Google Earth User Guide - Manual (Page 73)

Remove selected point If you want to remove a point from either a
path or an area shape, select a point and
press the Backspace key.
Remove all shapes You can clear all measuring shapes from
the viewer by clicking on the Clear All
button in the Ruler dialog box regardless of
which tab is active.
Reposition the viewer By default, navigation with the mouse is
disabled when you use measuring mode,
but you can enable it by checking Mouse
Navigation. When enabled, mouse
navigation works in conjunction with
measuring: click and hold to add a new
point; click and drag to move the earth.
Line All Google Earth versions support
measuring with a line. A line consists of
two points connected by a straight line,
and measurement is done along its length.
Path All Google Earth versions support
measuring with a path. A path in the
measuring mode consists of two or more
points connected with a straight line.
Measurement is done along the entire
length of the path. To follow a natural
boundary or road more closely, try
zooming in closely to the feature and
adding more points.
Polygon Google Earth PRO version supports
measuring with the polygon tool. A polygon
consists of three or more points.
Measurement for a polygon tool is done for
both perimeter and area.
Circle Google Earth PRO version supports
measuring with the circle tool.
Measurement for a circle is done for its
radius, area, and circumference (in the
appropriate measurement unit).
Available Units of Measure
The following table describes the units of measure available for length, perimeter,
area, and radius.
Feature or Function Description