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SF.net SVN: matplotlib: [4992] trunk/toolkits/basemap
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From: <js...@us...> - 2008-03-04 21:59:47
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Revision: 4992
http://matplotlib.svn.sourceforge.net/matplotlib/?rev=4992&view=rev
Author: jswhit
Date: 2008-03-04 13:59:45 -0800 (Tue, 04 Mar 2008)
Log Message:
-----------
added drawmapscale method.
Modified Paths:
--------------
trunk/toolkits/basemap/Changelog
trunk/toolkits/basemap/README
trunk/toolkits/basemap/lib/mpl_toolkits/basemap/basemap.py
Modified: trunk/toolkits/basemap/Changelog
===================================================================
--- trunk/toolkits/basemap/Changelog 2008-02-29 14:04:48 UTC (rev 4991)
+++ trunk/toolkits/basemap/Changelog 2008-03-04 21:59:45 UTC (rev 4992)
@@ -1,4 +1,6 @@
version 0.99
+ * added drawmapscale method to create a map scale bar similar
+ to that available with the GMT's psbasemap.
* Now lives in mpl_toolkits.basemap. Instead
of 'from matplotlib.toolkits.basemap import Basemap',
use 'from mpl_toolkits.basemap import Basemap'.
Modified: trunk/toolkits/basemap/README
===================================================================
--- trunk/toolkits/basemap/README 2008-02-29 14:04:48 UTC (rev 4991)
+++ trunk/toolkits/basemap/README 2008-03-04 21:59:45 UTC (rev 4992)
@@ -114,5 +114,6 @@
Scott Sinclair
Ivan Lima
Erik Andersen
+Michael Hearne
for valuable contributions.
Modified: trunk/toolkits/basemap/lib/mpl_toolkits/basemap/basemap.py
===================================================================
--- trunk/toolkits/basemap/lib/mpl_toolkits/basemap/basemap.py 2008-02-29 14:04:48 UTC (rev 4991)
+++ trunk/toolkits/basemap/lib/mpl_toolkits/basemap/basemap.py 2008-03-04 21:59:45 UTC (rev 4992)
@@ -2768,6 +2768,176 @@
im = self.imshow(self._bm_rgba,ax=ax)
return im
+ def drawmapscale(self,lon,lat,lon0,lat0,length,barstyle='simple',\
+ units='km',fontsize=9,yoffset=None,labelstyle='simple',\
+ fontcolor='k',fillcolor1='w',fillcolor2='k',ax=None):
+ """
+ draw a map scale at lon,lat representing distance in the map
+ projection coordinates at lon0,lat0. The length of the scale
+ is specified by the length argument, with units given by the units
+ keyword (default 'km'). Two styles of scale bar are available
+ (specified by the labelstyle keyword) - 'simple' and 'fancy', which
+ correspond roughly to the corresponding styles provided by
+ the Generic Mapping Tools software. Default is 'simple'.
+
+ The fontsize and color of the map scale annotations can be specified
+ with the fontsize (default 9) and fontcolor (default black) keywords.
+
+ labelstyle='simple' results in basic annotation (the units on top
+ of the scalebar and the distance below). This is the default.
+ If labelstyle='fancy' the map scale factor (ratio between
+ the actual distance and map projection distance at lon0,lat0) and
+ the value of lon0,lat0 are also printed on top of the scale bar.
+
+ yoffset controls how tall the scale bar is, and how far the annotations
+ are offset from the scale bar. Default is 0.02 times the height of the map
+ (0.02*(self.ymax-self.ymin)).
+
+ fillcolor1 and fillcolor2 are only relevant for the 'fancy' scale bar.
+ They are the colors of the alternating filled regions (default white
+ and black).
+ """
+ # get current axes instance (if none specified).
+ if ax is None and self.ax is None:
+ try:
+ ax = pylab.gca()
+ except:
+ import pylab
+ ax = pylab.gca()
+ elif ax is None and self.ax is not None:
+ ax = self.ax
+ # not valid for cylindrical projection
+ if self.projection == 'cyl':
+ raise ValueError("cannot draw map scale for projection='cyl'")
+ # convert length to meters
+ if units == 'km':
+ lenlab = length
+ length = length*1000
+ elif units == 'mi':
+ lenlab = length
+ length = length*1609.344
+ elif units == 'nmi':
+ lenlab = length
+ length = length*1852
+ else:
+ msg = "units must be 'km' (kilometers), "\
+ "'mi' (miles) or 'nmi' (nautical miles)"
+ raise KeyError(msg)
+ # reference point and center of scale.
+ x0,y0 = self(lon0,lat0)
+ xc,yc = self(lon,lat)
+ # make sure lon_0 between -180 and 180
+ lon_0 = ((lon0+360) % 360) - 360
+ if lat0>0:
+ if lon>0:
+ lonlatstr = u'%g\N{DEGREE SIGN}N, %g\N{DEGREE SIGN}E' % (lat0,lon_0)
+ elif lon<0:
+ lonlatstr = u'%g\N{DEGREE SIGN}N, %g\N{DEGREE SIGN}W' % (lat0,lon_0)
+ else:
+ lonlatstr = u'%g\N{DEGREE SIGN}, %g\N{DEGREE SIGN}W' % (lat0,lon_0)
+ else:
+ if lon>0:
+ lonlatstr = u'%g\N{DEGREE SIGN}S, %g\N{DEGREE SIGN}E' % (lat0,lon_0)
+ elif lon<0:
+ lonlatstr = u'%g\N{DEGREE SIGN}S, %g\N{DEGREE SIGN}W' % (lat0,lon_0)
+ else:
+ lonlatstr = u'%g\N{DEGREE SIGN}S, %g\N{DEGREE SIGN}' % (lat0,lon_0)
+ # left edge of scale
+ lon1,lat1 = self(x0-length/2,y0,inverse=True)
+ x1,y1 = self(lon1,lat1)
+ # right edge of scale
+ lon4,lat4 = self(x0+length/2,y0,inverse=True)
+ x4,y4 = self(lon4,lat4)
+ x1 = x1-x0+xc; y1 = y1-y0+yc
+ x4 = x4-x0+xc; y4 = y4-y0+yc
+ if x1 > 1.e20 or x4 > 1.e20 or y1 > 1.e20 or y4 > 1.e20:
+ raise ValueError("scale bar positioned outside projection limb")
+ # scale factor for true distance
+ gc = pyproj.Geod(a=self.rmajor,b=self.rminor)
+ az12,az21,dist = gc.inv(lon1,lat1,lon4,lat4)
+ scalefact = dist/length
+ # label to put on top of scale bar.
+ if labelstyle=='simple':
+ labelstr = units
+ elif labelstyle == 'fancy':
+ labelstr = units+" (scale factor %4.2f at %s)"%(scalefact,lonlatstr)
+ else:
+ raise KeyError("labelstyle must be 'simple' or 'fancy'")
+ # default y offset is 2 percent of map height.
+ if yoffset is None: yoffset = 0.02*(self.ymax-self.ymin)
+ # 'fancy' style
+ if barstyle == 'fancy':
+ #we need 5 sets of x coordinates (in map units)
+ #quarter scale
+ lon2,lat2 = self(x0-length/4,y0,inverse=True)
+ x2,y2 = self(lon2,lat2)
+ x2 = x2-x0+xc; y2 = y2-y0+yc
+ #three quarter scale
+ lon3,lat3 = self(x0+length/4,y0,inverse=True)
+ x3,y3 = self(lon3,lat3)
+ x3 = x3-x0+xc; y3 = y3-y0+yc
+ #plot top line
+ ytop = yc+yoffset/2
+ ybottom = yc-yoffset/2
+ ytick = ybottom - yoffset/2
+ ytext = ytick - yoffset/2
+ self.plot([x1,x4],[ytop,ytop],color=fontcolor)
+ #plot bottom line
+ self.plot([x1,x4],[ybottom,ybottom],color=fontcolor)
+ #plot left edge
+ self.plot([x1,x1],[ybottom,ytop],color=fontcolor)
+ #plot right edge
+ self.plot([x4,x4],[ybottom,ytop],color=fontcolor)
+ #make a filled black box from left edge to 1/4 way across
+ ax.fill([x1,x2,x2,x1,x1],[ytop,ytop,ybottom,ybottom,ytop],\
+ ec=fontcolor,fc=fillcolor1)
+ #make a filled white box from 1/4 way across to 1/2 way across
+ ax.fill([x2,xc,xc,x2,x2],[ytop,ytop,ybottom,ybottom,ytop],\
+ ec=fontcolor,fc=fillcolor2)
+ #make a filled white box from 1/2 way across to 3/4 way across
+ ax.fill([xc,x3,x3,xc,xc],[ytop,ytop,ybottom,ybottom,ytop],\
+ ec=fontcolor,fc=fillcolor1)
+ #make a filled white box from 3/4 way across to end
+ ax.fill([x3,x4,x4,x3,x3],[ytop,ytop,ybottom,ybottom,ytop],\
+ ec=fontcolor,fc=fillcolor2)
+ #plot 3 tick marks at left edge, center, and right edge
+ self.plot([x1,x1],[ytick,ybottom],color=fontcolor)
+ self.plot([xc,xc],[ytick,ybottom],color=fontcolor)
+ self.plot([x4,x4],[ytick,ybottom],color=fontcolor)
+ #label 3 tick marks
+ ax.text(x1,ytext,'%d' % (0),\
+ horizontalalignment='center',\
+ verticalalignment='top',\
+ fontsize=fontsize,color=fontcolor)
+ ax.text(xc,ytext,'%d' % (0.5*lenlab),\
+ horizontalalignment='center',\
+ verticalalignment='top',\
+ fontsize=fontsize,color=fontcolor)
+ ax.text(x4,ytext,'%d' % (lenlab),\
+ horizontalalignment='center',\
+ verticalalignment='top',\
+ fontsize=fontsize,color=fontcolor)
+ #put units, scale factor on top
+ ax.text(xc,ytop+yoffset/2,labelstr,\
+ horizontalalignment='center',\
+ verticalalignment='bottom',\
+ fontsize=fontsize,color=fontcolor)
+ # 'simple' style
+ elif barstyle == 'simple':
+ self.plot([x1,x4],[yc,yc],color=fontcolor)
+ self.plot([x1,x1],[yc-yoffset,yc+yoffset],color=fontcolor)
+ self.plot([x4,x4],[yc-yoffset,yc+yoffset],color=fontcolor)
+ ax.text(xc,yc-yoffset,'%d' % lenlab,\
+ verticalalignment='top',horizontalalignment='center',\
+ fontsize=fontsize,color=fontcolor)
+ #put units, scale factor on top
+ ax.text(xc,yc+yoffset,labelstr,\
+ horizontalalignment='center',\
+ verticalalignment='bottom',\
+ fontsize=fontsize,color=fontcolor)
+ else:
+ raise KeyError("barstyle must be 'simple' or 'fancy'")
+
### End of Basemap class
def _searchlist(a,x):
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