Loading a local .kml file using google maps?

Question

I created a hello world program to load a local kml file (borrowed from google's docs):

var ctaLayer = new google.maps.KmlLayer("http://localhost:8080/kml/cta.kml");

This does not work (nothing gets loaded).

However, when I change that line to:

  var ctaLayer = new google.maps.KmlLayer("http://gmaps-samples.googlecode.com/svn/trunk/ggeoxml/cta.kml");

it loads properly. Both kml files are identical. What do I need to do to get it to load when serving it myself? (I tried both absolute and relative paths, and I know the paths I am using are correct...)

Also I added the correct mime type to my appserver's config file:

<mime-mapping>
    <extension>kml</extension>
<mime-type>application/vnd.google-earth.kml+xml</mime-type>
</mime-mapping>
<mime-mapping>
    <extension>kmz</extension>
    <mime-type>application/vnd.google-earth.kmz</mime-type>
</mime-mapping>

But it still doesn't load.

I found this in google's docs:

The Google Maps API supports the KML and GeoRSS data formats for displaying geographic information. These data formats are displayed on a map using a KmlLayer object, whose constructor takes the URL of a publicly accessible KML or GeoRSS file.

So I guess what I am trying to do is not possible without serving the kml from a publicly accessible url...unless someone can prove otherwise

Answer 1

Your localhost:8080 web server is likely not providing the proper Content Type header for KML files, while googlecode.com does. I had this issue when I worked with KML.

The proper header is:

Content-Type: application/vnd.google-earth.kml+xml

Answer 2

The KML can't be accessed since it's on your local machine and google can't access that since it doesn't know where localhost:8080 .

Answer 3

It took me a while to find this answer. Can Google please put this information in their API reference?

Answer 4

Unfortunately you cannot use "localhost". You have two choices:

1. place the kml on a publically available domain. (if google cannot access it, it won't work)
2. Use geoxml3 which basically does what google does but allows you to downlaod and host the parser JS file youself. It will allow you to load a LOCALHOST KML and parse it out for you (objects accessible via JSON) (http://code.google.com/p/geoxml3/).

Choice #1 might not be an option for those working on defense contracts and deal with sensitive information as the kml is sent to google in the background and rendered on the map.