Revision: 6705
http://matplotlib.svn.sourceforge.net/matplotlib/?rev=6705&view=rev
Author: jswhit
Date: 2008-12-28 16:07:10 +0000 (Sun, 28 Dec 2008)
Log Message:
-----------
simplify calculation of geostationary limb
Modified Paths:
--------------
trunk/toolkits/basemap/lib/mpl_toolkits/basemap/proj.py
Modified: trunk/toolkits/basemap/lib/mpl_toolkits/basemap/proj.py
===================================================================
--- trunk/toolkits/basemap/lib/mpl_toolkits/basemap/proj.py 2008-12-26
23:20:56 UTC (rev 6704)
+++ trunk/toolkits/basemap/lib/mpl_toolkits/basemap/proj.py 2008-12-28
16:07:10 UTC (rev 6705)
@@ -94,20 +94,21 @@
elif self.projection == 'geos':
self._proj4 = pyproj.Proj(projparams)
# find major and minor axes of ellipse defining map proj region.
- delta = 0.01
- lats = np.arange(0,90,delta)
- lon_0 = projparams['lon_0']
- lons = lon_0*np.ones(len(lats),'d')
- x, y = self._proj4(lons, lats)
- yi = (y > 1.e20).tolist()
- ny = yi.index(1)-1
- height = y[ny]
- lons = np.arange(lon_0,lon_0+90,delta)
- lats = np.zeros(len(lons),'d')
- x, y = self(lons, lats)
- xi = (x > 1.e20).tolist()
- nx = xi.index(1)-1
- width = x[nx]
+ # h is measured from surface of earth at equator.
+ h = projparams['h'] + self.rmajor
+ # latitude of horizon on central meridian
+ lonmax = 90.-(180./np.pi)*np.arcsin(self.rmajor/h)
+ # longitude of horizon on equator
+ latmax = 90.-(180./np.pi)*np.arcsin(self.rminor/h)
+ # truncate to nearest hundredth of a degree (to make sure
+ # they aren't slightly over the horizon)
+ latmax = int(100*latmax)/100.
+ lonmax = int(100*lonmax)/100.
+ # width and height of visible projection
+ P = pyproj.Proj(proj='geos',a=self.rmajor,\
+ b=self.rminor,lat_0=0,lon_0=0,h=projparams['h'])
+ x1,y1 = P(0.,latmax); x2,y2 = P(lonmax,0.)
+ width = x2; height = y1
self._height = height
self._width = width
if (llcrnrlon == -180 and llcrnrlat == -90 and
This was sent by the SourceForge.net collaborative development platform, the
world's largest Open Source development site.
------------------------------------------------------------------------------
_______________________________________________
Matplotlib-checkins mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/matplotlib-checkins
