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Google Earth Blog
In June last year the Google Chrome team announced that they would be ending support for NPAPI based plugins by September 2014. NPAPI is an ageing technology used by, most notably, Java, Silverlight and the Google Earth plugin. It is being dropped largely because it is considered a potential security risk.
In September Google released a 64-bit version of Google Chrome that did not include support for the Google Earth plugin or other NPAPI based plugins. However, the 32-bit version still supported it and has continued to support it. Over time, however, Chrome has been making it increasingly difficult to run NPAPI plugins, requiring the user to explicitly allow a plugin to run before displaying it.
Now, Google has just released Chrome version 42 that drops support for NPAPI plugins by default. It is still possible to get them back is via a Chrome flag, but presumably that option will soon be disabled too.
For now, if you really need the Google Earth plugin in Chrome 32-bit, you can reenable NPAPI by entering the url: chrome://flags/#enable-npapi in the address bar then selecting ‘Enable’ below the ‘Enable NPAPI’ section then relaunch the browser.
The Google Earth plugin itself was deprecated in December and is set to stop working on 12th December 2015.
Firefox is also slowly phasing out NPAPI plugins and as far as we know the latest Internet Explorer only allows them in the 32 bit version in compatibility mode and not at all in the 64-bit version.
The post Chrome now making it harder to use the Google Earth plugin appeared first on Google Earth Blog.
When looking around Google Earth in historical imagery, we have noticed an interesting trend with regards to the frequency of satellite imagery updates. It seems that Europe and the USA get significantly less satellite imagery than much of the rest of the world.
Although much of the less populated world has rather poor and infrequent coverage, some population centres seem to get very frequent updates. Here in Cape Town we have recently been getting several updates per month. We were recently looking at an area near Santos Dumont Airport, Rio de Janeiro, Brazil, and it has no less than 12 images so far in 2015. Even the relatively small town of Livingstone, Zambia has had two updates this year. Many large cities in the US and Europe, such as New York, San Francisco, Paris, Berlin and London still have 2014 imagery.
We have been wondering why this is. We will make a few guesses, but would welcome input from our readers too.
The USA and Europe are covered with high quality aerial imagery and thus new satellite imagery, which is of lower resolution, is usually relegated to ‘historical imagery’. Possibly Google, or the satellite imagery providers they source the imagery from, do not see the need for satellite imagery in those regions. Aerial imagery is typically more expensive to gather on a regular basis although we expect this to change in the future with as the cost of drones and high resolution cameras continues to fall.
Google tends to avoid satellite imagery with excessive cloud cover, and most notably, snow cover. So does this essentially mean that much of the Northern hemisphere will never get good coverage over the winter months?
Some of the recent Cape Town images can be explained as a ‘special event’ where imagery has been captured and put in Google Earth because it contains something interesting:
To see general trends up to October last year, this map is interesting. We hope Google updates it at some point to show more recent months.
The post Frequency of new satellite imagery in Google Earth appeared first on Google Earth Blog.
As part of an advertising campaign for the Hyundai Genesis, Hyundai have used the cars to write a message from a girl called Stephanie to her father who works on the International Space Station.
The message was created on January 18th, 2015 and holds the Guinness World Record for the largest tire track image. The image is not yet in Google Earth, so we have created an image overlay based on a screen shot from the YouTube video.
We had a look at the location in the Landsat imagery, but the sand is so bright it is not possible to see whether the writing is still there. Let’s hope DigitalGlobe or another satellite imagery provider got a good image and we see it in Google Earth eventually.
It is not the largest artwork ever made with tracks in sand. That title, we believe, is held by Jim Denevan, whose Black Rock Desert piece we have looked at before. He apparently used a roll of chain fencing pulled around by a truck. Also featured in that post is the Mundi Man or Eldee Man by Ando, drawn in Australia using a tractor, but it is quite a bit smaller than the Hundai message. The Nazca Lines of Peru are much older and were created by removing reddish pebbles from the surface exposing the lighter ground underneath.
If you are as interested in maps as we are, then you probably already know and follow Google Maps Mania.
Yesterday, April 13th, they turned 10! Happy Birthday!
They were initially focused on Google Maps, but back then there weren’t that many other on-line maps available. Now, however, there is an extraordinary variety of maps out there. To give you a taste, just in the last few weeks they have covered:
And much more. So head on over and have a look!
We recently came across this post on Reddit. It references a YouTube video claiming to have discovered the longest straight line that can be sailed without going over land. The video creator calls it the Cooke Passage. However, we have attempted to recreate it in Google Earth, and it appears that it is not actually a straight line.
We have in the past discussed what constitutes a straight line in Google Earth. In this instance, we are interested in great circles, which is what Google Earth uses by default when drawing a path. However, Google Earth always draws the shorter arc of a great circle, so to draw the longer section of a great circle it is necessary to include at least one more point and then adjust it with care. You know you have got it right if you can draw another shorter path on any section of it and it still follows the same path.
Using the above techniques, and locations shown in the video, we have investigated the Cooke Passage and decided that it does not follow a great circle.
It seems the record for the longest straight line that you can sail is a route from Pakistan to Siberia, which you can read more about here or see it featured in the following YouTube video:
We also came across another interesting, though shorter route that goes from Norway to Antarctica by way of the Bering Strait.
To see the various routes discussed in this post in Google Earth, download this KML file
Thank you to GEB reader Chris for pointing out in the comments that Google’s new 3D imagery adds some further complications to the story.
Google’s 3D imagery is created from aerial imagery captured from different directions then combined to create 3D models. In some cases, Google has included a set of aerial imagery captured at the same time in the ‘historical imagery’ layer. The easiest way to identify such imagery is to look for a construction site in the 3D imagery and then try to find a matching image in ‘historical imagery’.
Left: 3D imagery of a construction site in Berlin, Germany. Right: The same location as seen in the aerial imagery dated May 20, 2013 seen in ‘historical imagery’.
When Google adds 3D imagery, the additions are not outlined on the Imagery Updates map, but instead, Google publishes a map specifically for 3D imagery. They update the map rather infrequently and it shows locations but not exact outlines. So, we at GEB maintain a KML file showing the outlines of all areas discovered so far that have the new 3D imagery. It is maintained with the help of GEB readers who let us know about new additions in the comments of this post and the assistance of GEB reader Anton Rudolfsson who marks out the outlines of the newly discovered imagery. A big thank you to all contributors.
The new Google Maps and the latest Android version of Google Earth display the 3D imagery by default and do not have a means of turning it off. As a result, locations with 3D imagery will look different in Google Maps and Google Maps Classic. In Google Earth, to hide the 3D mesh, you can either switch to ‘historical imagery’ (which turns off the new 3D imagery and shows any legacy 3D buildings) or turn off the 3D buildings layer.
Left: Google Maps Classic. Right: New Google Maps.
Above we can see a construction site in Pardubice, Czech Republic. In Google Maps Classic we can see aerial imagery including 45° imagery captured in December 2008. In the new Google Maps we see 3D imagery captured circa September 2013. In Google Earth we can see the same 3D imagery, or switch to ‘historical imagery’ and see a whole range of dates up to June 2014.
To find the locations mentioned in this post download this KML file
The post Understanding Google’s Imagery Updates map part 3: 3D imagery appeared first on Google Earth Blog.
Yesterday we looked at Google’s Imagery Updates map and what it tells us. We mentioned that the imagery being added is not always current imagery. So you may be asking why Google would add old imagery and why imagery is not always added to the default layer.
Google gets its imagery from a variety of sources. Google captures quite a lot of aerial imagery itself, especially in the US and Europe, including, we believe, the imagery used to create the new 3D imagery. However, a large amount of the aerial imagery that can be found in Google Earth was obtained from other sources. For example, the US has a complete set of black and white imagery mostly captured in the 1990s, provided by the U.S. Geological Survey (USGS) and more recent imagery from the United States Department of Agriculture (USDA) Farm Service Agency.
Google gets its satellite imagery from providers such as Digital Globe and Airbus Defence and Space and for the low resolution image used when you zoom out, Landsat imagery is used. If you look at the copyright notices in Google Earth you can tell where the imagery comes from. Note that many of the copyright notices refer to the sources of other map data, such as the street maps or ocean floor data.
We don’t know the exact details of any agreements Google has with the imagery providers, but presumably many of the providers wish to sell imagery to their customers first, before making it essentially freely available in Google Earth. So if you want up-to-date imagery of a specific location, you will need to purchase it directly from an imagery provider. Only a small fraction of the imagery they capture ever makes its way into Google Earth.
When Google receives imagery, it assess both the age and quality of the imagery and decides whether it is better than the imagery currently at that location in Google Earth. If Google Earth already has aerial imagery that is of higher quality, newer satellite imagery will often be put straight into ‘historical imagery’ leaving the aerial imagery as the default. So if you notice an area has fairly old imagery and you want something newer, be sure to check ‘historical imagery’ to see if there is anything more recent available.
Another common reason for adding imagery only to the ‘historical imagery’ layer is when it is of poor quality, but something of interest. In some cases such images really stand out due to the large amount of cloud cover.
An unusual patch of cloudy imagery.
If you see something like the image above in ‘historical imagery’ then it is likely there was something of particular interest at that location. In this case, is was damage caused by a tornado that hit the town of Pilger, Nebraska.
The post Further comments on understanding Google imagery updates appeared first on Google Earth Blog.
Last week Google published a map titled ‘Monthly Google Earth Imagery Updates’, which contains a layer called ‘Satellite and Aerial Imagery Updates March – 2015′. So what does this map tell us?
The map displays red outlines of areas where Google has obtained satellite or aerial imagery and added that imagery to their various databases during the month of March. The first thing to note is that the imagery itself was not necessarily captured during the month of March. Some of the imagery was captured in March, such as the image of Wadi Sayyidna, Sudan, captured on March 4th, 2015. However, imagery is typically a month or two old, and sometimes much older, such as an image of Taipei, Taiwan, captured on January 25th, 2014.
Google has several different imagery databases and it is usually the case that the imagery is added to these databases at different times. These databases are:
- The default view in Google Earth.
- The ‘historical imagery’ in Google Earth.
- The Google Maps imagery as viewed in ‘Earth’ view.
- Classic Google Maps in ‘Satellite’ view.
A popular method for finding or confirming new imagery is to compare the above sources and look for differences. Typically, the Google Maps imagery is eventually synchronised to be identical to Google Earth’s default imagery. However, imagery that goes straight into Google Earth’s ‘historical imagery’ and not the default layer may never be visible in Google Maps.
Left: Google Earth default view. Right: Google Earth ‘historical imagery’.
Left: Google Maps Classic. Right:Google Maps ‘Earth’ view.
As can be seen above, the latest image of Livingstone, Zambia, captured by Digital Globe on January 27th, 2015, as of this writing, has been added to Google Earth, but not yet to its ‘historical imagery’. It has also been added to Google Maps Classic, but not yet to the new Google Maps.
It is often the case that when Google releases an imagery update map, that some of the imagery is destined for the ‘historical imagery’ database only and has not actually been added to it yet. Thus we can see outlines on the map, but cannot view the actual imagery it is referring to, and must wait a week or so for it to get put into ‘historical imagery’.
Two red outlines over the northern half of Taiwan.
As can be seen in the above screen shot, Google has outlined two areas over the northern half of Taiwan. As of this writing, the left hand outline does not match any image found in ‘historical imagery’ nor does it obviously match any imagery found in the default layer. It is most likely an image that will in the near future be visible only in ‘historical imagery’. The outline on the right, matches an image from January 25th, 2014 which can be seen in ‘historical imagery’ but not in the default layer.
Note: To see imagery dates in Google Earth, first deselect the ‘Monthly Google Earth Imagery Updates’ map layer if you have it open.
Last Friday, Google made an announcement that they plan to “retire” the Google Earth Community (GEC) forums starting May 1st. Google wants to continue managing the Google Earth product help forums, but let the community migrate to something new. So, at the same time, Google is supporting the announcement of a new Google Earth Community run by the same group of volunteer Google Earth enthusiasts who have been instrumental in its creation and popularity during the past 10+ years (see below for more explanation). The new forum software is much more like the original GEC community (when the GEC was most popular) and will have some key technical advantages which were limiting the community’s effectiveness in the past. I especially like the part in the Google announcement where they say: “…we look forward to sharing new and exciting updates to Google Earth with you in the future.”
Google’s announcement really isn’t about closing down the Google Earth Community. Google intends to keep the existing posts (and KML content) available in read-only format so people can see the content, and the GEC layer will still be viewed in GE. This also means that hopefully the countless links to interesting stories on the GEC will stay preserved. This change in the community is really a decision that should have happened sooner.
Years ago, the GEC had become a source of data for Google Earth. Early in Google Earth’s history database connections between the forum and Google Earth were created. One was a decision to allow anyone to make a post in GEC from within Google Earth. Another, is a layer that allows notable placemarks by the community to be shown in a GEC layer in Google Earth (see layer in GE called: “Gallery->Google Earth Community”). When the GEC reached its max in popularity, it outgrew previous forum software, Google engineers thought they could do better. They took product support forum software and attempted to “enhance” it to make it into a community support forum with features of the previous GEC. But, it didn’t work as they hoped. The same feeling of a community just wasn’t there. It wasn’t long after the transition that many enthusiasts of the forum started leaving – or at least they didn’t stay and linger on a regular basis like before. And the GEC has continued to dwindle in activity ever since.
Moving back to a community forum platform, with many of the original enthusiasts, may actualy reinvigorate the GEC. I spent time this weekend with the new GEC and it feels much more like the older better platform, and the older better community. Many of the people who were part of the older community are already enthusiastically posting some of their favorite old stories, and significant new content is being added as well. I think it is off to a great start, and I hope the new forum will for a while avoid the influx of random people who have no conception of a community forum, or real enthusiasm for the information for which the GEC was created. And, now the lack of ties to the database between the GEC and Google Earth will take the pressure off in ways that, in my opinion, will actually improve the quality of the community.
For those of you who really like Google Earth, and perhaps were fans of the older GEC, I suggest you give the new Google Earth Community a try. I think it will be better. Google Earth has exponentially more data than ever before, and the opportunity to discover and share things is far greater today than ever in the past. Even though the product hasn’t seen new features, it is still getting better because of the data. This new forum will show people things they never dreamed could be found, and learn things about people and places they never knew.
And, maybe the new GEC can put their heads together and help convince Google to breathe new life into Google Earth. There’s a lot that can be done to make the product better. Sometimes the users of a product have to force a company realize the true value of what they have and do something about it. I, for one, am not giving up on Google to keep Google Earth going. It’s a product that is far better than Google Maps in many ways, and its technology could be evolved into new and exciting directions that could become even more useful to the world at large.
Meanwhile, the Google Earth Blog will continue to share some of the better stories from the new GEC whenever possible and encourage enthusiasts to join the new Google Earth Community.
I’ve written some more background information about the Google Earth Community for those who want to know more. See below:
When Google Earth was first released (2005), it already had a strong core of people who were enthusiasts. This is because Google Earth was an application that came from a product called Keyhole that Google bought in the previous year (2004). These Keyhole enthusiasts had already formed an online forum where they shared things they discovered in the imagery of the Earth. It wasn’t just about finding your house to these people, they would find significant historical sites and tell the story about the history. Or point out how the imagery captured an airplane in flight and identify what type of planes, and then categorize all the planes found. There’s a whole world of information out there and these people enjoyed knowing and sharing more about the places they found. One of the best things about Google buying Keyhole and making Google Earth was Google also greatly increased the amount of data. Now these enthusiasts had far more places to discover and write about.
One of the smartest things Google did when they first released Google Earth was to also welcome this community of enthusiasts and supported them while Google offered the forum to the much wider community of users who downloaded Google Earth. In the matter of just a couple of years, the number of registered forum members went from a few thousand, to over a million! And, the amount of in-depth and interesting content about our planet revealed through all this new data similarly grew exponentially. Some of the core enthusiasts became “moderators” of the forums with administrator priveledges allowing them to curate the stories that people shared in the forums to make sure they were properly categorized, appropriate material, and to enhance the quality of the data whenever possible. The job was enormous, and few people have a real appreciation of just how hard the job was to moderate content from so many people. Many people would share data that was simply wrong, non-sensical, or worse, malicious. The moderators have done an amazing job of reducing the influx of poor information while highlighting the useful and interesting contributions, and often enhancing it.
When Google Earth Blog started shortly after the release of Google Earth in 2005, many of our stories were based on content first posted in the GEC. And that has continued ever since. The moderators have not only provided pointers to useful stories, but they also often create very interesting Google Earth-based content themselves and many have been featured in the blog as well.
The Google Earth Community moderators worked tirelessly for years (and many still do) on a volunteer basis with a very noble goal of not only providing quality information, but trying to maintain a quality community of people who enjoyed sharing knowledge, about the data found in Google Earth, and enthusiasm. Google again did a smart thing and recognized the value of these people and supported annual face to face meetings for the moderators, who worked from many parts of the world, so they could recognize their efforts, and provide a means for them to work better together to keep the forum and Google Earth running effectively.
The bond between some of the moderators and other enthusiasts has been strong. Many have developed lifelong friendships because of the community. And, as usually happens in a community, there have been friendships broken, and friends lost. And, I imagine the deterioration of the community has not been a pleasant experience. I sure hope that the new GEC will generate some new excitement and I’m sure there will be new and interesting content and community members. Here’s hoping the new GEC will last a long time – along with Google Earth.
It is the same map that was used for the February updates so the February map is no longer available. Due to the way Maps Engine uses a proprietary network link, it is not possible to save the data shown on the maps as a KML. The only way we know of to keep a record is via a screen shot. We hope Google will update its Historical Imagery Updates map, which as of this writing still only shows up to October 2014.
Monthly Google Earth Imagery Updates – March 2015
Note that some of the imagery has not yet been put into ‘historical imagery’ and if it isn’t being added to the default layer, it may not be visible at all.
So, have a look around the new imagery and let us know if you find anything interesting. We notice there is new imagery in Nicaragua around the site where construction of the Nicaragua Canal will begin. If any of our readers can spot early signs of construction please let us know. It is in the very early stages of construction so we would expect to see access roads being built, not the actual canal.
Our favourite find so far is Concordia Research Station in Antarctica:
Concordia Research Station, Antarctica.
We recently came across an excellent map of the theatres of Great Britain posted on Google Groups. The creator Sue Bunch has put a lot of work into it, with most Placemarks including a photo of the theatre, a short description and links to the theatre’s website and Wikipedia page. To view it in Google Earth grab the KML file here
Theatre map of Great Britain, by Sue Bunch.
We are highlighting this map because it is becoming less common to find good quality maps created and shared in formats suitable for Google Earth. Maps Mania features many interesting maps, but the vast majority of them are displayed in a 2D web-based format with no option to export to KML and view them in Google Earth.
Even maps presented on Google’s own Google Maps are not always readily viewable in Google Earth. To illustrate this problem the map featured in this post is also available in a Google Maps version. Although there is an option to download the map as a KML file, the map is in five layers, and there is no option to download and view all the layers at once. So although one could download each layer separately, it is a bit cumbersome to get all the layers into Google Earth. In addition, the KML export does not handle the images correctly, so the resulting map in Google Earth does not show the images.
We were asked by a GEB reader whether the satellite imaging companies would be collecting and publishing satellite imagery of Vanuatu. DigitalGlobe has a subscription service called ‘First Look’ that provides access to timely satellite imagery for disaster zones. It is targeted at crisis response organizations. It does not provide the imagery directly to the public. DigitalGlobe does, however, have a publicly available map showing what imagery is made available via the First Look service and it appears that satellites World View 1 and World View 2 have captured a number of images over the last few days of the island of Efate where the capital of Vanuatu lies.
In addition, the New Zealand Herald has published sections of a few of the images showing comparisons of before and after imagery.
DigitalGlobe’s First Look coverage map.
Also on DigitalGlobe’s map you can see the locations of other recent events that you may not have heard of, such as the eruption Costa Rica’s Turrialba Volcano, the eruption of Chile’s Villarica volcano or flooding in Lobito, Angola.
We hope that DigitalGlobe makes the imagery of these locations available to the public at some point in the future, or even better, that they get into Google Earth.
Last year we had a look at Satellogic, a satellite imaging company that is planning to launch hundreds of imaging satellites. However, they are still in the very early stages of development and have only launched a few experimental satellites.
Today we are looking at Planet Labs a satellite imaging company that has already launched 71 imaging satellites and claim to have the largest such fleet in space. They are focusing on gathering global imagery on a regular basis at a relatively low cost. Their imagery is relatively low resolution, at around 3m, but is improving with each generation. For this reason we are unlikely to be seeing their imagery in Google Earth any time soon, as Google prefers high resolution imagery, preferably aerial imagery, and if that is not available then high resolution satellite imagery, such as Digital Globe’s recent 30cm offering.
In comparison, Google’s SkyBox Imaging has launched only 2 satellites of a planned constellation of 24, but they are capable of sub metre resolution and HD video.
For more see the following TED talk by Will Marshall, the CEO of Planet Labs.
This is the twelfth in our series showcasing the Google Earth plugin. This Friday, March 20th, 2015 there will be a total solar eclipse. We have looked at number of eclipses in the past and one of our favourite tools is the HeyWhatsThat website’s eclipse page that makes excellent use of the Google Earth plugin. It features two panes, one showing the expected path of the eclipse on the earth and the other, using Google Sky, shows the current position and path of the Moon across the sky. Remember that most browsers will require you to give the plugin permission to run.
The total eclipse will only be visible along a narrow band north of Scotland, but a partial eclipse should be visible from much of Europe, weather permitting.
Another useful site created by Xavier Jubier has a list of eclipses and corresponding KML files that you can download to view the path of the eclipse in Google Earth. The relevant KML for Friday’s eclipse can be found here
The post Google Earth plugin showcase: HeyWhatsThat eclipse appeared first on Google Earth Blog.
Google added a number of new 3D areas over the weekend, amongst which was Niagara Falls, which lies on the border of Ontario, Canada and New York State, USA. For a list of other newly discovered 3D areas, check the comments at the end of this post or download our KML file, keeping in mind that it takes us a day or two to get new locations into the KML. Also of note in the new finds are Zagreb, Croatia (a new country, and capital city) and Prague, Czech Republic (a capital city).
Although Niagara Falls does have the old type of 3D model which includes an impressive spray effect and a rainbow, we feel the new imagery gives a much better overall effect as the whole region is modelled and the colours match well. You can still view the old model if you wish by switching to ‘historical imagery’.
Google’s automatically generated 3D imagery usually does very poorly with moving objects such as aircraft, cars, and water. Google has clearly had to manually touch up the model as it usually does for bridges and some buildings. If you get too close the edge of the Horseshoe Falls looks a bit too angular and the trees on the islands are not in 3D. The rapids above the American Falls have some major flaws in the 3D if you look up close. However, if you don’t get too close, the overall quality of the imagery is impressive and worth having a look at.
We believe the 3D imagery was captured prior to May 2013.
We have in the past looked at the some of the California fault lines where earth quakes are likely to occur.
A recent story in the news is that a recent report by the Working Group on California Earthquake Probabilities (WGCEP) shows that the probability of an 8.0 magnitude earthquake happening in the next 30 years in the California region is higher than previously thought.
The interesting part from a Google Earth perspective is that WGCEP has provided a KML file showing the fault lines in the California region and the associated probability of a large earthquake happening in the next 30 years. You can download the KML here.
Google Earth has an Earthquakes layer in the Gallery, provided by the US Geological Society (USGS) which shows historical large earthquakes globally. In addition, the USGS provides various KMLs that show all the recent earthquakes over a magnitude of 1.0. You can find them here.
If you want a global view of the tectonic plates that cause the fault lines, we recommend the map from MyReadingMapped that we reviewed here.
We have also looked at the aftermaths of earthquakes, such as the August 2014 Napa Earthquake.
The post California fault lines and earthquake probabilities appeared first on Google Earth Blog.
While looking around Cape Town, South Africa in Google Earth recently, we noticed a 3D model of a large South African flag on Devil’s Peak. It is the old type of 3D model from the Sketchup 3D warehouse. It looks like Google’s quality checks missed it when it got added. There is actually no flag at that location, or at least not of that size. We measured it using Google Earth Pro’s measuring tools at approximately 123m tall. Although flags have been temporarily erected by hikers at that location in the past, as can be seen in the last image in this blog post, there is no permanent flag there. Also of interest is that the model was uploaded to the 3D warehouse on September 28th, 2013, just a few days before Google stopped accepting models from the 3D warehouse.
The flag on Devil’s Peak, Cape Town.
This is not the first 3D model to have incorrectly got into Google’s 3D buildings layer. Back in 2009, for example, a model of the Burj Dubai (later renamed the Burj Khalifa) was incorrectly placed in Melbourne, Australia. There are a few other models that do not reflect reality, but can be considered Easter Eggs rather than mistakes. These include the Blues Brothers Bridge Jump and the Tardis. The Tardis even includes Street View inside it, although it doesn’t seem to be possible to view it using Google Earth. Both these locations now have Google’s new 3D mesh, but if you switch to historical imagery, they can still be seen.
The Blues Brothers Bridge Jump
To find these locations in Google Earth download this KML file.
Ever since Google Earth was first released, users have been spotting aircraft in flight in the imagery.
When an aircraft is captured in flight in Google Earth it is not uncommon for it to have a second ghostly image next to it, or in some cases a rainbow effect. This is caused by the way satellite cameras are designed. Satellites have multiple cameras for capturing imagery in different wavelengths of light. A common setup is to have a high resolution monochrome camera and then a separate camera that takes photos with various colour filters in quick succession. The multiple images are then combined to form what you see in Google Earth. However, if there is a fast moving object in the scene such as an aircraft, it will have moved between exposures and the ghosting or rainbow effects can be seen, depending on what type of camera the satellite is using. In addition to the aircraft’s movement, the satellite itself is moving and due to parallax the aircraft will appear to have moved in relation to the ground. This often results in the multiple images being offset from the direction the aircraft is travelling in.
The satellite took images in quick succession with blue, green then red colour filters, and finally a higher resolution image in monochrome.
In this image, the satellite took the high resolution monochrome image first, and then red, green and blue colour filters. We don’t know how the double image of the aircraft tail happened.
This image shows an aircraft and its shadow both exhibiting ghosting.
Satellites are also capable of taking images in spectral ranges far outside the visible range such as in the infrared. These images have a variety of uses including mineral exploration, environmental monitoring, agriculture and military. Digital Globe’s World View 3 that was launched last year and whose imagery we recently looked at shows on its datasheet that it is capable of capturing a variety of bands in the infra-red range.
To find the aircraft featured in this post, download this KML file.
When you place a 3D model in Google Google Earth you can use KML to decide how close the viewer has to be in order for it to be visible. For technical details on how this works and how to implement it see the KML documentation. This effect doesn’t just apply to 3D models but works for other KML features, such as placemarks and polygons. Google Earth Pro uses this concept for the regionation tool we looked at last month.
Today we are looking at how a similar effect is used by Google Earth to display its 3D imagery. As you fly around in Google Earth, you will notice that the 3D imagery fades out in the distance. However, if you actually measure the distance that it fades out, it varies considerably from location to location. It also varies depending on what screen size you are viewing Google Earth at. At full screen we found that for parts of New York, the limit is about 8km, whereas in Tokyo it is up to 30km.
Clearly, Google sets the maximum view distance for each piece of 3D imagery and they are not consistent. In fact, in New York there is a curious effect where you can sometimes see more distant imagery but not the imagery in the mid-field.
Presumably the reason for implementing the maximum view distance is to avoid possible issues with too much 3D being displayed at once. However, we believe that the maximum distance displayed could safely be increased quite a lot and we hope Google will consider increasing it.
In the above view of New York the old type of 3D buildings (1) from the Sketchup 3D warehouse can be seen at great distances, far exceeding that of the automatically generated 3D. The bridge in the distance (2) and the neighbouring buildings become visible before some of the nearer 3D imagery (3) next to Central Park.
We recently noticed that if you look at a given place in both Google Earth and Google Maps’ ‘Earth’ view, they look a bit different, with distant objects looking closer in Google Maps than in Google Earth. The main reason for this is that Google Earth by default has a different Field of View from Google Maps.
Last year we showed you how to change the field of view in Google Earth using a tour KML. After some experimentation we reckon that Google Earth by default uses a horizontal field of view (HFOV) of about 60° and Google Maps uses a HFOV of about 35° for its ‘Earth’ view.
So to match up a given location you need to download this KML file, which adjusts Google Earth’s HFOV to 35 degrees. In addition, you may want to try turning on ‘Photorealistic Atmosphere’ in Google Earth’s settings to get the colours to match up a bit better.
Praia Grande, Brazil, with Google Earth’s default settings. Note how the marked building and hill in the distance look further away than in the Google Maps screen shot below.
Praia Grande, Brazil, in Google Maps’ ‘Earth’ view.
Praia Grande, Brazil, in Google Earth with an HFOV of 35° and ‘Photorealistic Atmosphere’.