SF.net SVN: matplotlib:[7555] trunk/toolkits/basemap/examples

[<js...@us...>]

Revision: 7555
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=7555&view=rev
Author:   jswhit
Date:     2009-08-24 19:03:32 +0000 (Mon, 24 Aug 2009)

Log Message:
-----------
rename example

Added Paths:
-----------
    trunk/toolkits/basemap/examples/daynight.py

Removed Paths:
-------------
    trunk/toolkits/basemap/examples/terminator.py

Copied: trunk/toolkits/basemap/examples/daynight.py (from rev 7554, trunk/toolkits/basemap/examples/terminator.py)
===================================================================
--- trunk/toolkits/basemap/examples/daynight.py	                        (rev 0)
+++ trunk/toolkits/basemap/examples/daynight.py	2009-08-24 19:03:32 UTC (rev 7555)
@@ -0,0 +1,75 @@
+import numpy as np
+from mpl_toolkits.basemap import Basemap, netcdftime
+import matplotlib.pyplot as plt
+from datetime import datetime
+
+def epem(date):
+    """
+    input: date - datetime object (assumed UTC)
+    ouput: gha - Greenwich hour angle, the angle between the Greenwich
+           meridian and the meridian containing the subsolar point.
+           dec - solar declination.
+    """
+    dg2rad = np.pi/180.
+    rad2dg = 1./dg2rad
+    # compute julian day from UTC datetime object.
+    jday = netcdftime.JulianDayFromDate(date)
+    jd = np.floor(jday) # truncate to integer.
+    # utc hour.
+    ut = d.hour + d.minute/60. + d.second/3600.
+    # calculate number of centuries from J2000
+    t = (jd + (ut/24.) - 2451545.0) / 36525.
+    # mean longitude corrected for aberration
+    l = (280.460 + 36000.770 * t) % 360
+    # mean anomaly
+    g = 357.528 + 35999.050 * t
+    # ecliptic longitude
+    lm = l + 1.915 * np.sin(g*dg2rad) + 0.020 * np.sin(2*g*dg2rad)
+    # obliquity of the ecliptic
+    ep = 23.4393 - 0.01300 * t
+    # equation of time
+    eqtime = -1.915*np.sin(g*dg2rad) - 0.020*np.sin(2*g*dg2rad) \
+            + 2.466*np.sin(2*lm*dg2rad) - 0.053*np.sin(4*lm*dg2rad)
+    # Greenwich hour angle
+    gha = 15*ut - 180 + eqtime
+    # declination of sun
+    dec = np.arcsin(np.sin(ep*dg2rad) * np.sin(lm*dg2rad)) * rad2dg
+    return gha, dec
+
+def daynightgrid(date, nlons):
+    """
+    date is datetime object (assumed UTC).
+    nlons is # of longitudes used to compute terminator."""
+    nlats = ((nlons-1)/2)+1
+    dg2rad = np.pi/180.
+    lons = np.linspace(-180,180,nlons)
+    # compute greenwich hour angle and solar declination
+    # from datetime object (assumed UTC).
+    tau, dec = epem(date) 
+    longitude = lons + tau
+    lats = np.arctan(-np.cos(longitude*dg2rad)/np.tan(dec*dg2rad))/dg2rad
+    lons2 = np.linspace(-180,180,nlons)
+    lats2 = np.linspace(-90,90,nlats)
+    lons2, lats2 = np.meshgrid(lons2,lats2)
+    daynight = np.ones(lons2.shape, np.float)
+    for nlon in range(nlons):
+        daynight[:,nlon] = np.where(lats2[:,nlon]>lats[nlon],0,daynight[:,nlon])
+    return lons2,lats2,daynight
+
+# now, in UTC time.
+d = datetime.utcnow()
+
+# miller projection 
+map = Basemap(projection='mill',lon_0=0)
+# plot coastlines, draw label meridians and parallels.
+map.drawcoastlines()
+map.drawparallels(np.arange(-90,90,30),labels=[1,0,0,0])
+map.drawmeridians(np.arange(-180,180,60),labels=[0,0,0,1])
+# create grid of day=0, night=1
+lons,lats,daynight = daynightgrid(d,1441)
+x,y = map(lons, lats)
+# contour this grid with 1 contour level, specifying colors.
+# (gray for night, axis background for day)
+map.contourf(x,y,daynight,1,colors=[plt.gca().get_axis_bgcolor(),'0.7'])
+plt.title('Day/Night Map for %s (UTC)' %d )
+plt.show()

Deleted: trunk/toolkits/basemap/examples/terminator.py
===================================================================
--- trunk/toolkits/basemap/examples/terminator.py	2009-08-24 18:00:34 UTC (rev 7554)
+++ trunk/toolkits/basemap/examples/terminator.py	2009-08-24 19:03:32 UTC (rev 7555)
@@ -1,75 +0,0 @@
-import numpy as np
-from mpl_toolkits.basemap import Basemap, netcdftime
-import matplotlib.pyplot as plt
-from datetime import datetime
-
-def epem(date):
-    """
-    input: date - datetime object (assumed UTC)
-    ouput: gha - Greenwich hour angle, the angle between the Greenwich
-           meridian and the meridian containing the subsolar point.
-           dec - solar declination.
-    """
-    dg2rad = np.pi/180.
-    rad2dg = 1./dg2rad
-    # compute julian day from UTC datetime object.
-    jday = netcdftime.JulianDayFromDate(date)
-    jd = np.floor(jday) # truncate to integer.
-    # utc hour.
-    ut = d.hour + d.minute/60. + d.second/3600.
-    # calculate number of centuries from J2000
-    t = (jd + (ut/24.) - 2451545.0) / 36525.
-    # mean longitude corrected for aberration
-    l = (280.460 + 36000.770 * t) % 360
-    # mean anomaly
-    g = 357.528 + 35999.050 * t
-    # ecliptic longitude
-    lm = l + 1.915 * np.sin(g*dg2rad) + 0.020 * np.sin(2*g*dg2rad)
-    # obliquity of the ecliptic
-    ep = 23.4393 - 0.01300 * t
-    # equation of time
-    eqtime = -1.915*np.sin(g*dg2rad) - 0.020*np.sin(2*g*dg2rad) \
-            + 2.466*np.sin(2*lm*dg2rad) - 0.053*np.sin(4*lm*dg2rad)
-    # Greenwich hour angle
-    gha = 15*ut - 180 + eqtime
-    # declination of sun
-    dec = np.arcsin(np.sin(ep*dg2rad) * np.sin(lm*dg2rad)) * rad2dg
-    return gha, dec
-
-def daynightgrid(date, nlons):
-    """
-    date is datetime object (assumed UTC).
-    nlons is # of longitudes used to compute terminator."""
-    nlats = ((nlons-1)/2)+1
-    dg2rad = np.pi/180.
-    lons = np.linspace(-180,180,nlons)
-    # compute greenwich hour angle and solar declination
-    # from datetime object (assumed UTC).
-    tau, dec = epem(date) 
-    longitude = lons + tau
-    lats = np.arctan(-np.cos(longitude*dg2rad)/np.tan(dec*dg2rad))/dg2rad
-    lons2 = np.linspace(-180,180,nlons)
-    lats2 = np.linspace(-90,90,nlats)
-    lons2, lats2 = np.meshgrid(lons2,lats2)
-    daynight = np.ones(lons2.shape, np.float)
-    for nlon in range(nlons):
-        daynight[:,nlon] = np.where(lats2[:,nlon]>lats[nlon],0,daynight[:,nlon])
-    return lons2,lats2,daynight
-
-# now, in UTC time.
-d = datetime.utcnow()
-
-# miller projection 
-map = Basemap(projection='mill',lon_0=0)
-# plot coastlines, draw label meridians and parallels.
-map.drawcoastlines()
-map.drawparallels(np.arange(-90,90,30),labels=[1,0,0,0])
-map.drawmeridians(np.arange(-180,180,60),labels=[0,0,0,1])
-# create grid of day=0, night=1
-lons,lats,daynight = daynightgrid(d,1441)
-x,y = map(lons, lats)
-# contour this grid with 1 contour level, specifying colors.
-# (gray for night, axis background for day)
-map.contourf(x,y,daynight,1,colors=[plt.gca().get_axis_bgcolor(),'0.7'])
-plt.title('Day/Night Map for %s (UTC)' %d )
-plt.show()


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