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Incorporating Google Maps and Google Earth into your Remote Sensing Applications
J. FreemantleOARS Technical Meeting,Dec 11, 2006
Outline
Overview of Google EarthSimple examples using keyhole markup language (kml)Using the Google Maps/Earth APISome community examplesQuestions?
Google Earth
Client/Server ApplicationFree for basic versionWorks on Windows (2000/XP), Mac OS 10.3.9, Linux
Google Earth Overview
Satellite and Airborne Imagery 1-3 years oldSpatial resolution in countryside < 15 m. Major US cities less than 1-2 feet (20-40 cm).Parts of Manhattan (Fulton Co.) 10 cm!
York University
Newmarket
Low vs high res. data (Aurora)
Toronto
New York City (20 cm)
New York City (10 cm)
10 and 20 cm images compared
Primary Data (roads etc)
Boundary Errors
Why Google?
Its free!!!Generally up to dateLarge user communityDeveloper/programmer friendlyEasy to learnPlatform independentIts cool!
Assumptions/Caveats
Check the fine print of End User License (EUL) for your situation.Google Earth 4.0 (Beta), free version.Public/Private data? (choose wisely).
Simple Examples using KML
PointPicturesTracksOverlaysLinks to external data
Warning Code Examples!
Keyhole Markup Language (kml)
Xml grammar and file format for describing geographic features in google earth/maps
PointsLinesPolygonsModelslinks
Keyhole Markup Language (KML)
KML files can be shared.KMZ files are a compressed version of KML files.Google Earth processes kml files like web browsers process html files.
Kml example: Simple point
<?xml version="1.0" encoding="UTF-8"?><kml xmlns="http://earth.google.com/kml/2.0"><Placemark> <name>OARS Meeting</name> <description><![CDATA[Incorporating Google Maps and Google Earth into your Remote Sensing Applications <br>Presented by Jim Freemantle <br>Dec 11, 2006 7:00 pm <br>Room 129 Chemistry Building, York University, Toronto. <br>]]></description> <Point id="khPoint616"> <coordinates>-79.508,43.773225,0</coordinates> </Point></Placemark></kml>
Simple Point
Simple Point
Simple point, with link
<?xml version="1.0" encoding="UTF-8"?><kml xmlns="http://earth.google.com/kml/2.0"><Placemark> <name>OARS Meeting</name> <description><![CDATA[Incorporating Google Maps and Google Earth into your Remote Sensing Applications <br><a href=“http://www.oars.on.ca/meetings.php”> details </a><br>]]></description> <Point id="khPoint616"> <coordinates>-79.508,43.773225,0</coordinates> </Point></Placemark></kml>
Simple point with link
Simple point, with image
<?xml version="1.0" encoding="UTF-8"?><kml xmlns="http://earth.google.com/kml/2.0"><Placemark> <name>OARS Meeting</name> <description><![CDATA[Incorporating Google Maps and Google Earth into your Remote Sensing Applications <br><a href=“http://www.oars.on.ca/meetings.php”> details </a><br><img src="c:/documents and settings/user/my documents/my pictures/jim_pic.jpg"/>]]></description> <Point id="khPoint616"> <coordinates>-79.508,43.773225,0</coordinates> </Point></Placemark></kml>
Simple point with image
Track<?xml version="1.0" encoding="UTF-8"?><kml xmlns="http://earth.google.com/kml/2.0"><Document> <name>t0490f13</name> <Placemark>
<name>t0490f13</name><description><![CDATA[Flight Line 13 tape 490 CASI 2001 <br>]]></description> <LineString><coordinates>-68.8911,48.79734,2470.74 -68.8947,48.79449,2471.35 </coordinates><coordinates> -68.9127, 48.78028,2466.96,-68.9164,48.77747,2469.82 </coordinates> </LineString> </Placemark></Document></kml>
Track
Track
GeoTagging
GeoTagging
RequirementsGPS device Camera with EXIF format jpg files and internal clockSoftware to sync gps track with time of photoSoftware to create google earth file (.kml)
GeoTagging
GPS Devices Used
Sony GPS-SC1 ($129.00)
Garmin Forerunner 201Runners GPS ($159.00)
GeoTagging
Software UsedGPSBabel (NMEA to GPX)GPS Image Tracker (Sony) (Not required)iTag
GeoTagging
GeoTagging
GeoTagging
Overlays
Getting your georeferenced data into Google Earth
Need georeferenced dataManually imported, as a jpg image, and matched to Google Earth
Overlays
Overlays
Links
ImagesExternal websites via urlDatabases
Track with link<?xml version="1.0" encoding="UTF-8"?><kml xmlns="http://earth.google.com/kml/2.0"><Document> <name>t0489f06</name> <Placemark>
<name>t0489f06</name><description><![CDATA[Flight Line 06 tape 489 CASI 2001 <br><a href="http://www.aerocan.net/tapedb.xml#489"> Link to Flight Log </a> <br>]]></description> <LineString><coordinates>-68.8911,48.79734,2470.74 -68.8947,48.79449,2471.35 </coordinates><coordinates> -68.9127, 48.78028,2466.96,-68.9164,48.77747,2469.82 </coordinates> </LineString> </Placemark></Document></kml>
Track with link
Point with link<?xml version="1.0" encoding="UTF-8"?><kml xmlns="http://earth.google.com/kml/2.0"><Placemark> <name>Waskesiu</name> <description><![CDATA[Aeronet Sites Worldwide<br><a href="http://aeronet.gsfc.nasa.gov/cgi-bin/ type_one_station_opera_v2_new?site=Waskesiu&nachal=2&aero_water=0&level=1 &if_day=0&year_or_month=0">Link to Waskesiu data</a><br>]]></description> <Point id="khPoint616"> <coordinates>-106.083,53.916698,550</coordinates> </Point></Placemark></kml>
Point with Link
Google Earth/Map Application Programmer Interface (API)
Sign up for your keyCan be used only on requested web accessible directory eg. http://www.example.com/gmapsReceive example script and put it in that directoryBuild Google Map applications from there
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"/> <title>Jim's Google Maps JavaScript API Example from M. Brown</title> <script src="http://maps.google.com/maps?file=api&v=2&key=xxx" type="text/javascript"></script> <script type="text/javascript">
//<![CDATA[ var largemapcontrol = new GLargeMapControl(); function load() { if (GBrowserIsCompatible()) { var map = new GMap(document.getElementById("map"));
GEvent.addListener(map,'click',function(overlay,point) { var latLngStr = '(' + point.x + ', '+ point.y + ')<br/>'; var message = document.getElementById("message");message.innerHTML = latLngStr;});
map.centerAndZoom(new GPoint(-79.505, 43.77382), 4); map.addControl(largemapcontrol); } } //]]>
</script> </head> <body onload="load()" onunload="GUnload()"> <div id="map" style="width: 500px; height: 300px"></div> <div id="message"></div> </body></html>
Google Map API
Google Earth API
Link to dynamically generated kmlNo API key required
See http://earth.google.com/kml/kml_tut.html#tracking_point
Google Earth Example<?php// get the time$timesnap = date("H:i:s");
$BOX=$_GET[BBOX];// split the client's BBOX return by commas and spaces to obtain an array of coordinates$coords = preg_split('/,|\s/', $BOX);
// for clarity, place each coordinate into a clearly marked bottom_left or top_right variable$bl_lon = $coords[0];$bl_lat = $coords[1];$tr_lon = $coords[2];$tr_lat = $coords[3];
// calculate the approx center of the view -- note that this is innaccurate if the user is not looking straight down$userlon = (($coords[2] - $coords[0])/2) + $coords[0];$userlat = (($coords[3] - $coords[1])/2) + $coords[1];
$response = '<?xml version="1.0" encoding="UTF-8"?>';$response .= '<kml xmlns="http://earth.google.com/kml/2.0">';$response .= '<Placemark>';$response .= '<name>'.$timesnap.'</name>';$response .= '<Point>';$response .= "<coordinates>$userlon,$userlat,0</coordinates>";$response .= '</Point>';$response .= '</Placemark>';$response .= '</kml>';echo $response;
?>
Examples from the Community
“Mashups”
Acknowledgements
Data providers J. Miller (York U), A. Smith (Agr. Canada)
Colleagues I. Lumb, L. Gray
Resources
http://earth.google.comhttp://maps.google.comhttp://www.oars.on.ca“Hacking Google Maps and Google Earth” by Martin C. BrownCheck back on the OARS website for a copy of these slides and list url of useful links
ResourcesInteresting linksGeoTagging "adding location information to pictures"
http://www.iceburnslair.com/mapper/http://wwmx.org/Download.aspxhttp://www.oziphototool.com//http://www.gpsbabel.org/http://itagsoftware.awswa.com/Interesting discussion at Canadian Canoe Routes on this topic:http://www.myccr.com/SectionForums/viewtopic.php?p=183038Mashups:http://www.beerhunter.ca/OttawaAreahttp://googlemapsmania.blogspot.com/
Questions?