Table of Contents
Google Earth (GE) - Use for HAB purposes
There are a number of facilities within the UKHAS facilities that can make use of GE, the first is the link in the http://SpaceNear.Us/tracker the Habitat mobile tracker, from its help page “?” there is a link for displaying tracks in GE. This later facility also supports filtering, such as;
“mode” can take the values 1hour, 6hours, 1day, 3days, all
The second is from the Habitat database that allows the export of payload telemetry in KML format to be displayed in GE, see http://habitat.habhub.org/ept/
The third is using Google Earth to view predicted flight paths. See http://predict.habhub.org Run a flight prediction and click on KML that appears in the Scenario Information to download the predicted flight path in KML format.
Some users find the Navigation within GE confusing, so some tips and tricks to getting the best out of GE might assist.
One small handy utility is the following file;
Click the link and download or arrange your Browser to display the file using GE, once loaded into GE it will appear in the Temporary Places folder, drag it to the My Places folder above it and then save it using Files|Save|My Places. This will simply display a small white cross in the middle of the screen - the “Look At” point. You can tick the Box to display the cross or turn it off by unticking the box.
There are several other utilities that may be of interest as well here;
A further source of useful utilities is;
Navigating in GE
Before serious work can begin you need to understand that there are 3 sets of Navigation controls, each set is based on a sphere.
1. Using the 4 Arrow keys you can travel around a sphere centred on the middle of the Earth, the radius is controlled by the + and - keys, the status display shows the Height ASL and Lat & Long of your “Eye” above the Earth.
2. If you hold down the Shift key, and use the Arrow keys, then you travel around a Hemisphere based on the “Look At” point. However if you press any other keys during this operation then the rotation point will be lost and you will need to Reset.
3. If you hold down the Ctrl key, and use the Arrow keys, your direction of view can be controlled around the sphere based on your current “Eye” position shown on the Status line.
One other essential item to understand is that the height/Zoom keys + and - only work when the “Look At” point is touching the surface of the earth or an object, if its in the sky then you won't be able to change the setting! A couple of other handy short-cuts are the “R” key to reset your position, and the “N” key to set North at the top of the screen. Also pressing the “Alt” will slow down the movements for finer control.
Its worth having a play with the controls above to get used to them, especially the use of the Shift Key as this allows you to rotate around a point and view from all angles, good for inspecting a Flight path! A point to watch is that whe you use the Ctrl key the “Look At” point will move of course, if you then go to use the Shift controls you will spin around a totally different position…..
To grab a Screen image use Ctrl-Alt-S, the resolution will be that of your sceen.
How to load a Flight Path
From the http://spacenear.us/tracker site look in the lower right corner, you will see a link to “Track in Google Earth” or just use “http://spacenear.us/tracker/track.kml” all flights will be loaded and then refreshed on a 20 second interval. This can be altered if required by editing the “Tracker” properties. This can be handy when you want to move/copy a track from the tracker to “My Places” if your not careful an update will start just as you start to make the change and you will end up with an empty file!
If you don't have your data available in the form of a KML file then all is not lost, provided you can generate a simple text file consisting of Longitude, Latitude, Altitude one per line such as;
-1.02297,52.09585,77 -1.02261,52.09595,133 -1.02221,52.09558,61 -1.01351,52.09593,84 -1.00172,52.09605,250
Then all you need do is top your data with the following;
<?xml version="1.0" encoding="UTF-8"?> <kml xmlns="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2" xmlns:kml="http://www.opengis.net/kml/2.2" xmlns:atom="http://www.w3.org/2005/Atom"> <Document> <name>Demo-track.kml</name> <open>1</open> <Placemark> <name>Demo-track</name> <LineString> <extrude>1</extrude> <tessellate>1</tessellate> <altitudeMode>absolute</altitudeMode> <coordinates>
and tail your data with the following, to create a simple track;
</coordinates> </LineString> </Placemark> </Document> </kml>
Save the result as Track.kml and load this into GE to display your data. You can alter the way it is displayed in GE by editing the properties of the resulting track segment within GE once loaded, not forgetting to save the changes back to the file once altered of course!
Creating Object Movies
First what's an Object Movie ? Its an interactive sequence of images, that as you drag your mouse around on the image the view will change see http://360.g8dhe.net/hab_flights/PIE6/PIE6.html its a handy way of visualising the flight path and saves people having to load and navigate within Google Earth.
In addition to the images collected from GE, you will need some software to enable the images to be composed into the interactive sequence I use Object2VR from Garden Gnome software http://gardengnomesoftware.com/object2vr.php there are other packages about Google is your friend, but I am not aware of any free software as at May 2013.
Collecting images from GE for an Object Movie
Position the “Look At” cross on the ground track about half way between Launch and Landing spots of a flight path, you may want to turn the “wall” of vertical drop downs off depending on the path itself, use the Properties of the Track segment and the Altitude tab to change “Extend path to ground”. Choose a suitable elevation angle to show the path best and then starting from North, make screen grabs as you rotate in small steps around the path, about 20-40 steps is sufficient using the Shift and the Left arrow. Number the screen grabs as required and then load these images into the Object Movie software to create the sequence.
My own site at http://360.g8dhe.net/hab_flights has images, KML/Z files of flights, Object Movies and Pano's available for the flights I have managed to log and record.