Wednesday, October 20, 2010

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.

No comments: