Creating an Immersive User Experience
Google Earth allows you to put your content into a geospatial context. Moreimportantly, it allows you to tell stories. In this tutorial, you'll learn some ways to make your content accessible, easier to navigate, and more compelling.
The Google Earth Interface
There are three main ways people will interact with your KML through the Google Earth interface:
- Places panel
- 3D map
- Your description balloons
To design an immersive experience for people viewing your content, consider the most common path that visitors take. Start by scanning the map in the 3D view, explore a few placemark balloons, and discover the full range of options in the Places panel. Make sure your design starts with a solid foundation on the map itself.
Here are examples of KMLs that provide an immersive, high-quality visitor experience :
Make a Good First Impression
The first thing most people see when they open a KML or KMZ file are the icons, models, image overlays, and polygons in the 3D view of Google Earth. It's your job to engage them and get them interested in exploring your content. Below are some tips for making a good first impression.
Setting a good default view for your placemarks and folders is one of the most important things you can do to ensure a good user experience.
- Double-clicking a placemarks flies you to its current default view. If you haven't explicitly set one, this view could be too close to the placemark.
- Pick a perspective for each placemark. Don't get too close if the surrounding satellite imagery is low-resolution; if there is high-resolution imagery, make the best of it!
- Don't always look straight down! Tilt the camera
to capture the local terrain, or match the perspective from real photos in the placemark's
- To set a placemark's default view right-click on a placemark, either on the map or in the Places panel, and choose Snapshot view.
Too many placemarks can be overwhelming, even for the most experienced Google Earth visitor. Here are some ideas for keeping the number of placemarks manageable:
- Use regions to control when placemarks become visible. For help getting started with regions, check out the Regions section of the KML 2.1 Tutorial and the Avoiding Overload with Regions tutorial on this site.
- Combining network links and regions provides a powerful method of dynamically delivering content to visitors based on their location. Learn more in the Smart Loading of Region-Based Network Links section of the KML 2.1 Tutorial.
- You don't have to put everything in one KML or KMZ file. Include links to other KML or KMZ files in your placemark balloon descriptions for the visitors to download on-demand.
You can communicate plenty of information before a visitor even clicks on a placemark. Here are a few helpful hints for using icons effectively:
- Use custom icons. Google Earth makes it easy to use your own images
as icons. Here are some custom icons from the Featured Content layer:
- Select different icons for different types of locations. You might use one icon for
major hospitals and another for smaller field clinics.
- Don't use an icon if a text label would be better. If a placemark has no description
for visitors to read, click No Icon on the Icon properties window. (To
display the Icon properties window, right-click the placemark, select
Properties, and then click the icon to the right of the Name field.)
- If you don't want your icon to have a square shape, use transparency when you save
the images, as shown in the following examples from the Global Awareness
GIF and 8-bit PNG images support areas of basic, on/off transparency, and 256 colors. 24-bit PNG images support alpha-transparency (partial transparency; translucent appearance), 16 million colors, and are the best choice for Google Earth icons.
- Icons on the 3D map are ideally 64 x 64 pixels. For larger or smaller icons
use 32 x 32, 128 x 128, and other dimensions that are factors of two
(2^x), because they scale better in Google Earth.
- Keep it simple. Avoid using text in the icon, as it will be illegible at small
- Select a clean design that will inform without being distracting.
- Use different colors for lines, polygons, and icons to visualize data or represent
classes of locations.
See this example from the Crisis in Darfur layer which uses different colored polygons to represent displaced people and refugee camps, as well as different colored icons to represent partially damaged and completely destroyed villages:
- Choose colors for icons and line/polygon features that contrast against the satellite
imagery in the background.
The use of yellow lines in the Global Heritage Fund layer stands out against the green forest in the background.
Create Balloons That Shine
Once you've gotten a visitor to open one of your placemark balloons, make the best of their attention. Placemark description balloons are a great way to communicate extra information about a particular location, but they're also a powerful tool for guiding viewers to other placemarks and your web site.
You know your content much better than anyone else, so it's easy to forget that others need guidance to explore all of your content. Consider including an introductary placemark to guide the use of your KML file. Highlight the most different components of your content. Some suggestions for what to include:
- An overview of your organization and work.
- Screenshots of the Places panel or time slider to guide visitors to the best way to navigate your content.
- Explain the use of icons or colors used in your KML.
Here are examples of a user's guide and an introductory placemark from the Global Awareness
layer (Global Heritage Fund and Crisis in Darfur).
The best balloons engage the user, offering a brief description with links to additional information. You can always direct the user to your site for the full story or invite them to download additional KML files with more detailed information.
Continuing this philosophy, keep your balloons to a reasonable size. Put all of your
content into an HTML table no wider than 400-500 pixels. This helps ensure that the
balloons aren't too big on small monitors and that there is a little space left for the
user to see and click back to the map.
A consistent look and feel in your balloons orients your visitors. Get started with some templates you can create with the Building Better Balloons tutorial. As you develop your own designs, keep some of these tips in mind:
- Use slightly different balloon design to indicate different types of placemarks. Consider using distinct border colors to denote environmental threat levels or programs on different continents. You could also use more ornate layouts for different levels of hierarchy within your content, such as international, national, regional and local offices, research locations, or humanitarian aid projects.
- Use a header. Create a banner with your organization's logo and either a consistent color or an eye-catching photo for the top of each balloon.
- Include a footer. Always put your organization's name, a link to your website and a copyright notice at the bottom of all your balloons. Use a gray or light color font, so that the footer text is accessible but not distracting.
- Use color schemes from your organization's web site to help create a cohesive experience.
- Take advantage of text color. Use color to add or diminish emphasis to titles and captions.
- Use standard icons, such as the KML icon, if your balloon includes links to such additional content.
For an easy way to add consistent headers and footers to each of your balloons, check out
tags. These tags allow you to create an HTML template that is applied to all of your
placemarks. You can insert the descriptions unique to each placemark into the template.
This keeps the universal elements of your balloon design separate from the content specific
to each placemark.
The Santa Cruz, Bolivia example KML shows you how placemarks can use <BalloonStyle> for the header and the footer. (This example was modified from UNEP's Atlas of Our Changing Environment layer.)
By using the <bgcolor> and <textColor> tags with <BalloonStyle>, you can specify a background color for the entire balloon. You enter 8-digit hex codes for colors, such as AABBGGRR (R - red, G - green, B - blue, A - alpha transparency). This is different than the traditional 6-digit hex codes used in HTML (RRGGBB). Here are two ways to choose a background color in Google Earth:
- Try the KML Color Picker.
- If you know the HTML color code you want to use, swap the last two characters with the
first two characters, and add "FF" to the beginning to make this a fully opaque color. For
example: for HTML color: #0066CC, use FFCC6600 (FF + CC6600).
Gombe Chimp Blog and Background Color Examples (modified from the Jane Goodall'sGombe Chimpanzee Blog)
Don't Forget the Places Panel!
Although many visitors are drawn in by the 3D view in Google Earth, it's also important to keep the view of your KML file in the Places panel organized and useful.
- By default, Google Earth shows the first two lines of a placemark's description below its name. This is called a Snippet. Reclaim this often wasted space by specifying an empty snippet in your KML as follows:
<Snippet></Snippet> <description>Lots of interesting information!</description> ... </Placemark>
- Often, when you save your KML project, Google Earth saves your features into a
<Document> container. You'll recognize a document by its icon:
By default, a document's name is the same as the name of the KML file itself. This name is often uninformative, if not confusing. Avoid using characters that are illegal for file names ( / ? < > \ : * | ). If you try to save a folder named "Offices: 2007" or "Local/Regional", Google Earth won't let you save the feature. You can fix this problem by re-opening the KML file, renaming the top-level document, and saving it, overwriting the original file.
- Below is an example of a good and bad name for a document - "bgColor Examples" versus
- By using <ListStyle> and <ItemIcon>, you can change the default icons for folders, documents, placemarks, and other features.
- Brand your layers by using your organization's logo for the top level documents and folders. This technique is especially useful if you want to hide the content of a folder but want that folder to visually represent the placemarks it contains. (See "Avoiding clutter" below for more information about hiding the contents of a folder.)
- List icons are scaled down to 16 x 16 pixels, so, for the best results, use images with those exact dimensions.
- See the official KML 2.1 Reference
and the examples below
- Keep the list view of your KML file short and organized.
- Include no more than 2-3 levels of hierarchy within your documents.
- Where exposure of certain placemarks is important, save the KML with the folders open; otherwise, leave them closed.
- Control the contents of a folder from the list view using the <ListStyle>
- Radio folders allow visitors to turn on only one item in a folder at a time.
- Check Hide Children for folders to conceal their contents – a great idea if you have hundreds or thousands of placemarks inside!
- Check Off Only so folders can be turned off, but not turned on – great for folders that have lots of models or intense polygons and paths. Visitors can't turn on everything at the same time and overwhelm Google Earth.
Discussion / Feedback
Have questions about this tutorial? Want to give us some feedback? Visit the Google Earth Outreach Discussion Group to discuss it with others.