Excel tool to calculate Google Earth areas (polygons).
Press the polygon tool in the Google Earth application, and create a polygon.
Organize your polygons in folders and subfolders. You can copy both single polygons and folders of polygons.
In this example the Real Madrid Football arena has been marked:
Right click on the polygon entry and select “copy”.
Open the xls4Oracle Google Earth Area sheet and press the Google Earth Area button in the A1 cell:
A line on the areas sheet is created:
And the details sheet is updated with calculation information:
The Real Madrid Football field size is 68 x 105 meters. You can find 68,33 meters and 105,65 meters in the above sheet.
The area calculation is done by splitting the polygon up into triangles, where all triangles one corner in the 1 point. Each triangle area is calculated using the great circle distance formula. Triangle areas is summarized, where clockwised triangles is added and counterclockwise triangles is subtracted. This can be visualized in this example of a 12 square figure, defined by its 6 corners:
First point is in the lower left corner, second point is the upper left corner and the 3’th corner is in the upper right corner.
Point 1, 2 & 3 defines the 1’th triangle.
Point 1, 3 & 4 defines the 2’th triangle.
Point 1, 4 & 5 defines the 3’th triangle.
Point 1, 5 & 6 defines the 4’th triangle.
Where tringle 1, 2 & 4 are added because they are in clockwise direction of each other, while number 3 is counterclockwise, and is subtracted.
This method can be used on any polygon!