Tech talk at Googleplex 12 December 2008

1. Using KML for Thematic Mapping Bjørn Sandvik thematicmapping.org MSc in Geographical Information Science University of Edinburgh Project Manager at United Nations Association of Norway Tech Talk at Googleplex 12 December 2008

3. Proportional symbols

4. Proportional symbols #1 Scaling image icons

10. Mathematical scaling of 2-D point symbols: symbolSize = power(value/maxValue; 1/2) * maxSize KML for proportional icon images <Style id='sharedStyle'> <IconStyle> <Icon> <href>files/symbol.png</href> </Icon> </IconStyle> <Style> KML <Placemark> <name>China</name> <Snippet>1,312,978,855 (2005)</Snippet> <styleUrl>#sharedStyle</styleUrl> <Style> <IconStyle> <color>e50066ff</color> <scale>7</scale> </IconStyle> </Style> <Point> <coordinates>106.514,33.42,0</coordinates> </Point> </Placemark> KML

11. Problem: Size affected by viewport

12. Not working in Google Maps

13. Proportional symbols #2 Drawing regular polygons

15. Problem: Complicated! function kmlSymbolCalculator ( $longitude, $latitude, $radius, $vertices) { $EARTH_RADIUS_EQUATOR = 6378140.0; $RADIAN = 180 / pi(); $long = $longitude / $RADIAN; $lat = $latitude / $RADIAN; $f = 1/298.257; $e = 0.08181922; $kml = '<Polygon><outerBoundaryIs><LinearRing><coordinates>'; for ( $bearing = 45; $bearing <= 405; $bearing += 360/$vertices ) { $b = $bearing / $RADIAN; $R = $EARTH_RADIUS_EQUATOR * (1 - $e * $e) / pow( (1 - $e*$e * pow(sin($lat),2)), 1.5); $psi = $distance/$R; $phi = pi()/2 - $lat; $arccos = cos($psi) * cos($phi) + sin($psi) * sin($phi) * cos($b); $latA = (pi()/2 - acos($arccos)) * $RADIAN; $arcsin = sin($b) * sin($psi) / sin($phi); $longA = ($long - asin($arcsin)) * $RADIAN; $kml .= &quot; “ . round($longA,$this->coordDecimals) . &quot;,“ . round($latA,$this->coordDecimals); } $kml = '</coordinates></LinearRing><outerBoundaryIs></Polygon>'; return $kml; }

16. Proportional symbols #3 Scaling 3-D Collada objects

19. Mathematical scaling of 3-D point symbols: symbolSize = power(value/maxValue; 1/3) * maxSize Making proportional Collada objects Position Measure / scale Colorize Google SketchUp <Placemark> <name>China</name> <Snippet>1,312,978,855 (2005)</Snippet> <Model> <Link> <href>files/object.dae</href> </Link> <altitudeMode>absolute</altitudeMode> <Location> <longitude>106.514</longitude> <latitude>33.42</latitude> <altitude>0</altitude> </Location> <Scale> <x>140000</x> <y>140000</y> <z>140000</z> </Scale> </Model> </Placemark> KML

20. Chart maps

24. Using Google Chart API in KML <Style id='sharedStyle'> <BalloonStyle> <text><![CDATA[ <img src='http://chart.apis.google.com/chart ?cht=p&chd=t:20,45,5 &amp;chd=t: $[chartValues] '> ]]></text> </BalloonStyle> </Style> KML <Placemark> <name>China</name> <Snippet>1,312,978,855 (2005)</Snippet> <styleUrl>#sharedStyle</styleUrl> <Style> <IconStyle> <scale>7</scale> <Icon> <href> http://chart.apis.google.com/chart?cht=p&chd=t:20,45,5&chs=300x150 &amp;chf=bg,s,ffffff00</href> </Icon> </IconStyle> </Style> <Point> <coordinates>106.514,33.42,0</coordinates> </Point> <ExtendedData> <Data name=&quot;chartValues&quot;> <value>20,45,5</value> </Data> </ExtendedData> </Placemark> KML

25. Choropleth maps

27. Prism maps

31. Problem: Polygon holes

32. KML used in prism maps Suggestion: <Placemark> <name>China</name> <Snippet>1,312,978,855 (2005)</Snippet> <styleUrl>#sharedStyle</styleUrl> <Style> <PolyStyle> <color>DC0066FF</color> </PolyStyle> </Style> <MultiGeometry> <Polygon> <extrude>1</extrude> <altitudeMode>absolute</altitudeMode> <outerBoundaryIs> <LinearRing> <coordinates> 110.72,20.06, 2000000 109.26,19.9, 2000000 108.63,19.28, 2000000 108.69,18.51, 2000000 110.05,18.38, 2000000 111.03,19.64, 2000000 (...) </coordinates> </LinearRing> </outerBoundaryIs> </Polygon> <Polygon> (...) </Polygon> </MultiGeometry> </Placemark> KML <Placemark> <name>China</name> <Snippet>1,312,978,855 (2005)</Snippet> <styleUrl>#sharedStyle</styleUrl> <Style> <PolyStyle> <color>DC0066FF</color> </PolyStyle> </Style> <MultiGeometry> <Polygon> <extrude>1</extrude> <altitude>2000000</altitude> <altitudeMode>clampToAltitude</altitudeMode> <outerBoundaryIs> <LinearRing> <coordinates> 110.72,20.06 109.26,19.9 108.63,19.28 108.69,18.51 110.05,18.38 111.03,19.64 (...) </coordinates> </LinearRing> </outerBoundaryIs> </Polygon> <Polygon> (...) </Polygon> </MultiGeometry> </Placemark> KML

33. 3-D bar maps

34. 3-D bars: One variable

35. 3-D bars: Two variables

36. Animated maps

38. Thematic Mapping Engine

39. Thematic mapping parameters Web Interface PHP Library Web Processing Service KML/KMZ Thematic Mapping Engine Thematic Mapping Engine

43. Apache MySQL PHP Web server HTML / JavaScript Ext JS Google Earth API Web browser 1. Get list of indicators 2. Get list of available years 3. Make KML/KMZ document 4. Download KML/KMZ file How it works

44. MySQL Data Connector Form Handler Database File Server Web server Web browser KML/KMZ files Web server infrastructure Thematic Mapping Engine

45. include ('TME_MySQL_DataConnector.php'); include ('TME_Engine.php'); $dataConnector = new DataConnector(); $dataStore = $dataConnector->getDataStore(68, 2005, 0); $parameters = array( 'mapType’ => 'choropleth', 'indicator' => 68, 'year' => 2005, 'classification' => 'equal' ); $map = new ThematicMap($dataStore, $parameters); $file = $map->getKML(); Application Programming Interface (API)

46. KML structure Add KML header Technique Choropleth Prism Bar Image Polygon Collada Type For each year For each feature Technique Choropleth Bar Image Polygon Collada Type Prism Add shared style Add shared style Add shared style Add shared style Colourise Collada object(s) Add style and feature Add style and feature Add style and feature Add style and feature Add style and feature Add link to Collada object Add map title and legend <Folder> <Placemark> </Placemark> </Folder> <kml> </kml> Symbol Symbol

47. Map legends Unclassed Equal intervals Quantiles

49. thematic mapping.org