Historical Imagery and the Ocean Floor

An interesting aspect of the ‘historical imagery’ feature in Google Earth is that when you turn it on Google Earth displays a different dataset for the ocean floor. Based on the copyright information, it appears the ‘historical imagery’ ocean floor is based on data from NASA, whereas the ocean floor seen in the default view is a combination of data from Data SIO, NOAA, U.S. Navy, NGA and GEBCO.

Historical Imagery view
The NASA supplied data as seen in ‘historical imagery’

Default view
The default view with data from a variety of sources

It is interesting how whole underwater mountains are completely missing in the NASA data and some locations look quite different in the two data sets. The NASA data is of lower resolution and presumably obtained by a different method.

Another interesting effect is how satellite imagery that extends into the oceans is mapped onto the sea floor topography. If necessary you can correct this in Google Earth Pro by turning off ‘Terrain’ in the layers.

As we have noted in the past the tracks across the ocean floor are not signs of alien activity, but tracks of higher resolution data obtained from ships.

We have looked at the GEBCO data before and you can view their map in Google Earth using this KML file.

We have also looked at a map from the Scripps Institution of Oceanography, University of California, San Diego, which is based on gravity measurements from satellites. You can view it in Google Earth with this KML file.

For best results when viewing the ocean floor, turn off the ‘Water Surface’ option in the ‘View’ menu.

About Timothy Whitehead

Timothy has been using Google Earth since 2004 when it was still called Keyhole before it was renamed Google Earth in 2005 and has been a huge fan ever since. He is a programmer working for Red Wing Aerobatx and lives in Cape Town, South Africa.






PLEASE NOTE: Google Earth Blog is no longer writing regular posts. As a result, we are not accepting new comments or questions about Google Earth. If you have a question, use the official Google Earth and Maps Forums or the Google Earth Community Forums.

Comments

  1. Puzzling are the LINEARS seen in Shallow depths of Puget Sound! These mostly Orient East to West in Holmes Harbor- a Dead End Lobe terminating at Freeland, WA. Angles are small, departing from 90-270, and they are Similar to Planets’ Inclination angles from the Ecliptic Plane. Interesting for the slightly Murky Waters is the YELLOWISH COLOR! Thinking that there was a Sulfur connection, I talked to Crabbers who probe the Waters: “No way, you can see the Bottom on Google Earth!”
    Nevertheless, I found that they appear whenever there are Juts (pointing to Bays on the Opposite side-such as Honeymoon Bay), making it Appear that the Holmes Harbor had EXPANDED E-West, Shearing along these Lines! Solve the MYSTERY, of the YELLOWISH LINES?
    Porogle.blogspot.com

    • http://Timothy%20Whitehead says

      That is aerial imagery captured in strips and then stitched together.



PLEASE NOTE: Google Earth Blog is no longer writing regular posts. As a result, we are not accepting new comments or questions about Google Earth. If you have a question, use the official Google Earth and Maps Forums or the Google Earth Community Forums.