Slides from my php geodata talk at DPC10.

1. Where in the World? Geo-data in PHP

2. 80% of data has a geo-component

3. Some background

4. Mercator - 1569

5. 51 28’ 38”N0 0’ 0” E Munich, 11E Paris, 2E Madrid, 3W Prime meridian Know your datum!

6. Points Paris 52°20'28N, 04°53'25E 12 Grimmauld Place, London What makes up geo-data?

7. Lines M4 Sunset Boulevard Dover TSS What makes up geo-data?

8. Polygons London Somerset Contour What makes up geo-data?

9. Is point x within y? Questions, questions…

10. Does line x pass through y? Questions, questions…

11. How far is point x from point y? Questions, questions…

12. Which region is point x within? Regions can overlap: District: ClaphamBorough: WandswothCity: LondonCountry: UK Questions, questions…

13. 80% of data has a geo-component So how do I find it?

14. Geo-data from web visitors

16. Ask the browser!Where is my visitor?

17. home 51 26’ 55.2” N 0 0’ 0.1” W exchange Accurate? IP gives you the location of the Serving area interface (telco exchange). Some exchanges can be 5 miles away! home office Reliable? Proxies VPNs Network distributions (ever tried geo-locating an AOL IP?) exchange The problem with IP

19. Pear extension

20. Apache moduleUse the code…

21. function myCallback(position) { // called if the browser reports its location } if (navigator.geolocation) {navigator.geolocation.getCurrentPosition(myCallback); } W3C spec:http://dev.w3.org/geo/api/spec-source.html Mozilla, where art thou?

22. Geo-data from content

23. “Journey’s End”by nathanhayag “MacRitchie Reservoir, Singapore” Geo-data encoded in the image file: 1°22'18”N103°49'27"E A picture says a thousand words

24. $exif = exif_read_data('file.jpg'); $long[‘deg’] = $exif['GPSLongitude'][0]; $long[‘min’] = $exif['GPSLongitude'][1] / 60; $long[‘sec’] = $exif['GPSLongitude'][2] / 3600; $lat[‘deg’] = $exif['GPSLatitude'][0]; $lat[‘min’] = $exif['GPSLatitude'][1] / 60; $lat[‘sec’] = $exif['GPSLatitude'][2] / 3600; Reading EXIF

25. “Journey’s End”by nathanhayag “MacRitchie Reservoir, Singapore” Parse text for location data…. Usual PHP information retrieval techniques apply http://phpir.com/ to learn more A picture says a thousand words

26. “Journey’s End”by nathanhayag “MacRitchie Reservoir, Singapore” Feeling brave? Image recognition and association A picture says a thousand words

27. External sources

28. Don’t forget…

29. Primitive data-types $long = 51.5723 $lat = -0.0179 Class structures $point = new GISPoint; $point->setLatitude(51,21,35,'N'); $point->setLongitude(0,1,21, 'W'); Geo-data in PHP variables

30. MySQL storage CREATE TABLE tweet( id BIGINT, user VARCHAR(15), message VARCHAR(140), location VARCHAR(16) ); INSERT INTO tweet VALUES ( 15924144610, 'manarth', 'hello!', '0512732N0000319W' ); Persistent storage

31. MySQL Spatial extensions CREATE TABLE tweet( id BIGINT, user VARCHAR(15), message VARCHAR(140), location POINT ); INSERT INTO tweet VALUES ( 15924144610, 'manarth', 'hello!', PointFromWKT(Point(51.1,-0.2)) ); Spatial extensions

32. MySQL MS SQL Oracle Postgres – PostGIS Geo-data in the DB

33. WKT: Well Known Text POINT(6 10) LINESTRING(3 4,10 50,20 25) WKB: Well Known Binary 1010010001001010 GeoJSON { "geometry": { "type" : "Point", "coordinates" : [97.03125, 39.7265625] } } Write to disk?

34. Binary Terrain Coverage (ArcGIS) DEM Spatial Data File (Autodesk) … More (obscure) formats

35. Discovery Storage Analysis

36. Geo-centric:Cartesian http://trac.osgeo.org/proj/wiki/man_cs2cs Coordinate conversion

37. Cartesian geometry a (x1, y1) √ (y1 – y2)2 + (x2 – x1)2 y1 – y2 b x2 – x1 (x2, y2) Distance from a to b

38. Geo-centric geometry Greater circle route a (λs, Φs) Haversine formula b (λf, Φf) Distance from a to b

39. function haversine($a) { return (sin($a/2) * sin($a/2)); } function ahaversine($a) { return 2 * asin(sqrt($a)); } function haversine_separation($a, $b) { // assume a radius of 3956 miles. define ('RADIUS', 3956); // convert degree inputs to radians $a = array(deg2rad($a['long']), deg2rad($a['lat'])); $b = array(deg2rad($b['long']), deg2rad($b['lat'])); $x = haversine($a['long'] - $b['long']) + (cos($a['long']) * cos($b['long']) * haversine(abs($a['lat'] - $b['lat']))); // $d (distance) is therefore R * inverse haversine($x) $d = RADIUS * ihaversine($x); return $d; } Haversine calculations

40. SELECT DISTANCE(a, b); SELECT INTERSECTS (a, b); SELECT DISJOINT (a, b); SELECT OVERLAPS (a, b); SELECT CONTAINS (a, b); SELECT WITHIN (a, b); Some limitations – currently measures against MBR – Minimum Bounding Rectangle Spatial analysis in MySQL

41. Discovery Storage Analysis Visualisation

42. Map APIs

43. Simple overlays

44. Heatmaps

45. Custom visualisation

46. Image generation

48. Ignite BristolBristol - July

49. DrupalconCopenhagen - August

51. PHP NWManchester - October

52. PHP BarcelonaBarcelona - October

53. ZendConSanta Clara - OctoberLoremipsum Loremipsum dolor sit amet, consecteturadipisicingelit, sed do eiusmodtemporincididuntutlabore et dolore magna aliqua. Utenim ad minim veniam, quisnostrud exercitation ullamcolaboris nisi utaliquip ex ea commodoconsequat. Duisauteirure dolor in reprehenderit in voluptatevelitessecillumdoloreeu fugiatnullapariatur. Excepteursintoccaecatcupidatat non proident, sunt in culpa qui officiadeseruntmollitanim id estlaborum Invisible feedback

54. Discovery Storage Analysis Visualisation

55. 80% of data has a geo-component

56. Marcus Deglos marcus@deglos.com http://deglos.com/ @manarth Thanks for coming! http://joind.in/1555