My Google Map Blog

With the recent update to the Google Earth ocean floor data it is worth having a look at some of the patterns we can see and what causes them. In the past, some of the patterns have been mistaken for an alien base or Atlantis. However, most of the stranger patterns are merely an artifact of how the data is collected, processed and combined with other data-sets.

In the area around Hawaii, we can see a lot of streaks and swirls. This is a result of an algorithm used to interpolate the sea floor depth between data points and does not reflect the actual appearance of the sea floor. In the above screen shot there is no depth data for most of the central region of the image where the streaks can be seen.

When zoomed out we can often see tracks (1) of higher resolution data, which are the tracks of ships equipped with sonar that mapped the ocean floor along their route. In many cases they have concentrated on mapping the joints between tectonic plates (2) that are of particular interest to oceanographers and geologists.

The tracks also show us the routes the ships took. In the above image we can see the routes fan out from the southern tip of Tasmania as that is the route that would be taken by any ships coming from the east of Australia. Similar patterns can be seen elsewhere, with a fan shapes around Hawaii, the west coast of the US, Cape Town, South Africa, and a number of other locations. There seems to be a popular destination in southern Chile, but the tracks fade away as they approach the coast, so we weren’t able to identify the exact destination. A lot of the ships also went through the Panama Canal. The tracks are highlighted in a graphic in this article that we looked at on Monday. The ships’ tracks are much less visible near the coasts, most likely because higher resolution data is available for shallower coastal waters.

The global low resolution dataset used for the ocean floor is the Scripps map, which is based on satellite measurements of gravity. Although the map gives us a good idea of the large scale structure of the ocean floor it does not show the details and any given measurement may be quite different from the Scripps map. A single measurement will often stand out as a hill or dimple in the overall map, when in reality it may be an unremarkable point on the ocean floor.

In the above image from a location near Guam, we see an area where there has been a survey done with depth measurements taken at very regular intervals. The pattern is caused by combining those measurements with another lower resolution dataset that has a different average depth, so each measurement appears as a dip or bump.

The same effect as mentioned in the previous image can be seen here, but with fewer data points.

As we have mentioned before Google Earth often shows different ocean floor data depending on how zoomed in you are. This is very noticeable around Hawaii and Guam.

The post Understanding Google Earth Ocean Floor Data appeared first on Google Earth Blog.

Last week we talked about a recent update to the Google Earth ocean floor data. As we mentioned in that post, the ocean floor data is a combination of data obtained from satellites and published by the Scripps Institution of Oceanography, University of California, San Diego and higher resolution data gathered by ships. We came across this article that gives more detail on the data gathered by ships. The article says that Lamont-Doherty Earth Observatory has been gathering the ship data and their data has been incorporated into the Google Earth map. From the article:

The Google ocean map, covering the entire ocean floor, relies mostly on data collected by satellite that is curated by the Scripps Institution of Oceanography, in partnership with NOAA, the U.S. Navy and the National Geospatial Intelligence Agency, with contributions from the Japan Agency for Marine-Earth Science and Technology and Australia Geosciences-AGSO. It also incorporates the more precise data from Lamont.”

There is also this YouTube video that highlights some of the areas in Google Earth that have received high resolution data.

Also mentioned in the article is this map called Marine Geoscience Data System (MGDS) and we found that in many places it matches what can now be seen in Google Earth. However, we found some locations, such as the one below, for example, where the MGDS maps is noticeably higher resolution than the Google Earth ocean floor data but the parts we can see clearly come from the DGDS data set.

Just off the coast of Portugal.

One of the locations mentioned in the article, Scott Reef, clearly shows the data has been imported into Google Earth but has lost some resolution.

Some of the ocean floor data is obscured by satellite imagery.

The post Another look at the new Google Earth Ocean data appeared first on Google Earth Blog.

In late 2014 we had a look at a map of the ocean floor published by the Scripps Institution of Oceanography, University of California, San Diego. . Apparently that map was incorporated into the Google Earth ocean floor data just before the New Year. Read more about it here.

Note that what appears in Google Earth is a combination of the Scripps map and a variety of other sources, including sonar data gathered by ships. Google Earth does not have historical imagery for ocean data. We have noted before that the ‘historical imagery’ mode does show a different ocean floor map, but there is no easy way to find out what Google Earth showed a few months ago other than keeping screen shots. We don’t have many screen shots of the ocean floor, but [this post]((http://www.gearthblog.com/blog/archives/2015/04/historical-imagery-ocean-floor.html) does have a screen shot taken in April 2015, so we can compare that with the current location in Google Earth today.

As far as we can tell, a number of undersea mountains have disappeared in the new data. We believe this represents errors in the older data that have been corrected.

We can also compare the current Google Earth data with the Scripps map as published here in KML format.

The Google Earth data (right) is clearly higher resolution than that version of the Scripps map (left).

The Scripps sea floor map has also been used to discover a new microplate in the Indian Ocean.

The post New Sea Floor Map for Google Earth appeared first on Google Earth Blog.

Google Earth’s 3D view of the Ocean floor was first introduced in version 5. It has been improved a number of times since then. Panaromio photos in the oceans were added in 2010 and underwater Street View in 2012.

Google’s current ocean floor data comes from a number of sources, including:

• Ship bathymetry data. Learn more about it in this post.
• An extrapolation of water surface heights to estimate undersea mountains and canyons, based on radar data collected by satellite.
• Satellite data on slight variations of the pull of gravity over the oceans.

One of the organizations that has provided this data in the past is the Scripps Institution Of Oceanography, University of California, San Diego. Yesterday, they released some new data from the satellites CryoSat-2 and Jason-1, including global maps of the sea floor that they have released in KML format so they can be viewed in Google Earth. Read more about it and download the KMLs here. Be sure to watch the video featured on that page, which explains more about it.

The post Exploring Ocean Tectonics from Space appeared first on Google Earth Blog.