How to Calculate Areas in Google Earthby James Highland
Google Earth is a versatile program that allows anyone to study many aspects of the globe. The application features the ability to spin the earth and zoom in on any area and view satellite imagery, road maps, terrain maps and ground photos of the location. The free version of this software is available for download from the Google Earth site. However, the Pro version offers additional features, including the ability to calculate area between several points on a map. But this version costs $400, as of February 2010. Fortunately, there are free alternatives to calculating area with Google Earth data.
Download the EasyAcreage program that integrates with Google Earth to provide area calculations. This small Windows utility allows anyone to open Google Earth, use its location markers to specify an area, and then output the standard Google KML file used for storing mapping data. This file is then simply dragged with the mouse onto the EasyAcreage window and the area of the marked location is immediately calculated. The units for area as well as distance can be changed among many options, including acres, hectares, square meters, square kilometers, square feet and square miles. EasyAcreage is a particularly simple program to use for getting area calculations out of Google Earth.
Install the GE-Path program, which offers extensive calculations for locations saved by a Google Earth KML file. Like EasyAcreage, GE-Path opens any KML file created in Google Earth and provides further analysis. Area calculations are one of many features provided by this program. It also calculates perimeter length and allows area calculations to be fine-tuned using two different algorithms selected by the user. The ability to add grids and manipulate map colors further enhances the output by the program. GE-Path is a particularly robust choice for users who need many additional features for working with areas specified in the free or Pro versions of Google Earth.
Launch the "Ruler" window from the "Tools" menu in Google Earth Pro if you are using that version. Choose the "Polygon" or "Circle" tabs to outline an area on the map for quick area calculations. The Google Earth Pro version provides this simple interface for getting area measurements, but still does not provide some of the additional features of other free utilities. Users who do not need complex area manipulation tools may find the Pro version acceptable and particularly efficient for their needs. However, Google Earth Pro may still be used with other utilities since it outputs the same KML-formatted files needed for additional processing by other programs.