Google Earth Historic Crop Circle Project
The historic crop circle project is your chance to contribute to this unique field of study using the Google Earth historic overlay.


The main aim of the Historic Crop Circle Project is to document and collate historic crop circles using archived aerial photographs. Because the most accessible and easy to use archived aerial photographs are those made available by Google Earth the Project will initially focus on those images however it is hoped that over time other archived aerial photographs will also be studied.

How can you help?

Because Google Earth is free and because it is easy to save images which hold the exact coordinates of a possible historic crop circle each image can be easily checked in context. Also using Google Earth ensures that there are no faked images.

We would like you to start searching the Google Earth historic overlays for crop circles; then, when you find an image you consider to be a crop circle, save the image and email a copy to us. We will then analyse the image, rank it, record its location and give you feedback about the image. We will also publish the image in an on-line archive to be created on this website so that the results of the research will be available, free, to the public.

Register your interest now by emailing me

Where do you search?

At this stage we would like people to start searching anywhere on Earth where there are grain crops. The premise being that if enough people are randomly searching areas all over the Earth, eventually all the Earth will be searched.

When do you search?

Search any of the time periods available on Google Earth, from the earliest to the present. Most areas have a start point in the 1990's with more images available from the 21st century. Each 'time group' is important as we want to establish how many crop circles appear every year around the world and collate any statistically significant geographic or chronological relationships that become evident. We are supposing that not all crop circles that appear each year are noticed or recorded so this system will eventually give a complete record of all available historic crop circles that are available from aerial photographs.

How do you search.

Scanning the Google Earth landscape is relatively easy but it takes a little practice. Usually I set the altitude at around 650 metres above sea level and then use the left < and right > arrows on the computer to move across the screen. Depending on the landscape I either travel along a North South line or an East West line using the longitude or latitude readout provided by Google Earth.

At the beginning and end of each line searched place a numbered marker using the markers provided by Google Earth. Using this method any area can be search systematically.

How do you tell a crop circle from some other circular thing in the landscape?

This is probably the trickiest part of the project and it does require some practice and expertise. There are a number of things to consider which I will now deal with. Through this section, I will include a range of images of circular things I have found during my work that are not crop circles and will discuss each image, for example below is an image of a golf course; because of the poor resolution it would be possible to initially think these were crop circles however there are two ways to check. First, simply move the time bar into the future for a more recent image. Usually a golf course that was there in 1945 will still be there. Second is that other features such as sand bunkers and fairways are usually clearly visible. Practice will make golf courses obvious. Of course there are lots of other circular features in the landscape and we will look at those shortly.

There are two primary challenges in searching Google’s 1945  imagery for crop circles. First is the quality of the original images, which are often, although not always, poor; this means that one has to be extra careful not to assume any circular shape in a field is a crop circle. In fact more than 98% of circular shapes that appear on the 1945 overlay are not crop circles. Most of these can be eliminated easily by using the time slide bar provided by Google. By moving to more modern image overlays of the selected location it is possible to see if the circular shape is repeated. If it is repeated then it is not a crop circle but a permanent landscape feature. Using this method a number of reoccurring circular features, which could be mistaken for crop circles were discovered, these included archaeological remains such as barrows and the foundations of round houses as well as ponds, golfing greens, sports fields, artillery targets, airfield markers etc.

Another source of circular shapes in the 1945 overlay is caused by faults, or flaws, on the film itself, such as in this example below.

Because many of the original negatives used to produce the 1945 overlay were not well preserved there are faults resulting from either mechanical or chemical damage to the negatives. These often show up on the Google overlay as either very bright white circular spots or as lighter shaded rings, both of which might be mistaken for a crop circle.
The example above, which is probably caused by chemical damage to the negative, the bright spot is surrounded by a halo of lighter shading. Whilst this would be a great crop circle it is clear that it is not because the lighter shading includes the hedge and ground beyond the hedge. Also the internal shadow is consistant from all angles whereas the actual Sun's shadow is being cast to the N.N.East. If it was a genuine crop circle there would be a shadow around the bottom rim of the circle and none on the top rim.

This means that to distinguish a film flaw from a genuine crop imprint the presence of a shadow within the circular area, created by the wall of grain at the outer edge of the imprint, is required as a lighter patch caused by damage to the negative will not produce a shadow. Further a direct relationship between the shadow within the crop circle and other shadows present in the image, such as those cast by trees, hedges or buildings, is required before a value is ascribed to the circle.
(see fig. 2)
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Crop circles normally show up in aerial photographs, particularly black and white photos, as a light circular area within the field of a darker grain crop. This effect is caused by the fact that the flattened grain stalks of the circle refract light at a different angle to the vertical grain stalks. This effect is well documented in modern crop circle photography and can also be seen in the difference in shading in partially headed, or  partially mown, fields of grain. There are many examples of half mown fields in the 1945 overlay that clearly demonstrate this contrast (see fig. 1).

The crop circles below are a good example of how Google Earth can be used to locate crop circles that otherwise would have remained undiscovered. The two formations below were found in canola fields in Western Australia by a prospector using Google Earth to search for meteor craters. As you can see the canola has been harvested at the time the satellite image used by Google Earth was taken so the crop circles are not very distinct. The larger  is over 60 meters in diameter