Google Earth Resources for Educators

Google Earth Vocabulary:

Placemark – A location in Google Earth

Tour – a collection of placemarks in a specific order.

Layer – A set of data that is displayed on a map.  In Google Earth, these consist of placemarks, overlays, shapes, or paths.

Static layer – A set of placemarks or overlays that do not change.

Dynamic layer – A set of placemarks overlays that is pulled from an online source.  The information in the layer can vary according to context or as the information is updated on the remote server.  This is also known as a “Network Link” in Google Earth.

Overlay – An image placed on top of a Google Earth map, outside of a placemark.

KML (Keyhole Markup Language) – This is the basic file type for Google Earth.  KML is a type of XML file formatted specifically for Google Earth.

KMZ (Keyhole Markup Zip file) – A KMZ file is a KML file in zipped, or compressed format.  Images in placemarks and overlays can be included in a KMZ file, but cannot be included in a KML file.

Keyhole – The program now known as Google Earth was first produced by a company called Keyhole, Inc.  Keyhole also refers the original KH spy satellites; a reference that compares spy satellite technology to peeping through a key hole.

Tag – Tags are similar in function to keywords.  The difference is that a keyword is added by the owners of the data before the data is posted, and a tag is added by users as they see the relevance of the data through a process called “tagging.”

Geotag – A specific type of tag that indicates that the item has spatial coordinates associated with it.  These tags are meant to be read by other programs.  Usually these come as a set of three tags, as indicated below:

geotagged (indicates that the item has geo data)
geo:lat=xx.xxxxxxx (the latitude of the item in decimal degrees)
geo:long=yy.yyyyyyy (the longitude of the item in decimal degrees)

HTML (Hypertext Markup Language) -   This is the basic language of the World Wide Web.  HTML codes tell how text, images, and other items should be formatted for web pages.

XML (Extensible Markup Language) - This is a method of transferring data from one information source to another.  It uses strict rules of formatting, and is often used to produce data seen in web pages.

GIS (Geographic Information System) – A program that can display import data and display on a map.

Geocoding – The process of matching data with locations on a map.  Data items can be geocoded against street addresses or latitude and longitude coordinates.