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Google Earth Placemarks

(also includes Google Maps)

General Notes:

• Google Earth allows you to create "bookmarks for places," which are called Placemarks. This could be used to show the QuarkNet detector array, QuarkNet centers or participating schools (even those without a detector), to "visit" the LIGO sites, or to "visit" CERN or other interesting places.

• Placemarks can be saved in files (called .kml or .kmz files) and then distributed to others. It's very easy and intuitive in the GUI. Instructions we could crib from are at http://pirates.spy-hill.net/glossary/index.php?title=Google_Earth_placemark

• Placemarks files can be shared via the "Google Earth Community" at http://bbs.keyhole.com/ubb/ubbthreads.php/Cat/0/C/20

• For example, BOINC user "bjango" created a placemarks file showing the locations of a collection of BOINC participants. BOINC user "Raven" has recently taken over maintaining this file. You can download it from http://bbs.keyhole.com/ubb/showthreaded.php/Cat/0/Number/863082/ for viewing with Google Earth, or you can view it with Google Maps

• Another example of the use of placemarks is the Baseball e-Lab (I don't know if it's really an e-Lab but I called it that because I got the data from a remote source: Google Earth). You'll have to read down a little, but if you do you will find a .kmz file as an attachment.

• Placemarks files can also be viewed using Google Maps. One of the many reasons this is useful is because Google Earth won't work well with old graphics cards or a dial-up network connection, but Maps will. This makes it more accessible.

• Google Maps can export a map created on their web site as a .kmz file, for viewing in Google Earth. So it's easy to go both ways between Maps and Earth.

• Google Earth also has "Sky", which lets you turn the viewpoint up to the sky. This could be useful for LIGO for discussing potential sources of gravitational waves, or just for general Astronomy.

• Placemarks files can be used as a "layer" to show all the locations which share the same property, such as all the volcanos, or all the people participating in BOINC. In that case the icon for each placemark should be the same, perhaps with only minor variations (eg. for BOINC project developers and team leaders have different colored icons, but it's all the same otherwise).

• Placemarks files can be used for "tours" to visit a sequence of places in turn. Eric assembled such a tour for a talk he was preparing about Einstein@Home. A draft is available here.

• Placemarks can have a time-span associated with them, in which case they appear and disappear as a time slider is moved in Google Earth.

• The first release of a placemarks file for QuarkNet does not have to have all the bells and whistles. It can just show the positions of the detectors in the array, and then later we could add details about those detectors or the schools as we learn more about the format and the capabilties of Google Earth.

Ideas for Use

• Tom Loughran's students have begun to assemble a map of the cosmic ray detector array. See the project page for their use of that map, and the home page of their school-based research community wiki.
• See also the SJHSRC student-generated kml map of earthquakes detected at LIGO-Hanford, below; that map is also visible on the associated project page from the wiki. Note that the call-out boxes associated with each placemark include hyperlinks to wiki pages dedicated to each quake, including plots from Bluestone:

• Beth Marchant has created a map of high schools and QuarkNet centers for Kansas, Idaho, and greater Chicago

• Create a map showing just currently active detectors, and encourage schools to upload so as to get on the list.

• Allow uploads of a placemark file from a school, either with the geometry upload or as a separate thing. These would be added to a master list of detectors, replacing the default entry taken from the database. Students could create a custom placemark which includes something about the school, and perhaps a picture of the school, the detector, or the class (subject to restrictions on publishing pictures or names of students in a public venue).

• Add a time span to each detector, starting with the first geometry upload and ending 3-6 months after the last upload. Then one can view the changes in the array with time in Google Earth using the time slider.

• Animate a shower by creating a placemark for detection of a given event. Since showers happen in nanoseconds, rescale the time of the event so that the whole shower develops in a few seconds instead. (Could add animated paths from the detectors to the server in Chicago after the shower ends, representing the data upload.)

File Format

• The format of a placemarks file is rather simple. A .kmz file is a ZIP archive containing a file called doc.kml and a subdirectory called files. The doc.kml file contains the location data using an XML schema called KML. The files subdirectory contains image files for the icons for each placemark and possibly for use in the "description" part of the placemark, which can use HTML markup.

• The KML and KMZ formats are described at http://code.google.com/apis/kml/documentation/

• FeedValidator.org now validates KML documents: http://feedvalidator.org

• Eric has demonstrated that it is fairly straightforward to generate the doc.kml file from a database using the "Home Port" location set by some participants on Pirates@Home. The example at http://pirates.spy-hill.net/user_profile/placemarks.kml can be viewed in Google Earth, but has no image icons (so you get the default push-pin). I will add further features later.

• You can also view any placemarks file in Google Maps by specifying the URL as a query parameter, as in this example: http://maps.google.com/?q=http://pirates.spy-hill.net/download/placemarks/placemarks.kml This can be useful for testing the file format, in additino to the FeedValidator link above. Actually, you can also just enter the URL in the search box at http://maps.google.com

• The largest difficulty with creating that placemarks file was parsing the coordinates, because people entered them in a variety of different formats. Eric wrote a parsing function which seems to work for almost all cases, and he tested it with 200+ examples from an earlier dataset collected on Pirates@Home. It certainly seems to work for the most common coordinate formats. The most common entry error was leaving off a "W" or a minus sign in longitude; (several Canadians ended up in Siberia. Perhaps this is not a problem on QuarkNet if you have already verified the detector coordinates, but perhaps it will provide a cross-check when adding new detectors.

• There seems to be a problem where Google Maps is less forgiving than Google Earth with format errors in placemarks files, possibly due to bad HTML in the description field. Raven is investigating this further. Some details at http://pirates.spy-hill.net/forum_thread.php?id=760#5583 Using FeedValidator.org will help avoid such difficulties

-- Main.EricMyers - 25 May 2007
-- Main.EricMyers - 21 May 2008
-- Main.EricMyers - 28 May 2008