UFO Hot Spots?
If you haven't already, read the page on the quality and limitations of UFO data in order to understand the background for these maps.
Let's consider the case of North America, excepting Mexico. The overall rate of reports for the United States and Canada indicate the rate of reports received form 1947 to 2007 is comparable. Can we identify the famous UFO hot spots?
Data from the entire database for the period 1947 to 2007 was taken (114,233 UFO sighting incidents). The number of sightings within each square longitude and latitude was determined (where precise geographic location information was available, in 90,777 cases). For each latitude and longitude, this data was plotted using a 'black body radiation' intensity scale, with the least sightings being black, going through red to orange to yellow and finally white. In these maps, light gray are uninhabited areas; dark gray are inhabited latitude/longitudes with no UFO reports; and latitude/longitude areas with UFO reports are in the black to white intensity scale. First consider the raw number of reports on a worldwide basis:
What can be seen here is only the 'data hole' for developing countries. The map looks pretty much like just a map of population density of developed countries. Not too useful. It's interesting to note the sightings along the oceanic air routes of the 1950's (an artifact of USAF Project Blue Book reports). These routes had to be used due to range limitations of early airliners and transports. So we see a string of black dots indicating sightings over uninhabited ocean between Midway and Alaska, Newfoundland and the Azores, California and Hawaii, and so on. Otherwise not too informative. So let's consider just the raw data for North America:
This again looks pretty much like a map of population distribution. In particular the hot spots are the major cities - San Francisco, Los Angeles, Chicago, New York, etc. These aren't really sighting hot spots, just areas where more people live.
So let's plot the sighting rate instead - the number of sightings per population in each longitude/latitude grid square. We use the UNEP database of this data for 1990:
Now this is more interesting. Areas of average sighting rate are red. Those below average dim down to black; those above average run from yellow to white-hot. But there are only two locations that really stand out, in British Columbia. The rest seem to be either red or black. Recall the discussion of sighting rate versus local population density in the data discussion. What we have here is just a map that shows the lower population areas of America. We need one final refinement. Consider if we chart the ratio between the observed rate of reports and what we would expect if the average relationship between local population density and sighting rate occurred:
Now the real hot spots emerge. There is a sea of red - these are the average values, where the expected number of UFO sightings has occurred - whether in high or low population density areas. But there are certain orange-to-white locations, and these are where sightings are greater than average. And where are they? Near major US nuclear and defense installations…