. In the Rotation section, for Direction (Z) choose dir_1 field, and for Rotation style, choose Geographic.

    

15. Expand Color and for Field, choose speed_1. For Color scheme, choose Yellow to Red

    To see a color scheme name, point to the color scheme.

    

    The symbology for the Wind (AFTER) layer is complete. Next, you want to apply the same symbology for the Wind (BEFORE) layer so you can compare the proposed buildings will have on urban canyon effect.

16. In the Catalog pane, drag the Wind (BEFORE) - Source.lpkx layer package onto your 3D scene.
17. Click the Feature Layer tab, and in the Drawing group, click the Import button.

    

    The Import Symbology window appears.

18. In the Import Symbology window, for Symbology Layer, choose Wind (AFTER), and click OK.

    The Wind (BEFORE) layer is updated and now displays the same symbology as the Wind (AFTER) layer.

19. Save your project.

Review the proposed plan

Next you will turn the Wind (BEFORE) and Wind (AFTER) layers on and off to see the impact of the proposed design. At any point, you can turn off the Proposed Buildings layer to better view the impact.

1. In the Contents pane, turn off the Wind (AFTER) and Proposed Buildings layer and zoom in to the area around the baseball field.

   Notice how the size and shape of the building deflects and channels the wind around the structure. Using 3D symbology, this effect can be observed and understood.

   

2. Turn off the Wind (BEFORE) layer and turn on the Wind (AFTER) layer. Observe the wind direction and speed around the proposed buildings.

   Adding in these new buildings slows air down at the surface level.

   

3. Pan the scene to the west of the baseball field.

   An urban canyon effect can also be observed as the wind is funneled between high-rise buildings and the alleyways between buildings.

   

   Are there any areas where the proposed buildings would result in an urban canyon effect?

4. Turn on the Solar Radiation (AFTER) layer and find areas that have both high solar exposure and slower air flow.

   

   These might be hot spots that need additional trees and vegetation to help mitigate heat.

   How might you modify your wind symbology and your solar radiation symbology to show areas of overlapping slow air and high radiation visually?

In this tutorial, you’ve learned multiple ways of representing thematic data in 3D. You’ve varied data by color according to unique values, by graduated symbols, unclassed colors, and attributes. You’ve varied size by graduated size, proportional symbology, and using extrusion. You’ve represented categories as types of 3D models with varied colors and sizes. You’ve even combined size, color, and orientation to represent complex multiple variable thematic data.

You can find more tutorials in the tutorial gallery.

Acknowledgements

• The data used in this exercise has been contributed by PLW Modelworks, LLC, created using Pictometry images.