KML - Open Source Mapping

A single KML file is a container for multiple geographic objects including points and trails. A KML generated from a GPS can be used with Google Earth or Google Map.

Page Contents

Google Earth Usage

The Google Map must be downloaded and run locally on the users computer, but once installed use with KML files is quite simple. After starting the application, use the File->Open command and select the kml file.

Google Earth File Open

The KML file will appear under the Temporary Places list on the left side.

Google Earth Places

Google Map Usage

Google Map is a network application and runs from web browsers such as Internet Explorer or Fire Fox. This allows maps to be distributed to others without requiring additional software.

Use without a Google Login
First, your KML file must be accessible on a web site. Typically a club would have a web site publicizing their activities, and place the KML file on their site. For this example, use the link http://jtphillips.com/NBATC/NBATC_Composit.kmz

Open your browser to the address http://maps.google.com.

Google Map Image

Enter the web site address for the KML file in the Search Maps field, and then click on the Search Maps button.

Google Map Search Image

This process can be automated. In you clubs web site, include a link that includes the data as well.

<a href="http://maps.google.com/maps?q=http://jtphillips.com/NBATC/NBATC_Composit.kmz">
your lable
</a>

Use with a Google Login
Google requires a free login to store maps within the Google Map site. This is the same login as for a GMail e-mail account. Selecting My Maps and then Create new map will requie this login.

Google My Maps image ==> Google Create new map Button image
Google Account Login image

After logging on to an account, Google will return with left hand menu similar to that in Google Earth. The Import link will pop-up a dialog window to allow you to select the file for up-load.

Google Import Link image

KML Structure

The KML file is a text file that can be edited with a simple text editor, Word Pad in windows for example. This section covers several features of interest. The file NBATC_Composit.kmz will be used as an example.

Header

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.1"
... 		The KML file is written as an extension of the xml structure. The key feature of XML is that all data consists of matching tags like <Folder> ... </Folder> 
<Document>
   <name>NBATC_Composit</name>
This internal document name and the external file name is what appears in the lists on Google Earth or Google Maps. A freshly saved map will likely have to generic name GPS device. Change the document name to something meaningful.

Line Style 

<Style id="lineStyleWhite">
   <LineStyle>
      <color>ffffffff</color>
      <width>3</width>
   </LineStyle>
</Style>
The document can have one or more styles. Keeping with the blaze colors you could have white and blue lines.In addition to white colors are
ffff0000=blue
ff00ff00=green
ff0000ff=red
ff000000=black

Tracks 

<Folder>
   <name>Tracks</name>
   <Folder>
      <name>10-JAN-09AT</name>
	...
The start of the "Folder" containing all of the saved traces, followed by the start of the first trace named "10-Jan-09AT". 
     <Placemark>
        <name>Path</name>
        <styleUrl>#lineStyleWhite</styleUrl>
        <LineString>
            <tessellate>1</tessellate>
            <coordinates>
              -79.391228,37.596837,207.301392
              -79.391020,37.596766,206.820679
The start of the trace information including the line style to be used followed by the trace coordinates (longitude, latitude, elevation).

Editing KML Files


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