I’ve added a new page (in the menu on the left) to index my GE browser Plug-in projects, with three more examples to go alongside the flight simulator game and bounce! animation.
Delving into the API…
- A basic Polygon Editor. Something I plan to develop further. Use draggable pushpins to rotate, re-size and locate a single, regular polygon or circle anywhere on the globe, then export the result as a KML file. An info panel populates with values for circumference, area, radius and bearing in real time.
And a couple hooking into some of my pre-existing KML files:
- Mouseover Flight Route Maps for three European low-cost airlines: Easyjet, Ryanair and Wizzair. The information in these is several months out of date so don’t rely on it being accurate.
- A view based Hertszprung-Russell Diagram – a scatter plot of stars’ luminosity vs colour – for Sky mode (obviously). Which includes 3000 nearby stars from the Hipparcos catalogue. Built around an unusual KML hack, which I’ll write about another time.
A couple of weeks ago I put together a small collection of Google Earth airline route maps for various countries. These work interactively, using mouse hovers over airport Icons to activate and reveal destinations.
The previous files each had fewer than a thousand routes, and were fairly limited in scope. So, I was wondering, how effectively do these scale up ? As it turns out, surprisingly well.
The following Google Earth networklink opens a file including 13287 scheduled routes within the USA, between 714 airports.
Flight Maps (USA) (2 MB)
Data is from the US Bureau of Transportation’s most recent monthly flight stats: October 2007. Strictly speaking it’s not really a route map in the same way as my other files – rather, it’s a map showing where scheduled airlines flew that particular month.
- Because of the high number of placemarks and long distances involved, this all looks much better full screen [F11].
- To permanently lock on a set of lines:
- Right click on the entire file, a folder or airport,
- Go to Properties,
- Select the Style, Color tab,
- Then increase the line opacity.
- Hit OK.
- The only way to fully reverse this, and get the mouse over effect back, is to re-download or re-open the file. To do this within GE: right-click on the root folder: US Flight Maps, and select refresh.
- Don’t forget you can hold down the middle mouse button and swing the view around while keeping the flightpaths displayed.
Where are the busiest commercial passenger airports in the USA, and how are they distributed across the country ?
This Google Earth KML file mashes up a geographic database of FAA (Federal Aviation Authority) airport codes, with passenger boarding totals (enplanements) for the year 2006.
Download the file here:
2200 Airports (USA) (150kB)
Icon dots are scaled in size according to number of passengers, Atlanta-Hartsfield being the biggest. Similarly, the colours run through dark blue to red – Atlanta the reddest.
- Hover the mouse over each dot to see the passenger totals and airport name.
- Double click an Icon for information on where it ranks amongst the list of the busiest, and how the stats break down into scheduled and unscheduled boardings.
- Navigate up and down the league table using the arrows either side of the ranking position.
- Restrict the range of airports shown by turning off folders in the left sidepanel.
Note: There’s a chance GE might slow down some older machines with this file open – I think it’s worthwhile seeing all the information on screen at once with this one, no attempt to dynamically limited which parts of the KML are shown at any one time (Regions)
Here’s a couple more of these Google Earth, Interactive Flight Route Maps. Australia, including 171 airports, and 875 scheduled domestic routes. And one for New Zealand with 36 airports and 193 flight paths.
New Zealand Flight Map (50kB)
Australia Flight Map (300kB)
These operate on exactly the same principle as the flight map for the UK and Ireland. Simply open the file with Google Earth, and roll the mouse over an airport to see all the routes from it appear on the map. Click on an airport icon for more details.
All the airport destination data for this is sourced from Wikipedia, so don’t rely on it being 100% accurate.
I made a handful of modfications to these compared with the previous visualization:
- Flight profiles differ in heights according to their length. The longer the route the higher it is.
- There’s extra information in the pop-up balloons: Airport names, ICAO codes, IATA codes, and links to the source Wikipedia articles.
- Yellow Icons indicate airports for which Wikipedia doesn’t yet have a flight destination list. My script fills in the missing information for these by scanning through all the outbound destinations from other airports and assuming the same airline flies back to where it came from. In some cases, e.g. circuit routes, this will throw up false information.
Since I put together the Google Earth animated flights from USA airports (more of those coming up soon!), I’ve been meaning to check out the same thing without the time element – a KML file where routes only display as you hover the mouse over various airports. Essentially a Google Earth, 3D equivalent of those interactive flight maps you see on airlines’ websites.
As a side effect it does create some navigation difficulties, but I still think it makes a lot of sense to de-clutter the screen, without forcing the user through a series of menus or pop-ups. More importantly, the effect is actually fairly straightforward to achieve using KML’s <StyleMap> entity. (Check this out for a good description of how it works.)
So, what I’ve done is applied mouseover effects to a (near) complete route map of scheduled flights within the UK, Ireland, Channel Islands and Isle of Man. That’s about 800 one-way routes, between 69 airports. Download the file here:
UK and Ireland Flight Map(250kB)
- The Placemark balloons include information about airlines and destinations.
- Labels follow Wikipedia’s convention of using place names rather than real airport names.
- Routes are displayed with exaggerated altitude. Still need to do a bit of work to get the balance of these right: check out some of the hair raising journeys between the Orkney Islands (NE Scotland). 🙂
One downside of GE’s highlight mode is it doesn’t stay switched on a after a mouse click. However, there are a few navigation tricks that allow you to keep routes displayed and move around …
- Click the middle mouse button on an airport icon, and hold it down while moving the the mouse.
- Hover the mouse pointer over an icon, then switch to keyboard control (cursor keys, shift + cursor keys, Page up/down, + key, – key, etc…).
- Click on an airport icon, quickly drag it and let go. Just as you would to set the Earth rotating.
The source data for all this is scraped from the Airport pages on Wikipedia, and compiled using a lot of Perl scripting to scrape, mash and meld it into KML. Obviously its never going to be 100% reliable, but at least it should be pretty easy to keep the file regularly updated, and expand to other parts of the world.