On Nov 8, 2008, at 7:52 PM, acardh wrote: > Hi, > Plotting an sphere is straightforward but I need help in how to draw > points on the sphere. The sphere will represent the Earth and the > points will be some geo-coordinates . > > Thanks!!!
This depends on how your points are given. I'm going to assume you have latitude/longitude (in degrees), called phi and theta respectively. Then one would draw the sphere via sage: world = sphere((0,0,0), radius=1, color='blue') Here I'm making 100 random cities. sage: cities = [(ZZ.random_element(-180,180), ZZ.random_element (-90,90)) for _ in range(100)] Now I'll convert polar coordinates to regular xyz coordinates. sage: t = RDF(pi/180) sage: city_coords = [(cos(t*theta)*cos(t*phi), sin(t*theta)*cos (t*phi), sin(t*phi)) for theta, phi in cities] Now I'll plot them sage: world + sum([point3d(v, color='red') for v in city_coords]) I could have, of course, done something more interesting than "points" sage: world + sum([tetrahedron(size=.1, color='yellow').translate(v) for v in city_coords]) - Robert --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
