Exercise 7: ArcGlobe layer classification

Complexity: Beginner Data Requirement: Installed with software Data Path: See Copying the tutorial data Goal: Differentiate the ArcGlobe layer types: Draped, Floating and Elevation, and set properties to improve their display

ArcGlobe classifies layers into three types to help you manage them: elevation, draped, and floating. In this exercise, you'll learn how to use the classifications to help layers provide the right information to your documents. This exercise assumes that you are using default online layers, which require an Internet connection.

If you need to use the system-supplied, coarse layers installed with ArcGlobe, open the default document where you have installed ArcGlobe, for example, C:\Program Files\ArcGIS\Desktop10.0\ArcGlobeData. Set the default layers options, which you learned in exercise 6, to Use my choice of default layers and take a snapshot of the current document.

Adding elevation layers

Elevation layers provide height information to the globe surface. You'll use rasters with height source information to provide topography to the surface of the globe and make it look more realistic.

Steps:

1. Start ArcGlobe by clicking Start > All Programs > ArcGIS > ArcGlobe 10.
If you have ArcGlobe already open from a previous exercise, simply click the New Globe File button to create a new globe surface.

2. In the ArcGlobe-Getting Started dialog box, click Browse and set the default geodatabase path to D:\3DAnalyst\3D_Default.gdb, if it is not already.
3. If prompted, click No to close the Save changes to Untitled ArcGlobe document warning. If you are continuing from exercise 6, you do not need to save the previous exercise's results.

ArcGlobe starts, and its default layers are loaded.
4. Click the List By Type button in the table of contents to show the default layer classifications.
5. Right-click Globe layers, point to Add Data, then click Add elevation data.

This indicates that you want to add a specific type of data to that layer category.
6. Navigate to the location of the Exercise7 folder.
7. Select sw_usa_grid.
8. Click Add.

The raster is added to the elevation category and will be used as a source of elevation for the globe surface.

Adding draped layers

Draped layers are placed on the globe surface and use any elevation data present to show base heights. Next, you'll add images that will be draped on the globe surface in the area you added elevation data.

Steps:

1. Right-click Globe layers, point to Add Data, then click Add draped data.

Layers you now add will follow the globe surface.
2. Click angelus oaks.tif, press CTRL, then click socal_mmosaic.sid.

Both layers are selected.
3. Click Add.
If prompted with Create pyramids for angelus oak.tif message box, click Yes to create pyramids for rapid display at varying resolutions.

Close the Geographic Coordinate Systems Warning message box. The data will be projected to ArcGlobe's currently set Geographic Coordinate System.

4. Right-click angelus oaks.tif and click Zoom To Layer.

The display zooms to the extent of the layer. A few moments will pass before the layer is shown at full resolution as the on-demand cache is built. Once the cache is built, you'll be able to revisit the area and display the layer quickly.
5. Click and hold the socal_mmosaic.sid layer and drag it so it is just above the Imagery layer in the table of contents.
A black line indicates where the layer will be placed.
6. Release the mouse pointer to drop the layer in its new position.

The socal_mmosaic imagery is being displayed on top of the Imagery layer due to its higher drawing priority

Setting a target to initiate Surface mode

Steps:

1. Press CTRL and click the middle of the display.

You've initiated Surface mode and set a target at the location on the globe surface where you clicked.
2. Click the bottom of the display and slowly drag up.

The globe surface you created becomes discernible as you investigate the imagery you added.
3. Click the Full Extent button to return the display to the original view.

Adding floating layers

Floating layers are layers that float independently of the globe surface. Next, you'll add a raster as a floating layer and set it to elevations not connected with the globe surface.

Steps:

1. Right-click Globe layers, point to Add Data, then click Add Floating Data.

2. Click o3_99x10k.
o3_99x10k is a raster showing average annual ozone concentration for 1999 in California.
3. Click Add.

The layer is added to the floating category.
Close the Geographic Coordinate Systems Warning dialog box. The data will be projected to ArcGlobe's currently set Geographic Coordinate System.

Setting elevation properties of floating layers

Steps:

1. Right-click o3_99x10k and click Properties.

2. Click the Elevation tab.
3. Click Floating on a custom surface.
4. Click the drop-down arrow and click sw_usa_grid.
5. Type 5000 in the Add a constant elevation offset in meters text box.

6. Click the Symbology tab.
7. Select the red to blue color ramp from the Color Ramp drop-down arrow.
8. Check Invert.
This inverts the color ramp so that high values will be displayed as red, low values as blue.

9. Click OK.
You've set the raster to use its own values as a source of base heights, offset those heights 5,000 meters from the globe surface, and symbolized the concentration values with color. Next, you'll take a look at how this appears in the display and set a vertical exaggeration to accentuate the elevation.

Setting a vertical exaggeration factor for floating layers

Steps:

1. Right-click o3_99x10k and click Zoom To Layer.

The layer is displayed in the view.

2. Click the Navigation Mode button to change the mode to Surface navigation.
3. Click the bottom of the display and slowly drag the mouse pointer up.

This allows you to see the effect of changing the vertical exaggeration.
4. Double-click Globe layers.

5. Click the General tab.
6. Select or type a value of 10 for vertical exaggeration Of floating layers.

The floating layer will be exaggerated by a factor of 10.
7. Click OK.
Examine the floating layer you created. You'll see a 3D raster showing average ozone concentrations in California in 1999. The layer floats above the state of California and is a surface that is different from the terrain below. Applying 3D raster layer transparency is useful for overlapping data such as terrain or aerial photography, and a pollution raster as shown here.

In this exercise, you learned how to differentiate layer types in ArcGlobe, saw the effect they have on the globe, and set properties to improve their display. Explore the Exercise7.3dd globe document in the Exercise7 folder to discover additional ways to enhance your globe documents. The document contains layers saved with custom settings, bookmarks, globe lighting, and animation tracks.