ross.wil...@ga.gov.au wrote: > -----Original Message----- > <snip> > >> Maybe I'm just extra ignorant today, but why *shouldn't* a scale be drawn on >> a 'cyl' projection???? >> >> > <snip> > > Ross: Because a cylindrical projection isn't really a projection at all > - it's just a lat/lon coordinate system. > > -Jeff > > <snip> > -----Original Message----- > > Hi Jeff, > > Yes, surely, cylindrical isn't a real hairy-chested projection like Mercator, > et al, yet I can create a map with the 'Equidistant Cylindrical Projection' > and a scale has just as much meaning on a cylindrical 'projection' as any > other. > > That is, the semantics of the drawmapscale() method have meaning, even in > cyclindrical: "draw an annotation at this point representing the scale at > that other _point_". Yes, as you move away from the point the scale > annotation is representing the errors grow, but that is true of many > projections. True, the errors for cylindrical projections get rather large, > especially in the higher latitudes, but that just means the creator/user must > understand the limitations. > > Ross > Ross: You're right, I guess the real reason is that when you create a basemap instance with projection='cyl', then do
x,y = map(lon, lat) # map is a Basemap instance for projection='cyl' nothing happens - that is x,y are still longitudes and latitudes in degrees. So, there is nothing from which to compute a map scale, since no projection is happening. -Jeff -- Jeffrey S. Whitaker Phone : (303)497-6313 Meteorologist FAX : (303)497-6449 NOAA/OAR/PSD R/PSD1 Email : jeffrey.s.whita...@noaa.gov 325 Broadway Office : Skaggs Research Cntr 1D-113 Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
