X Slippy Maps. (...and Scott Davis)

Transcription

1 X Slippy Maps (...and Scott Davis) 1

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3 Scott Davis 3

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5 It was the best of times, it was the worst of times... 5

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7 Ajax 7

8 Static Maps vs. Slippy Maps 8

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11 Who is the OGC? The Open Geospatial Consortium The Open Geospatial Consortium, Inc. (OGC) is a non-profit, international, voluntary consensus standards organization that is leading the development of standards for geospatial and location based services. 11

12 Web Mapping Service (WMS) VERSION=1.1.1& REQUEST=GetMap& SRS=EPSG:4326& BBOX=-126,20,-66,52& WIDTH=500& HEIGHT=500& LAYERS=us_states_poly& STYLES=& FORMAT=image/png& BGCOLOR=0xffffff& TRANSPARENT=FALSE& EXCEPTIONS=application/vnd.ogc.se_inimage 12

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14 Composition The WMS spec predates Google Maps The intent is map composition, not slippy maps Each request is painstakingly assembled, lovingly rendered, and then thrown away 14

15 Decisions, Decisions Slippy Map Built for speed Many tiles Fixed zoom levels Fixed map layers Fixed image format WMS Built for customization One big tile Variable zoom levels Variable map layers Variable image format 15

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18 Tiled Tessellated Mosaicked 18

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22 Google Maps is one of many free APIs Others: Offers Ajax, Flash, and GeoRSS Microsoft s Offering 22

23 To begin, we need to sign up for a free Google Maps key 23

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25 Example Page 25

26 Here is our first map 26

27 Adjusting our lat/lon and zoom level: Zoom 0 == World Zoom 20 == Street Level function load() { if (GBrowserIsCompatible()) { var map = new GMap2(document.getElementById("map")); map.setcenter(new GLatLng( , ), 16); } } 27

28 Map, Round 2 28

29 Let s add in some controls: function load() { if (GBrowserIsCompatible()) { var map = new GMap2(document.getElementById("map")); map.setcenter(new GLatLng( , ), 16); map.addcontrol(new GLargeMapControl()) map.addcontrol(new GMapTypeControl()) } } 29

30 Map, Round 3 30

31 Finally, let s add a marker and an info window: var logourl = " images/header_logotype.gif" var bcdesc = "<img src='" + logourl + "' width='321' height='72'/>" bcdesc += "<br />" bcdesc += "<a href=' lasvegas/index.html'>" bcdesc += "TheServerSide, Java Symposium" bcdesc += "</a><br />" bcdesc += "Las Vegas, NV" bcmarker.openinfowindowhtml(bcdesc) 31

32 Map, Round 4 32

33 OpenLayers Pure JavaScript web client In addition to supporting OGC layers Google Maps Yahoo Maps MS Virtual Earth (Local Live) WorldWind 33

34 One Map 34

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37 Two Dimensional Maps vs. Three Dimensional Maps 37

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41 Google Earth is able to show all kinds of images overlaid on the surface of the earth and is also a Web Map Service (WMS) client. Google Earth supports managing threedimensional Geospatial data through Keyhole Markup Language (KML). 41

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43 Data vs Pretty Pixels Data services: WFS (Web Feature Service) Portrayal services: WMS (Web Mapping Service) 43

44 GetCapabilities The first thing a program will do is ask the OGC server what data layers it has to offer This is called a GetCapabilities request service=wfs& version=1.0.0& request=getcapabilities 44

45 GetCapabilities And here is the response: 45 45

46 DescribeFeatureType Once you find a layer that looks interesting, you can ask the service to describe it: version=1.0.0& service=wfs& request=describefeaturetype& typename=us_states_poly 46

47 DescribeFeatureType And here is the response: 47

48 GetFeature Finally, you can request the data layer: version=1.0.0& service=wfs& request=getfeature& typename=us_states_poly 48

49 GetFeature And here is the response: This is called GML (Geography Markup Language) 49 49

50 ( Astoundingly boring, isn't it?) 50

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57 [The 2009 JavaOne] Scriptbowl had 5 contenders: Jython, Groovy, Clojure, Scala and JRuby....via twitter: "Groovy won the Script Bowl at #javaone thanks to the griffon team for the demo". Here are a few snapshots of the demo: a mashup of NASA WorldWind and TwitterAPI, packaged as a Griffon application (Twittersphere): 57

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59 NeoGeography [This term] arose with the concept of Web 2.0, around the increased public appeal of mapping and geospatial technologies that occurred with the release of such tools as "slippy maps" such as Google Maps, Google Earth, and also with the decreased cost of geolocated mobile devices such as GPS units. 59

60 Ajax Maps vs. RIA Maps 60

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70 But wait -- there s more! 70

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73 But wait -- there s STILL more! 73

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77 So, what have we learned? 77

78 Desktop - Browser Deployment - Functionality Flex - Air 78

79 X Slippy Maps (...and Scott Davis) 79

80 Scott Davis Questions? Thanks for your time. 80