×

Like this presentation? Why not share!

Google Maps Projection, and how to use it for clustering

by lodeblomme on Nov 30, 2008

• 13,445 views

How Google presents the world with Google Maps, and what problems and opportunities that brings to developers. Offers an introduction to map projections and their consequences.

How Google presents the world with Google Maps, and what problems and opportunities that brings to developers. Offers an introduction to map projections and their consequences.

Views

Total Views
13,445
Views on SlideShare
13,398
Embed Views
47

Likes
5
154
0

5 Embeds47

 http://www.slideshare.net 37 http://faganm.com 7 http://www.fachak.com 1 https://blackboard.briarcliffschools.org 1 http://www.docshut.com 1

Google Maps Projection, and how to use it for clusteringPresentation Transcript

• Google Maps Projection And how to use it for clustering
• RouteYou  Products : • Community website: http://www.routeyou.com • Online recreational route planning • Maps for outdoor navigation for Garmin devices  Elevator Pitch : http://www.techcrunch.com/2008/10/24/elevator- pitch-friday-routeyou-makes-it-easy-to-find-the- perfect-driving-hiking-or-biking-route/
• Any method of representing the surface of a sphere on a plane MAP PROJECTION
• Map Projection  (pseudo)cylindrical  (pseudo)conical  azimuthal  hybrid
• Map projections can preserve one or more of the earth's properties, though not all of them simultaneously AREA SHAPE DIRECTION BEARING DISTANCE SCALE
• Lambert Conformal Conic Projection
• Cylindrical Projection
• Cylindrical Equal-Area Projection
• Mercator Projection
• Google Maps : Zoom Level 0 256 px 256 px
• Google Maps : Zoom Level 1 512 px
• Google Maps : Zoom Level 1
• Google Maps : Zoom Levels • 1 tile (2(0*2)) 256 x 256 pixels = 65 536 pixels 0 • 4 tiles (2(1*2))  512 x 512 pixels = 262 144 pixels 1 • 16 tiles (2(2*2))  1024 x 1024 pixels = 1 megapixel 2 ... • 17 179 869 184 tiles (2(17*2))  33.5 x 33.5 megapixels = 1 122 megapixels 17 ... • 274 877 906 944 tiles (2(19*2))  134 x 134 megapixels = 18 000 megapixels 19
• Assigning an n-tuple of numbers to each point in an n-dimensional space COORDINATE SYSTEMS
• Spherical Coordinate System
• Cartesian Coordinate System
• Everybody knows WGS 84 and pixels WGS 84  PIXELS
• Mercator Projection : The Math \$x = (\$radius * deg2rad(\$lon)) - \$falseEasting \$y = ((\$radius / 2.0 * log((1.0 + sin(deg2rad(\$lat))) / (1.0 - sin(deg2rad(\$lat))))) - \$falseNorthing) * -1
• Radius 256 px 256 px \$tiles = pow(2, \$zoom); \$circumference = 256 * \$tiles; \$radius = \$circumference / (2 * pi());