1. Advanced KML
Bent Hagemark
May 29, 2008

2. Overview
OGC Standard
KML Architecture
Advanced features
Future enhancement

3. OGC Standard

4. OGC KML 2.2
April 14, 2008
Standard: 07-147r2
Abstract Test Suite: 07-134r2
100% quot;Googlequot; KML 2.2 compatible
xmlns=quot;http://www.opengis.net/kml/2.2quot;

5. OGC KML 2.2
www.opengeospatial.org/standards/kml
schemas.opengis.net/kml/2.2.0/ogckml22.xsd
code.google.com/apis/kml
code.google.com/apis/kml/documentation/kmlreference.html

6. KML Architecture

7. KML Architecture
Object
Feature
Geometry
Style
Link
Extension mechanism

8. Object
most complex elements
id=quot;IDquot;
targetId=quot;IDquot; for Update
AbstractXxxObjectExtensionGroup
kml:AbstractObjectGroup (8.1)

9. Feature
left panel entry: name, snippet, visibility
balloon
style
viewpoint, flyTo
custom data
kml:AbstractFeatureGroup (9.1)

10. Feature: concrete elements
Placemark
NetworkLink
Container: Document, Folder
Overlay: GroundOverlay, PhotoOverlay, ScreenOverlay

11. Geometry
2d or 3d
extrude
tessellate
kml:AbstractGeometryGroup (10.1)

12. Geometry: concrete elements
Point (icon)
LineString, LinearRing
Polygon
Model (textured 3d)
MultiGeometry

13. Style
shared style (6.4)
inline style
style resolution
kml:AbstractStyleSelectorGroup (12.1)

14. Style: concrete elements
Style
StyleMap
styleUrl
SubStyle: BalloonStyle, ListStyle, ColorStyle
ColorStyle: IconStyle, LabelStyle, LineStyle, PolyStyle

15. Link
href
network-shared style
network-shared schema
images, 3d models, more KML
balloon
ascription

16. Link: concrete elements
NetworkLink/Link/href
Overlay/Icon/href
Model/Link/href
styleUrl
schemaUrl
html:img src=quot;...quot;
html:a href=quot;...quot;
atom:link

17. Extension mechanism
ExtendedData/Data
Document/Schema, ExtendedData/SchemaData
ExtendedData/XML
XSD extension mechanism

18. XML and JavaScript
same model (same system!)
code.google.com/apis/kml/documentation
code.google.com/apis/earth

19. Advanced features

20. Review: Basic features
Placemark
Overlay
Folder
Style
NetworkLink

21. Advanced features
Region
Time
Update
ExtendedData

22. Region
Feature LOD
visibility transitions
millions of points
SuperOverlay

23. Region: any Feature
Placemark: visibility
NetworkLink: fetch
Overlay: fetch of image and visibility
Document/Folder: cascade

24. Region: simple effects
simple Lod
pop in and out
fade
clean swap with fade

25. Region: Example 1: simple Lod
<Placemark>
<Region>
<Lod>
<minLodPixels>128</minLodPixels>
</Lod>
<LatLonAltBox>...</LatLonAltBox>
</Region>
<Point>...</Point>
</Placemark>

26. Region: Example 2: pop in and out
<Placemark>
<Region>
<Lod>
<minLodPixels>128</minLodPixels>
<maxLodPixels>512</maxLodPixels>
</Lod>
<LatLonAltBox>...</LatLonAltBox>
</Region>
<Point>...</Point>
</Placemark>

27. Region: Example 3: clean swap
<Placemark id=quot;coarsequot;>
<Region>
<Lod> <!-- minLodPixels defaults to 0 -->
<maxLodPixels>256</maxLodPixels>
</Lod>
<LatLonAltBox>...</LatLonAltBox>
</Region>
<Point>...</Point> <!-- quot;come look herequot; -->
</Placemark>

28. Region: Example 3: clean swap
<Placemark id=quot;finequot;>
<Region>
<Lod>
<minLodPixels>256</minLodPixels>
</Lod> <!-- maxLodPixels defaults to -1 quot;infinitequot; -->
<LatLonAltBox>...</LatLonAltBox>
</Region>
<Polygon>...</Polygon> <!-- more detail -->
</Placemark>

29. Region: NetworkLink
<NetworkLink>
<Region>
<Lod>
<minLodPixels>256</minLodPixels>
</Lod>
<LatLonAltBox>...</LatLonAltBox>
</Region>
<Link>
<href>load-when-viewer-close-enough.kml</href>
<viewRefreshMode>onRegion</viewRefreshMode>
</Link>
</NetworkLink>

30. Region: quot;RbNLquot; and tools
cascade of Region-based NetworkLinks
KML Layers
code.google.com/p/regionator
csvregionator.py - CSV -> RbNL
placemarks.py - KML -> RbNL
checklinks.py - walks RbNL
checkregions.py - checks RbNL Regions
code.google.com/p/libkml

31. Region: quot;RbNLquot; Google Earth layers
Rumsey Historical Maps
Gigapan/Gigapxl Photos
YouTube
Books
News
Weather

32. Region: SuperOverlay
quot;RbNLquot; of GroundOverlays
Examples:
Google Earth Weather
disaster imagery

33. Region: tips and tricks
focus on Lod, especially minLodPixels
minLodPixels most likely > 128
Region with any Feature including ScreenOverlay
minLodPixels = 1/2 wid/ht of image tile
256x256 image -> minLodPixels 128
512 is 1/4 a typical screen

34. Time
Feature
TimeStamp
TimeSpan
Example: Google Earth Weather

35. Time: tips and tricks
TimeStamp for Points
TimeStamp: geographically non-coincident
TimeSpan for Overlays
TimeSpan: geographically coincident
Containers cascade
checkHideChildren

36. Update
Change
Create
Delete
Example: Santa

37. Update: Change
<!-- original fetched with NetworkLink -->
<kml xmlns=quot;www.opengis.net/kml/2.2quot;>
<Folder>
<Placemark id=quot;p1quot;>
<name>Point @ 3,-4.2</name>
<description>My movable Point</description>
<styleUrl>#some-style</styleUrl>
<Point>
<extrude>true</extrude>
<coordinates>3,4.2</coordinates>
</Point>
</Placemark>
</Folder>
</kml>

38. Update: Change
<kml><NetworkLinkControl>
<Update>
<Change>
<Placemark targetId=quot;p1quot;>
<name>Point @ 3,-4.2</name>
<Point>
<coordinates>3,4.2</coordinates>
</Point>
</Placemark>
</Change>
</Update>
</NetworkLinkControl>
</kml>

39. Update: NetworkLinkControl and cookie
<kml><NetworkLinkControl>
<!-- name=value compat with cgi parsing -->
<cookie>count=123</cookie>
<Update>
<Change>
<Placemark targetId=quot;p1quot;>
<Point>
<coordinates>[coords for 123]</coordinates>
</Point>
</Placemark>
</Change>
</Update>
</NetworkLinkControl></kml>

40. ExtendedData
Feature
Data: untyped data
Schema and SchemaData: typed data
quot;<xs:any>quot;: any XML
balloon templating with shared style
Example: Google Earth Weather
(Metadata deprecated)

41. ExtendedData: Example: Weather
<Placemark>
<name>...</name>
<styleUrl>http://.../style.kml#sunny</styleUrl>
<ExtendedData>...</ExtendedData>
<Point>...</Point>
</Placemark>

42. ExtendedData: Example: Weather
<!-- style.kml -->
<Style id=quot;sunnyquot;>
<IconStyle>
<Icon><href>sunny.jpg</href></Icon>
</IconStyle>
<LabelStyle>...</LabelStyle>
<BalloonStyle>
<text> <!-- 50 entities replaced in one template -->
...<td>$[01_Temperature]</td>...
</text>
</BalloonStyle>
</Style>

43. ExtendedData: Example: Weather
<ExtendedData>
<Data name=quot;locationquot;>
<value>Shillong, IN as of 2008-05-28 17:00</value>
</Data>
<Data name=quot;00_Temperaturequot;>
<value>80°F / 27°C</value>
</Data>
<Data name=quot;00_Phrasequot;>
<value>Haze</value>
</Data>
</ExtendedData>

44. ExtendedData: Example: weather
Feature
Data: untyped data
Schema and SchemaData: typed data
quot;<xs:any>quot;: any XML
balloon templating with shared style
Example: Google Earth Weather
(Metadata deprecated)

45. ExtendedData: tips and tricks
ExtendedData/Data
the comment trick

46. Future enhancement

47. Future enhancement
ExtendedData
XSD extension mechanism
OGC SWG

48. Demo

49. code.google.com/apis/kml