My Google Map Blog

Tag: Google Earth Engine

More about the new Landsat / Sentinel 2 data in Google Earth

by Timothy Whitehead on Nov.30, 2016, under 3D Models, Argentina, Australia, Brazil, California, Denmark, England, Germany, Google Earth News, Google Earth Tips, Google Sky, Google maps, Hawaii, Indonesia, Ireland, Italy, Japan, Kenya, Mexico, Natural Landmarks, Netherlands, Sightseeing, Street Views, USA

Yesterday Google surprised us by adding global mosaics created from Landsat and Sentinel 2 data to the Google Earth’s ‘historical imagery’. The data comes to Google Earth via Google Earth Engine, which has long had this time-lapse feature that has just been updated to include imagery up to 2016. The timelapse page also tells us more about the imagery:

Using Earth Engine, we combined over 5 million satellite images acquired over the past three decades by 5 different satellites. The majority of the images come from Landsat, a joint USGS/NASA Earth observation program that has observed the Earth since the 1970s. For 2015 and 2016, we combined Landsat 8 imagery with imagery from Sentinel-2A, part of the European Commission and European Space Agency’s Copernicus Earth observation program.”

Google Earth Engine has also published this post about the update.

On Friday we will release a KML file that will allow you to view similar time-lapses from directly within Google Earth.

Today we are making a few observations about the imagery.

The first observation comes from GEB reader ‘haflaa’ who points out that although the mosaics are global for every year between 1985 and 2016, there are some locations, such as the Maldives, where the imagery is identical for a number of years. In the case of the Maldives, the imagery is identical from 1985 to 1999.

We also note that the Google Earth Engine animation starts in 1984, whereas the Google Earth data starts with December 1985 (which we presume represents the data for the whole of 1985).

The path of the satellite is often noticeable in the imagery. For more on the orbit of the Landsat satellites see this post and this post.

In many locations you will notice narrow stripes in the imagery. This is because of a faulty part on the Landsat 7 satellite. Learn more about it in this post.

The mosaics are created by trying to select imagery from throughout a given year then selecting cloud and snow free pixels where possible. However, there are a few locations on earth that are almost always cloudy, a problem we discussed in this post.


This location in Cameroon features both Landsat 7 stripes and clouds that just could not be eliminated.

The post More about the new Landsat / Sentinel 2 data in Google Earth appeared first on Google Earth Blog.

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Global Fishing Watch

by Timothy Whitehead on Sep.19, 2016, under 3D Models, Argentina, Australia, Brazil, California, Denmark, England, Germany, Google Earth News, Google Earth Tips, Google Sky, Google maps, Hawaii, Indonesia, Ireland, Italy, Japan, Kenya, Mexico, Natural Landmarks, Netherlands, Sightseeing, Street Views, USA

Although it is not directly related to Google Earth, Global Fishing Watch does use geographic ‘big data’, so we thought it would be worth covering. Global Fishing Watch is a partnership between Google, Oceana and SkyTruth, which aims to track the world’s fishing fleets and monitor where they fish. This will help to identify illegal fishing as well as assist in the management of fisheries. Read more about it on Google’s Lat Long blog.

To use it, start here. It requires you to sign up to use it, but the signup process is fast and free. We believe the signup is required because of the sensitivity of the data and they require you to acknowledge that you realise the data may be inaccurate, among other things. Learn what you can do and how to use it from the tutorial here.

They do not provide an API nor any way to export data to Google Earth. The data can be accessed by their research partners via Google Earth Engine. They state, however, that the underlying ship tracking data is a commercial data-set, so they cannot distribute it freely. We really wish that shipping data and aircraft data could be made available freely, but Global Fishing Watch states that it downloads 20 million data points per day, so whoever is managing the data collection must have significant costs. There are sites such as MarineTraffic for ships and FlightRadar24 for aircraft that let you see real-time data for a significant proportion of the world’s shipping and aircraft, but if you want any historical data it has to be paid for. We have long wanted to get hold of some historical tracks so we can write algorithms to find ships and aircraft in historical imagery, but we have not managed to find any source that provides such tracks free of charge.

We came across this interesting track that follows lines of longitude (every four degrees). And then another ship takes over and continues the pattern further west. Was it doing some research as well as fishing?

The post Global Fishing Watch appeared first on Google Earth Blog.

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Land lost vs. land gained

by Timothy Whitehead on Sep.13, 2016, under 3D Models, Argentina, Australia, Brazil, California, Denmark, England, Germany, Google Earth News, Google Earth Tips, Google Sky, Google maps, Hawaii, Indonesia, Ireland, Italy, Japan, Kenya, Mexico, Natural Landmarks, Netherlands, Sightseeing, Street Views, USA

We recently came across this interesting article by National Geographic about a recent study of land/water changes over the last 30 years. The study is by researchers at the Deltares Research Institute, who used Google Earth Engine to gather and process the data. The data itself comes from Landsat imagery.

Sadly, we were not able to figure out a way to view the data in Google Earth. Google Maps Engine (not to be confused with Google Earth Engine), which was shut down earlier this year, was notable for being able to easily display maps in Google Earth. However, it appears Google Earth Engine does not have any such features and is mostly focused on displaying data in Google Maps style 2D tiles. This is a pity, because we find Google Earth a much better platform for exploring this kind of data.

The researchers published the full description and analysis of the project in the journal Nature Climate Change, which is subscription based. However, the data itself is published as a publicly available 2D map.

What we were not able to determine were the details of how the water bodies were measured. Most inland water bodies are quite seasonal, so we wonder how the researchers corrected for that. The Landsat imagery typically covers each spot on earth once every 16 days, but a fairly high percentage of the images are obscured by cloud. This often means only a few good images per year. For the global mosaic used in Google Earth, many different images over multiple years are combined together to get the cloud-free image. However, this can result in some weird effects where water is concerned, because water is not just seasonable, but can vary considerably from year to year (more on this in a future post). Droughts or floods can, for example, be one-in-a-hundred-years events. This doesn’t apply to coastal land reclamation, which tends to be permanent.


Land reclamation near Seoul, South Korea, as seen in Aqua Monitor.

We have previously created animations of land reclamation and artificial islands being built, but we restricted ourselves to the time-frame visible in Google Earth historical imagery, rather than the 30 years used in the above study.

The post Land lost vs. land gained appeared first on Google Earth Blog.

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Google My Maps vs Google Maps

by Timothy Whitehead on Oct.01, 2014, under 3D Models, Argentina, Australia, Brazil, California, Denmark, England, Germany, Google Earth News, Google Earth Tips, Google Sky, Google maps, Hawaii, Indonesia, Ireland, Italy, Japan, Kenya, Mexico, Natural Landmarks, Netherlands, Sightseeing, Street Views, USA

As mentioned in this recent post, users that have custom maps are being migrated from the Classic My Maps to Google’s new version of My Maps which was formerly Google Maps Engine Lite. This information pertains to the desktop web versions, not the mobile apps.

So let us have a look at the observable differences between the new Google My Maps and Google Maps, and how it effects Google Earth users. The following post is based entirely on observations made while trying the products and it is important to remember that we have no direct knowledge of the actual technology used behind the scenes.

Both Google Maps and Google My Maps appear to share the same basic mapping data, such as the street map, public transit maps, and points of interest, but beyond that, there are very significant differences between the two.

Google Maps

  • This is again the new Google Maps (also known as the “preview” option).
  • It is dynamic. Click on any place on the map, and the map changes, highlighting subtly important features relevant to the location you clicked and hiding features that are less relevant.
  • It is personal. If you have signed in, then your saved places places will be shown, and possibly your home and work locations if Google knows them. Your current location may also be shown if you wish.
  • It has Street View, including Historical Street View, which cannot be accessed in Google Earths Street View, nor in the older version of Street View.
  • It has Earth view, including 3D imagery and the ability to tilt and pan the view in a way that is similar to Google Earth, but in a number of ways significantly different. Most notably, the 3D view can only be viewed from the four cardinal directions and two specific angles.
  • It has web versions of Google Moon and Google Mars similar to those in Google Earth. There are currently no ‘My Moon’ or ‘My Mars’ products. In Google Moon and Google Mars in the new Google Maps Earth View, there is no search functionality, whereas in the desktop application Google Earth, there is both search functionality and many selectable layers. Plus you can create KML content on the Google Earth versions of Moon and Mars for your own use, or to be shared with others via KML.
  • It has only two base maps – the background image that the map data is overlayed onto. There is the default street map view, which shows significant variation over the different zoom levels, and there is the satellite imagery in Earth View.
  • It has a new rendering engine with a smoother feel when zooming in and out. Also screen updates tend to be done for the whole screen at once rather than in a tiled fashion.
  • It includes the ability to give directions.
  • It has traffic information for some locations.

Google My Maps

  • This is the new Google My Maps, not the classic version. It was formerly Google Maps Engine Lite, and still has references to the old name of “My Places” which was the tie to Google Earth.
  • The new My Maps lacks many of the features of Google Maps, including dynamic changes, personal features, Street View, 3D imagery, tilt, Google Moon, Google Mars, and traffic information.
  • They have just recently added a limited ability to import KML – but, KML import has limitations (see this help page at bottom). You can still import KML with the older My Maps/Places and then import the map into the new My Maps. You can also export the map in KML so you can view it in Google Earth. If you choose the network link version you won’t be able to view off line. (See help page).
  • It has 9 basic base maps available, with each one having optional settings, such as turning off the streets or other features.
  • Although you can add directions as part of your map, a user viewing your shared map cannot get directions.
  • It provides the ability to create your own map, including points, lines, polygons, and directions – this is, after all, its primary purpose. But, the user interface is different from the classic version.
  • It allows you to share the map in either editable form with collaborators, or in read only form. You can share with individuals or with the public.
  • It includes tools to measure distances and areas. Note that measuring areas in Google Earth is only possible in the paid version Google Earth Pro.

Google Maps
Above: Google Maps
1. More information about a place.
2. Directions and Traffic data
3. Save as favorite in your personal map.
4. Street View, photos and reviews.
5. Related places have been shown. We clicked a stadium, so other stadiums and football clubs were highlighted.
6. Limited 3D viewing similar to Google Earth including 3D Cities, Moon/Mars.

Google My Maps
Above: Google My Maps
1. Fewer options on a selected place.
2. Topology base map, not available in Google Maps.
3. Limited ability to import/export KML for use with Google Earth.
4. Alternative view is ‘Satellite’ view and not ‘Earth’ view.
5. Fewer controls.

It is actually possible to preview a My Maps map in Google Maps, but I could not find a way to share one in that way.

The takeaway from all this? Do not expect the users of your My Maps creations to have the same experience they would in Google Maps on the desktop. It is a different product with a different engine under the hood. If you use Google Earth to create your mapping content, you may find limitations in importing the KML to the new My Maps verses the classic version. Similarly, the export of KML is different from the classic version.

[Update: Thanks to GEB reader Marko Zlatic for pointing out that Google Maps' Earth view can be rotated and tilted freely by holding down the Ctrl key (in Windows, I assume the Command key works on Mac) contrary to the statement in the post above that it is restricted.]

The post Google My Maps vs Google Maps appeared first on Google Earth Blog.

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