Range Rings for Google Earth (RINGS)
This page describes a free application that runs in
Google Earth. Please install
Google Earth,
download
RINGS,
and return to this page to learn more.
RINGS is an online tool that draws concentric circles, an annulus, or a sector of an annulus
in Google Earth. Ring radii may be specified from 10 to 1,000,000 US survey feet or meters,
and from 0.25 to 10,000 miles (1 mi = 5280 US survey ft), nautical miles (1 nmi =
1852 m), or kilometers. Line and area colors are selected from a 24-color palette,
line width may be specified from 0.1 to 10, and area opacity may be specified from
0 to 100%.
-
Position the point of interest (POI) in the center of the view. One way to
do this is to double-click an unmarked location. To precisely position the
POI in the center of the view, add a placemark at the desired location;
then edit the properties of that placemark and reset the view
(explain).
-
Check the box beside the Setup network link.
A form will be presented with read-only coordinates corresponding to
the view center and input fields for ring parameters. Range rings are
drawn when the Draw button is pressed.
-
On subsequent uses, reposition the POI and ensure that the network link
is checked and selected. Then choose Refresh from the Edit menu,
or right-click and select Refresh in the context menu
(explain).
© 2013 Google - Image USGS
Ring radii are integral multiples of the user-specified Normal
Radius Interval. The minimum radius interval is 10 for feet or meters
and 0.25 for miles or kilometers. A maximum of 200 rings may be drawn per query.
To suppress index rings, set the Index Radius Interval
to any value greater than the Ending Radius, or set the normal
and index line colors and widths to the same respective values.
An annulus or sector of an annulus with arbitrary radii may be drawn instead of
rings by selecting Annulus or Sector on the input form. To draw a
disk or sector of a disk, enter 0 for the Starting Radius. Enter 0 for
Opacity to draw only the boundary of sectors. Sectors that cross the
antimeridian should be drawn with zero opacity to avoid a known Google Earth issue.
Annuli and disks that cross the antimeridian should instead be drawn as rings.
Range rings are rendered as regular polygons with 72 vertices on the WGS84
ellipsoid using Vincenty's
nested
equations. The computed vertices typically exhibit submillimeter agreement
with the NGS online
Inverse/Forward computation utilities.
Note: To save range rings from one Google Earth session to another, right-click
on Saved Regions and select Save to My Places.
RINGS is a component of
Earth Survey
© 2007-2013
Metzger + Willard, Inc.
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