Visualizing Motion

Static and Dynamic Motion Viz: Timelines offer an excellent way to visualise motion of people or vehicles. I've discussed timelines in GEarth with a video illustration previously. Recently I've been hanging out at the GIS Stack forum which IMHO is an excellent resource. A recent question was on visualizing motion statically: what were the best techniques? What software could you use? I've pitched in with an answer along with some other contributors.

Static vs Dynamic: What doesn't come out in the discussion is would you choose a static option over the dynamic one if you had a choice? I think for the expert map reader (I'm thinking of a biologist tracking animal movement as an example) a static map has a number of advantages, it can be scanned quickly to find the point/time you are interested in and values of velocity are easy to read off. By comparison, an animation must be played to get to the point you want to view. As it can be printed it's also very portable.

For the bloke on the street, I think the dynamic version has most advantages: understanding the static version requires interpretation, the animation is instantly recognisable. Also, animations instantly attract the attention which is important for the public but not necessary for the expert.

Recording Tours via Screen Recorder

I've lots of deadlines coming in at the moment so excuse the lack of posts last week.

Prior to the appearance of the tour feature of Google Earth in v5 I discussed recording a tour by using screen recorder Fraps. Recently Google Earth Blog has discussed a smart variation on this idea: set the fly to rate very slow and then deliberately speed up the movie in a movie editing package (see Be Travellers post). This gets over a major problem of recording a movie with screen capture straight from GEarth: the resulting movie loses the smoothness and looks 'choppy' (the technical term is to say the frame rate is low). Smart idea!

Here's the video example:

The HowTo write up Mike Griffin does is good but I have some suggestions (numbers in brackets refer to their step numbers):

Dialog box in the way (1): The way to deal with this is to simply drag the dialog box so most of it is off screen. Its not particularly elegant but it solves the issue.

Setting Viewpoints with Placemarks (2): as I suggest in this tutorial, if you choose your viewpoint before you create a viewpoint placemark its better because GEarth automatically sets the current view as the Placemark's view.

Manual Flights Clicking (4): The main problem with the technique Mike suggests to my mind is that you have to sit there manually clicking placemarks and then watching as GEarth flies from placemark to placemark incredibly slowly. This would drive me nuts for anything but the shortest tour.

If you can handle XML an alternative is to dive into the KML you've produced in setting up the placemark viewpoints to grab the Camera or LookAt data (in italics below) for each placemark.

<Placemark id="ElkRidge">
<name>Elk Ridge</name>
<description>shortly after the eruption</description>
<Camera>
<longitude>-122.2989801778228</longitude>
<latitude>46.29626193853221</latitude>
<altitude>13.39603579634948</altitude>
<heading>-31.06642935444568</heading>
<tilt>90.62346382665406</tilt>
<roll>-6.361109362927034e-014</roll>
<altitudeMode>relativeToGround</altitudeMode>
<gx:altitudeMode>relativeToSeaFloor</gx:altitudeMode>
</Camera>
<styleUrl>#msn_grn-blank1</styleUrl>
<Point>
<coordinates>-122.2993707244499,46.2969626924056,0</coordinates>
</Point>
</Placemark>

You can insert this data from each placemark into a FlyTo construction in a tour:

<gx:FlyTo>
<gx:duration>3</gx:duration>
<gx:flyToMode>smooth</gx:flyToMode>
<Camera>
...same data as above in here...
</Camera>
</gx:FlyTo>

using a series of these will give you a tour and you can edit the duration tags to alter the speed of flight from placemark to placemark. When you're happy with how the tour looks you go back through the tour KML resetting each duration to be x10 what it was previously. Now you can set the screen recording going as Mike suggests, run your incredibly slow tour and let the computer do the work recording it while you go and have some lunch.

Other Advantages: Recording tours as videos rather than as tours in GEarth has other advantages: you can access all the features of the movie software you use (such as fade in transitions) which aren't available in Google Earth. As time goes on I expect Google will add more features to tours.

Maps and Art

There is an intriguing outbreak of using maps in art in the blogosphere;

The above image is of the English channel and is from the intriguing Fata Morgana which, using the latest feature in the Google Maps API has taken away everything but the words (and in the UK, what words! 'Hougham Without' in the middle of the image sounds lovely).

Axis maps release a set of posters working on a similar idea but putting a ton more cartographic love into their work.

Via Ogle Earth I found a wonderful reflective essay on the juxtaposition effects of imagery from different times: HiLoBrow.

And finally, Evert Schut finds inspiration in the many and varied patterns Google Earth produces at Google Earth Art.