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Needs Analysis > Pierce County Trails: Google Earth™ and KML File Tutorial

Pierce County Trails: Google Earth™ and KML File Tutorial

Pierce County Trails: Google Earth™ Tutorial

Pierce County is in the process of planning for its regional trails network. The first phase allowed us to collect data from a number of sources, including individuals contributing trails information using Google Maps™, to develop an inventory of existing and planned trails in Pierce County. At this phase of the process we have inventoried the existing and planned regional trail alignments. The inventory is presented in several formats.

You can find the PDF trails inventory on the Needs Analysis page of the Pierce County Regional Trails Plan TownSquare website. Additionally, PDF Maps and a folder of KML files are located in the Documents Library. All are available for you to download. The use of Google Earth™ is intended to supplement your review of the Draft Needs Assessment Summary Report available for download here: http://www.piercetrailsplan.org/docs.php?oid=1000000119.

This guide is intended to specifically introduce you to using the KML files in Google Earth™. This guide will not teach how to use everything in Google Earth™, but will let you interact with the trails information developed to date. If you would like a tutorial on how to use Google Earth™, please visit the Google Earth™ User Guide at http://earth.google.com/userguide/v4/ug_toc.html.

What is Google Earth™?

Google Earth™ is a desktop virtual globe, map, and geographic information database program available for download from Google. We recommend you play around and get use to the many features it has.

What is a KML file?

KML is a file format used to display geographic data in an earth browser, such as Google Earth™, Google Maps™, and Google Maps™ for mobile. A KML file is processed in much the same way that HTML (and XML) files are processed by web browsers. Like HTML, KML has a tag-based structure with names and attributes used for specific display purposes. Thus, Google Earth™ and Maps act as browsers for KML files.

You can use KML to:

  • Specify icons and labels to identify locations on the planet surface;
  • Use image overlays attached to the ground or screen;
  • Define styles to specify feature appearance;
  • Write HTML descriptions of features, including hyperlinks and embedded images; and
  • Use folders for hierarchical grouping of features.

System Requirements

To use Google Earth™ on a Windows PC, you must have at least the following:

  • Operating System: Windows 2000, Windows XP, Windows Vista;
  • CPU: 500Mhz, Pentium 3;
  • System Memory (RAM): 256MB minimum, 512MB recommended;
  • Hard Disk: 400MB free space;
  • Network Speed: 128 Kbits/sec (DSL or Cable will work fine);
  • Graphics Card: 3D-capable with 16MB of VRAM;
  • Screen: 1024x768, "16-bit High Color" screen; and
  • DirectX 9 (to run in Direct X mode).

To use Google Earth™ on a Mac, you must have at least the following:

  • Operating System: Mac OS X 10.4.11 or later;
  • CPU: G4 CPU, 1GHz or faster;
  • System Memory (RAM): 256MB minimum, 512MB recommended;
  • Hard Disk: 400MB free space;
  • Network Speed: 128 Kbits/sec;
  • Graphics Card: 3D-capable with 32MB of VRAM; and
  • Screen: 1024x768, "Thousands of Colors".

Regarding Linux, Google Earth™ has been tested on Ubuntu version 6.06, but certainly works on others. Hardware requirements include:

  • CPU: 500Mhz, Pentium 3;
  • System Memory (RAM): 256MB RAM;
  • Hard Disk: 500MB free space;
  • Network Speed: 128 Kbits/sec;
  • Graphics Card: 3D-capable with 16MB of VRAM; and
  • Screen: 1024x768, "16-bit High Color" screen".

If Google Earth™ appears to be slow and unresponsive, it is likely that your system needs different video drivers.

Using Google Earth™ and KML Files

Figure 1. Download Page for Google Earth 4.3

1. Download and install Google Earth™ from http://earth.google.com/download-earth.html. We recommend downloading Google Earth™ 4.3 rather than the latest 5.0 Beta. This will allow you to easily use the features discussed in Step 8. Based on this, please use the link we provided. When you click the link, you should be a page that looks like Figure 1. The download link for 4.3 is under the heading “Download the previous version”.

2. Download the full zip KML files from the Pierce County website: http://www.piercetrailsplan.org/docs.php?ogid=1000000068. Unzip these files into one folder.

3. Let’s open the KML files in Google Earth™.

  • File > Open > Find the folder where the KML files are located and select all the KML files, then click Open.
  • Or drag the KML files directly in the Google Earth™ window and they will be added automatically.

4. Google Earth™ will now zoom to Pierce County where you can view all visible KML attributes. In the left column in the Places Menu, you will see the layers located under Temporary Places.

  • Note: When you close Google Earth™ the next time, you will be asked to save any files in Temporary Places to My Places. Save them to My Places so you that the next time you open Google Earth™, you will easily access them without importing them again.

5. All of the files will be selected and viewable. We recommend that you deselect all of the boxes so that you can begin to view each layer separately. Some of these layers are on top of each other and may not be viewable with multiple layers selected.

Figure 2. Layer Organization Screenshot

6. Let’s look at what each layer is and determine what is useful attribute information. See Figure 2 for a screenshot of how the layer layout is shown in Google Earth™. Those layers marked with an ** in the list below are considered more useful attribute information. The others layers are less useful because they contain only default ID information. The order of these layers is recommended for best viewing.

  • **Regional Trails (off-street): This layer depicts existing and proposed regional trails. The features in this file are organized by trail name listed in the inventory and throughout the Needs Assessment Report.
  • **Regional and County Parks: This is a point layer of Pierce County’s regional and county parks as defined in the adopted PROS Plan 2008.
  • Existing Trailheads: This is a point layer of existing trailheads. There is no attribute information associated with this layer. These are depicted on all maps within the Needs Assessment Report.
  • Proposed Trailheads: This is a point layer of proposed trailheads. There is no attribute information associated with this layer.
  • Regional Trail Concept: This is the regional trails concept described in the Needs Assessment Summary Report and represents the proposed spine of the regional trail system. The regional trail concept is discussed on pg. 25 of the Needs Assessment Summary Report.
  • **Trails by Trail Class: This file depicts the classification of the existing and proposed off-street paved trails described in the Needs Assessment Summary Report. Each trail segment is classified into on of the three trail classifications: regional, sub-regional, connector. The trails are defined on pg. 25 and 26 of the Needs Assessment Summary Report.
  • **Bikeways by Trail Class: This layer depicts the on-street bikeway linkage opportunities described in the Needs Assessment Summary Report. Each bikeway segment is classified into one of the three trail classifications: regional, sub-regional, connector. Bikeways are discussed in the trail linkage opportunities on pg. 17 of the Needs Assessment Summary Report.
  • **Roadways by Trail Class: This layer depicts the on-street linkage opportunities described in the Needs Assessment Summary Report. Each road segment is classified into on of the three trail classifications: regional, sub-regional, connector. These are discussed on pg. 21 of the Needs Assessment Summary Report.
  • **Water Trailheads: This is a point file of the Washington Water Trails Association identified water access points for Washington’s water trails.
  • Water Trails: This file depicts Washington’s water trails in the Sound. There is no attribute information associated with this layer.
  • County Boundary: This layer represents Pierce County’s jurisdiction.

Figure 3. KML Features Screenshot

7. Each KML file has a number of features for you to access. Expand any layer by clicking the + button. This will reveal the attribute folders in each layer. Click on them to see what is available. See Figure 3 for what it looks like in Google Earth™.

  • You can click the box with the green check mark to turn a layer off or on.
  • If you want to know where a layer is located on the map, double click the name of the layer and the map will zoom to that location.

Figure 4. Viewing Information Screenshot

8. To interact with the map, you can click on any point or line.

  • You can view the information on a point layer by moving your cursor to the point (colored circle) and clicking on it. Figure 4 shows what you should see if you click on a point.
  • You can view the information on a line layer by moving your cursor to any location on a line and clicking on it.

Remember to have fun and experiment with Google Earth™. Thanks again for your assistance. For questions or comments, please feel free to contact Heather Kaplinger at info@piercetrailsplan.org or 1-877-297-1003.

If you'd like to have a PDF of this page, you can find it here.

Source: Google Earth™ http://earth.google.com