I agree that it would be useful, but basemap doesn't support EPSG codes, so this isn't fully possible in general.
On a side note, if you're ever just wanting to transform coordinates, pyproj supports generic proj4 strings. (e.g. "proj = pyproj.Proj(your_proj4_string)") It might be possible to initialize a projection in Cartopy from a generic pyproj projection... I'm not sure, though. At any rate, that doesn't answer your question at all, but consider it food for thought. Cheers, -Joe On Fri, Nov 7, 2014 at 7:16 AM, Knut-Frode Dagestad < knutfrodesop...@hotmail.com> wrote: > As an example, say I have a proj4 string defining a spatial reference > system: > p4 = '+lon_0=0.0 +lat_ts=60.0 +R=6370997.0 +proj=stere +x_0=-0.0 +units=m > +y_0=4327039.11059 +lat_0=90.0' > > Then one can construct a Basemap from this as: > map = Basemap(projection='stere', lon_0=0., lat_0=90, lat_ts=60, > llcrnrlat=50, urcrnrlat=70, llcrnrlon=0, urcrnrlon=20) > > > I could make a function to construct Basemap arguments from any user > specified proj4 string (which is out of control of my application). But > that function would probably be long and contain a lot of > projection-specific if-then-switches. Copying proj4 arguments directly does > not work, e.g. if passing "x_0=0" Basemap complains that x_0 is an > unexpected argument. > The problem of making a long parser is not that this is tedious, but that > it is error prone and unstable e.g. with respect to future upgrades of > Basemap or proj4 libraries. > > So as Basemap obviously does have an algorithm to create a proj4 string > from its input arguments, I was hoping the reverse algorithm would also be > available somehow. E.g. it would be very useful to be able to initialise a > Basemap with: > > map = Basemap(proj4=p4, llcrnrlat=50, urcrnrlat=70, llcrnrlon=0, > urcrnrlon=20) > > Knut-Frode > > > ------------------------------ > Date: Wed, 5 Nov 2014 09:32:16 -0800 > > > I think some examples would help. Which proj4 string are you looking to > use? How are you currently constructing the map? > -p > > On Wed, Nov 5, 2014 at 7:53 AM, knutfrode <knutfrodesop...@hotmail.com> > wrote: > > Does anyone know if this is possible? > > > > > > -- > View this message in context: > http://matplotlib.1069221.n5.nabble.com/Basemap-from-proj4-string-tp43428p44290.html > Sent from the matplotlib - users mailing list archive at Nabble.com. > > > ------------------------------------------------------------------------------ > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > > > > > ------------------------------------------------------------------------------ > > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > >
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