Re: [Matplotlib-users] basemap scalebar
Hi,
this scalebar is a really good idea!
However, I suggest that all parameters must be optional:
- The position could be by default somewhere in the lower left corner
(for example). It may be interesting to find a best position using
the algo of legend.
- Then length could be estimated from automatically from the map coordinates.
On Tue, Mar 4, 2008 at 3:47 PM, Michael Hearne [EMAIL PROTECTED] wrote:
Jeff - I think the way GMT does it would be okay - they have a latitude of
true scale, which I usually choose as the center latitude of the map.
I was thinking we should allow people to choose the simple or fancy
options. Do you think it will be okay to have the height of the bar and the
text offset be relative to the length of it? I suppose if the height
becomes a problem, people could use the yoffset keyword...
--Mike
On Mar 4, 2008, at 6:05 AM, Jeff Whitaker wrote:
Michael Hearne wrote:
Jeff - That would replicate the simple scale-bar from GMT. Below is my
not-complete attempt at replicating the fancy scale bar. It would need
some options for specifying different units (miles, nautical miles, etc.)
and perhaps some more attention to spacing of the text from the scale bar
and tick marks...
--Mike
Mike: Very nice! Do you want the scale to show the true distance on the
earth (in which case the labels will vary depending on where the label is
placed), or the distance in map projection coordinates (in which case the
labels are constant)? Or perhaps a lat/lon value could be given to specify
where the scale is true?
-Jeff
from numpy import *
from matplotlib.toolkits.basemap import Basemap, pyproj
from pylab import *
# add drawscale method to Basemap class.
class Basemap2(Basemap):
def drawscale(self,lon,lat,length,yoffset=None):
draw a fancy map scale from lon-length/2,lat-yoffset to
lon-length/2,lat-yoffset, label it with actual distance in km
length = length*1000 #input length is km
#we need 5 sets of x coordinates (in map units)
#center of scale
xc,yc = self(lon,lat)
#left edge of scale
lon1,lat1 = self(xc-length/2,yc,inverse=True)
x1,y1 = self(lon1,lat1)
#quarter scale
lon2,lat2 = self(xc-length/4,yc,inverse=True)
x2,y2 = self(lon2,lat2)
#three quarter scale
lon3,lat3 = self(xc+length/4,yc,inverse=True)
x3,y3 = self(lon3,lat3)
#right edge of scale
lon4,lat4 = self(xc+length/2,yc,inverse=True)
x4,y4 = self(lon4,lat4)
if yoffset is None: yoffset = 0.1*length
#plot top line
ytop = yc+yoffset/2
ybottom = yc-yoffset/2
ytick = ybottom - yoffset/2
ytext = ytick - yoffset/2
m.plot([x1,x4],[ytop,ytop],color='k')
#plot bottom line
m.plot([x1,x4],[ybottom,ybottom],color='k')
#plot left edge
m.plot([x1,x1],[ybottom,ytop],color='k')
#plot right edge
m.plot([x4,x4],[ybottom,ytop],color='k')
#make a filled black box from left edge to 1/4 way across
fill([x1,x2,x2,x1,x1],[ytop,ytop,ybottom,ybottom,ytop],'k')
#make a filled white box from 1/4 way across to 1/2 way across
fill([x2,xc,xc,x2,x2],[ytop,ytop,ybottom,ybottom,ytop],'w')
#make a filled white box from 1/2 way across to 3/4 way across
fill([xc,x3,x3,xc,xc],[ytop,ytop,ybottom,ybottom,ytop],'k')
#make a filled white box from 3/4 way across to end
fill([x3,x4,x4,x3,x3],[ytop,ytop,ybottom,ybottom,ytop],'w')
#plot 3 tick marks at left edge, center, and right edge
m.plot([x1,x1],[ytick,ybottom],color='k')
m.plot([xc,xc],[ytick,ybottom],color='k')
m.plot([x4,x4],[ytick,ybottom],color='k')
#label 3 tick marks
text(x1,ytext,'%d' % (0),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
text(xc,ytext,'%d' % (round((length/2)/1000)),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
text(x4,ytext,'%d' % (round((length)/1000)),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
#put units on top
text(xc,ytop+yoffset/2,'km',\
horizontalalignment='center',\
verticalalignment='bottom',\
fontsize=9)
# setup of basemap ('lcc' = lambert conformal conic).
# use major and minor sphere radii from WGS84 ellipsoid.
m =
Basemap2(llcrnrlon=-145.5,llcrnrlat=1.,urcrnrlon=-2.566,urcrnrlat=46.352,\
rsphere=(6378137.00,6356752.3142),\
resolution='l',area_thresh=1000.,projection='lcc',\
lat_1=50.,lon_0=-107.)
# draw coastlines and political boundaries.
m.drawcoastlines()
m.fillcontinents()
# draw parallels and meridians.
# label on left, right and bottom of map.
m.drawparallels(arange(0.,80,20.),labels=[1,1,0,1])
m.drawmeridians(arange(10.,360.,30.),labels=[1,1,0,1])
# draw a line from x1,y to x2,y and label it
Re: [Matplotlib-users] basemap scalebar
Stephane Raynaud wrote:
Hi,
this scalebar is a really good idea!
However, I suggest that all parameters must be optional:
- The position could be by default somewhere in the lower left corner
(for example). It may be interesting to find a best position using
the algo of legend.
- Then length could be estimated from automatically from the map coordinates.
Stephane: While I agree it would be nice to be able to just say 'give
me a scalebar', I don't think having Basemap choose a default location
and size would be very useful. You want the scalebar to be where there
is nothing else drawn on the map, and this will be different in every
case. Plus, you probably want the length to be a nice round number, not
an arbitrary fraction of the map domain.
-Jeff
On Tue, Mar 4, 2008 at 3:47 PM, Michael Hearne [EMAIL PROTECTED] wrote:
Jeff - I think the way GMT does it would be okay - they have a latitude of
true scale, which I usually choose as the center latitude of the map.
I was thinking we should allow people to choose the simple or fancy
options. Do you think it will be okay to have the height of the bar and the
text offset be relative to the length of it? I suppose if the height
becomes a problem, people could use the yoffset keyword...
--Mike
On Mar 4, 2008, at 6:05 AM, Jeff Whitaker wrote:
Michael Hearne wrote:
Jeff - That would replicate the simple scale-bar from GMT. Below is my
not-complete attempt at replicating the fancy scale bar. It would need
some options for specifying different units (miles, nautical miles, etc.)
and perhaps some more attention to spacing of the text from the scale bar
and tick marks...
--Mike
Mike: Very nice! Do you want the scale to show the true distance on the
earth (in which case the labels will vary depending on where the label is
placed), or the distance in map projection coordinates (in which case the
labels are constant)? Or perhaps a lat/lon value could be given to specify
where the scale is true?
-Jeff
from numpy import *
from matplotlib.toolkits.basemap import Basemap, pyproj
from pylab import *
# add drawscale method to Basemap class.
class Basemap2(Basemap):
def drawscale(self,lon,lat,length,yoffset=None):
draw a fancy map scale from lon-length/2,lat-yoffset to
lon-length/2,lat-yoffset, label it with actual distance in km
length = length*1000 #input length is km
#we need 5 sets of x coordinates (in map units)
#center of scale
xc,yc = self(lon,lat)
#left edge of scale
lon1,lat1 = self(xc-length/2,yc,inverse=True)
x1,y1 = self(lon1,lat1)
#quarter scale
lon2,lat2 = self(xc-length/4,yc,inverse=True)
x2,y2 = self(lon2,lat2)
#three quarter scale
lon3,lat3 = self(xc+length/4,yc,inverse=True)
x3,y3 = self(lon3,lat3)
#right edge of scale
lon4,lat4 = self(xc+length/2,yc,inverse=True)
x4,y4 = self(lon4,lat4)
if yoffset is None: yoffset = 0.1*length
#plot top line
ytop = yc+yoffset/2
ybottom = yc-yoffset/2
ytick = ybottom - yoffset/2
ytext = ytick - yoffset/2
m.plot([x1,x4],[ytop,ytop],color='k')
#plot bottom line
m.plot([x1,x4],[ybottom,ybottom],color='k')
#plot left edge
m.plot([x1,x1],[ybottom,ytop],color='k')
#plot right edge
m.plot([x4,x4],[ybottom,ytop],color='k')
#make a filled black box from left edge to 1/4 way across
fill([x1,x2,x2,x1,x1],[ytop,ytop,ybottom,ybottom,ytop],'k')
#make a filled white box from 1/4 way across to 1/2 way across
fill([x2,xc,xc,x2,x2],[ytop,ytop,ybottom,ybottom,ytop],'w')
#make a filled white box from 1/2 way across to 3/4 way across
fill([xc,x3,x3,xc,xc],[ytop,ytop,ybottom,ybottom,ytop],'k')
#make a filled white box from 3/4 way across to end
fill([x3,x4,x4,x3,x3],[ytop,ytop,ybottom,ybottom,ytop],'w')
#plot 3 tick marks at left edge, center, and right edge
m.plot([x1,x1],[ytick,ybottom],color='k')
m.plot([xc,xc],[ytick,ybottom],color='k')
m.plot([x4,x4],[ytick,ybottom],color='k')
#label 3 tick marks
text(x1,ytext,'%d' % (0),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
text(xc,ytext,'%d' % (round((length/2)/1000)),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
text(x4,ytext,'%d' % (round((length)/1000)),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
#put units on top
text(xc,ytop+yoffset/2,'km',\
horizontalalignment='center',\
verticalalignment='bottom',\
fontsize=9)
# setup of basemap ('lcc' = lambert conformal conic).
# use major and minor sphere radii from WGS84 ellipsoid.
m =
Re: [Matplotlib-users] basemap scalebar
On Thu, Mar 6, 2008 at 6:15 PM, Jeff Whitaker [EMAIL PROTECTED] wrote: Stephane Raynaud wrote: Hi, this scalebar is a really good idea! However, I suggest that all parameters must be optional: - The position could be by default somewhere in the lower left corner (for example). It may be interesting to find a best position using the algo of legend. - Then length could be estimated from automatically from the map coordinates. Stephane: While I agree it would be nice to be able to just say 'give me a scalebar', I don't think having Basemap choose a default location and size would be very useful. You want the scalebar to be where there is nothing else drawn on the map, and this will be different in every case. Sure, but the algorithm used by legend tries to put the legend where there is nothing drawn. Plus, you probably want the length to be a nice round number, not an arbitrary fraction of the map domain. I was not thinking about a simple fraction, but a nice length taken within values derived from a Locator scaled by a fraction on the map domain. -Jeff On Tue, Mar 4, 2008 at 3:47 PM, Michael Hearne [EMAIL PROTECTED] wrote: Jeff - I think the way GMT does it would be okay - they have a latitude of true scale, which I usually choose as the center latitude of the map. I was thinking we should allow people to choose the simple or fancy options. Do you think it will be okay to have the height of the bar and the text offset be relative to the length of it? I suppose if the height becomes a problem, people could use the yoffset keyword... --Mike On Mar 4, 2008, at 6:05 AM, Jeff Whitaker wrote: Michael Hearne wrote: Jeff - That would replicate the simple scale-bar from GMT. Below is my not-complete attempt at replicating the fancy scale bar. It would need some options for specifying different units (miles, nautical miles, etc.) and perhaps some more attention to spacing of the text from the scale bar and tick marks... --Mike Mike: Very nice! Do you want the scale to show the true distance on the earth (in which case the labels will vary depending on where the label is placed), or the distance in map projection coordinates (in which case the labels are constant)? Or perhaps a lat/lon value could be given to specify where the scale is true? -Jeff from numpy import * from matplotlib.toolkits.basemap import Basemap, pyproj from pylab import * # add drawscale method to Basemap class. class Basemap2(Basemap): def drawscale(self,lon,lat,length,yoffset=None): draw a fancy map scale from lon-length/2,lat-yoffset to lon-length/2,lat-yoffset, label it with actual distance in km length = length*1000 #input length is km #we need 5 sets of x coordinates (in map units) #center of scale xc,yc = self(lon,lat) #left edge of scale lon1,lat1 = self(xc-length/2,yc,inverse=True) x1,y1 = self(lon1,lat1) #quarter scale lon2,lat2 = self(xc-length/4,yc,inverse=True) x2,y2 = self(lon2,lat2) #three quarter scale lon3,lat3 = self(xc+length/4,yc,inverse=True) x3,y3 = self(lon3,lat3) #right edge of scale lon4,lat4 = self(xc+length/2,yc,inverse=True) x4,y4 = self(lon4,lat4) if yoffset is None: yoffset = 0.1*length #plot top line ytop = yc+yoffset/2 ybottom = yc-yoffset/2 ytick = ybottom - yoffset/2 ytext = ytick - yoffset/2 m.plot([x1,x4],[ytop,ytop],color='k') #plot bottom line m.plot([x1,x4],[ybottom,ybottom],color='k') #plot left edge m.plot([x1,x1],[ybottom,ytop],color='k') #plot right edge m.plot([x4,x4],[ybottom,ytop],color='k') #make a filled black box from left edge to 1/4 way across fill([x1,x2,x2,x1,x1],[ytop,ytop,ybottom,ybottom,ytop],'k') #make a filled white box from 1/4 way across to 1/2 way across fill([x2,xc,xc,x2,x2],[ytop,ytop,ybottom,ybottom,ytop],'w') #make a filled white box from 1/2 way across to 3/4 way across fill([xc,x3,x3,xc,xc],[ytop,ytop,ybottom,ybottom,ytop],'k') #make a filled white box from 3/4 way across to end fill([x3,x4,x4,x3,x3],[ytop,ytop,ybottom,ybottom,ytop],'w') #plot 3 tick marks at left edge, center, and right edge m.plot([x1,x1],[ytick,ybottom],color='k') m.plot([xc,xc],[ytick,ybottom],color='k') m.plot([x4,x4],[ytick,ybottom],color='k') #label 3 tick marks text(x1,ytext,'%d' % (0),\ horizontalalignment='center',\ verticalalignment='top',\ fontsize=9) text(xc,ytext,'%d' % (round((length/2)/1000)),\
Re: [Matplotlib-users] basemap scalebar
Stephane Raynaud wrote: On Thu, Mar 6, 2008 at 6:15 PM, Jeff Whitaker [EMAIL PROTECTED] wrote: Stephane Raynaud wrote: Hi, this scalebar is a really good idea! However, I suggest that all parameters must be optional: - The position could be by default somewhere in the lower left corner (for example). It may be interesting to find a best position using the algo of legend. - Then length could be estimated from automatically from the map coordinates. Stephane: While I agree it would be nice to be able to just say 'give me a scalebar', I don't think having Basemap choose a default location and size would be very useful. You want the scalebar to be where there is nothing else drawn on the map, and this will be different in every case. Sure, but the algorithm used by legend tries to put the legend where there is nothing drawn. Plus, you probably want the length to be a nice round number, not an arbitrary fraction of the map domain. I was not thinking about a simple fraction, but a nice length taken within values derived from a Locator scaled by a fraction on the map domain. Stephane: Sounds reasonable, but I don't have time to work on this now. Patches are always welcome! (including your caching module) -Jeff -- Jeffrey S. Whitaker Phone : (303)497-6313 NOAA/OAR/CDC R/PSD1FAX : (303)497-6449 325 BroadwayBoulder, CO, USA 80305-3328 - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] basemap scalebar
Michael Hearne wrote:
Jeff - That would replicate the simple scale-bar from GMT. Below is
my not-complete attempt at replicating the fancy scale bar. It
would need some options for specifying different units (miles,
nautical miles, etc.) and perhaps some more attention to spacing of
the text from the scale bar and tick marks...
--Mike
Mike: Very nice! Do you want the scale to show the true distance on
the earth (in which case the labels will vary depending on where the
label is placed), or the distance in map projection coordinates (in
which case the labels are constant)? Or perhaps a lat/lon value could
be given to specify where the scale is true?
-Jeff
from numpy import *
from matplotlib.toolkits.basemap import Basemap, pyproj
from pylab import *
# add drawscale method to Basemap class.
class Basemap2(Basemap):
def drawscale(self,lon,lat,length,yoffset=None):
draw a fancy map scale from lon-length/2,lat-yoffset to
lon-length/2,lat-yoffset, label it with actual distance in km
length = length*1000 #input length is km
#we need 5 sets of x coordinates (in map units)
#center of scale
xc,yc = self(lon,lat)
#left edge of scale
lon1,lat1 = self(xc-length/2,yc,inverse=True)
x1,y1 = self(lon1,lat1)
#quarter scale
lon2,lat2 = self(xc-length/4,yc,inverse=True)
x2,y2 = self(lon2,lat2)
#three quarter scale
lon3,lat3 = self(xc+length/4,yc,inverse=True)
x3,y3 = self(lon3,lat3)
#right edge of scale
lon4,lat4 = self(xc+length/2,yc,inverse=True)
x4,y4 = self(lon4,lat4)
if yoffset is None: yoffset = 0.1*length
#plot top line
ytop = yc+yoffset/2
ybottom = yc-yoffset/2
ytick = ybottom - yoffset/2
ytext = ytick - yoffset/2
m.plot([x1,x4],[ytop,ytop],color='k')
#plot bottom line
m.plot([x1,x4],[ybottom,ybottom],color='k')
#plot left edge
m.plot([x1,x1],[ybottom,ytop],color='k')
#plot right edge
m.plot([x4,x4],[ybottom,ytop],color='k')
#make a filled black box from left edge to 1/4 way across
fill([x1,x2,x2,x1,x1],[ytop,ytop,ybottom,ybottom,ytop],'k')
#make a filled white box from 1/4 way across to 1/2 way across
fill([x2,xc,xc,x2,x2],[ytop,ytop,ybottom,ybottom,ytop],'w')
#make a filled white box from 1/2 way across to 3/4 way across
fill([xc,x3,x3,xc,xc],[ytop,ytop,ybottom,ybottom,ytop],'k')
#make a filled white box from 3/4 way across to end
fill([x3,x4,x4,x3,x3],[ytop,ytop,ybottom,ybottom,ytop],'w')
#plot 3 tick marks at left edge, center, and right edge
m.plot([x1,x1],[ytick,ybottom],color='k')
m.plot([xc,xc],[ytick,ybottom],color='k')
m.plot([x4,x4],[ytick,ybottom],color='k')
#label 3 tick marks
text(x1,ytext,'%d' % (0),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
text(xc,ytext,'%d' % (round((length/2)/1000)),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
text(x4,ytext,'%d' % (round((length)/1000)),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
#put units on top
text(xc,ytop+yoffset/2,'km',\
horizontalalignment='center',\
verticalalignment='bottom',\
fontsize=9)
# setup of basemap ('lcc' = lambert conformal conic).
# use major and minor sphere radii from WGS84 ellipsoid.
m =
Basemap2(llcrnrlon=-145.5,llcrnrlat=1.,urcrnrlon=-2.566,urcrnrlat=46.352,\
rsphere=(6378137.00,6356752.3142),\
resolution='l',area_thresh=1000.,projection='lcc',\
lat_1=50.,lon_0=-107.)
# draw coastlines and political boundaries.
m.drawcoastlines()
m.fillcontinents()
# draw parallels and meridians.
# label on left, right and bottom of map.
m.drawparallels(arange(0.,80,20.),labels=[1,1,0,1])
m.drawmeridians(arange(10.,360.,30.),labels=[1,1,0,1])
# draw a line from x1,y to x2,y and label it with distance in km.
length = 3000 #kilometers
x1,y1 = 0.25*m.xmax, 0.25*m.ymax
lon1,lat1 = m(x1,y1,inverse=True)
m.drawscale(lon1,lat1,length)
title('a fancy map scale')
show()
--
Michael Hearne
[EMAIL PROTECTED] mailto:[EMAIL PROTECTED]
(303) 273-8620
USGS National Earthquake Information Center
1711 Illinois St. Golden CO 80401
Senior Software Engineer
Synergetics, Inc.
--
--
Jeffrey S. Whitaker Phone : (303)497-6313
NOAA/OAR/CDC R/PSD1FAX : (303)497-6449
325 BroadwayBoulder, CO, USA 80305-3328
-
This SF.net email is sponsored by: Microsoft
Defy all challenges. Microsoft(R) Visual Studio 2008.
Re: [Matplotlib-users] basemap scalebar
Jeff - I think the way GMT does it would be okay - they have a
latitude of true scale, which I usually choose as the center latitude
of the map.
I was thinking we should allow people to choose the simple or
fancy options. Do you think it will be okay to have the height of
the bar and the text offset be relative to the length of it? I
suppose if the height becomes a problem, people could use the yoffset
keyword...
--Mike
On Mar 4, 2008, at 6:05 AM, Jeff Whitaker wrote:
Michael Hearne wrote:
Jeff - That would replicate the simple scale-bar from GMT.
Below is my not-complete attempt at replicating the fancy scale
bar. It would need some options for specifying different units
(miles, nautical miles, etc.) and perhaps some more attention to
spacing of the text from the scale bar and tick marks...
--Mike
Mike: Very nice! Do you want the scale to show the true distance
on the earth (in which case the labels will vary depending on where
the label is placed), or the distance in map projection coordinates
(in which case the labels are constant)? Or perhaps a lat/lon
value could be given to specify where the scale is true?
-Jeff
from numpy import *
from matplotlib.toolkits.basemap import Basemap, pyproj
from pylab import *
# add drawscale method to Basemap class.
class Basemap2(Basemap):
def drawscale(self,lon,lat,length,yoffset=None):
draw a fancy map scale from lon-length/2,lat-yoffset to
lon-length/2,lat-yoffset, label it with actual distance in
km
length = length*1000 #input length is km
#we need 5 sets of x coordinates (in map units)
#center of scale
xc,yc = self(lon,lat)
#left edge of scale
lon1,lat1 = self(xc-length/2,yc,inverse=True)
x1,y1 = self(lon1,lat1)
#quarter scale
lon2,lat2 = self(xc-length/4,yc,inverse=True)
x2,y2 = self(lon2,lat2)
#three quarter scale
lon3,lat3 = self(xc+length/4,yc,inverse=True)
x3,y3 = self(lon3,lat3)
#right edge of scale
lon4,lat4 = self(xc+length/2,yc,inverse=True)
x4,y4 = self(lon4,lat4)
if yoffset is None: yoffset = 0.1*length
#plot top line
ytop = yc+yoffset/2
ybottom = yc-yoffset/2
ytick = ybottom - yoffset/2
ytext = ytick - yoffset/2
m.plot([x1,x4],[ytop,ytop],color='k')
#plot bottom line
m.plot([x1,x4],[ybottom,ybottom],color='k')
#plot left edge
m.plot([x1,x1],[ybottom,ytop],color='k')
#plot right edge
m.plot([x4,x4],[ybottom,ytop],color='k')
#make a filled black box from left edge to 1/4 way across
fill([x1,x2,x2,x1,x1],[ytop,ytop,ybottom,ybottom,ytop],'k')
#make a filled white box from 1/4 way across to 1/2 way across
fill([x2,xc,xc,x2,x2],[ytop,ytop,ybottom,ybottom,ytop],'w')
#make a filled white box from 1/2 way across to 3/4 way across
fill([xc,x3,x3,xc,xc],[ytop,ytop,ybottom,ybottom,ytop],'k')
#make a filled white box from 3/4 way across to end
fill([x3,x4,x4,x3,x3],[ytop,ytop,ybottom,ybottom,ytop],'w')
#plot 3 tick marks at left edge, center, and right edge
m.plot([x1,x1],[ytick,ybottom],color='k')
m.plot([xc,xc],[ytick,ybottom],color='k')
m.plot([x4,x4],[ytick,ybottom],color='k')
#label 3 tick marks
text(x1,ytext,'%d' % (0),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
text(xc,ytext,'%d' % (round((length/2)/1000)),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
text(x4,ytext,'%d' % (round((length)/1000)),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
#put units on top
text(xc,ytop+yoffset/2,'km',\
horizontalalignment='center',\
verticalalignment='bottom',\
fontsize=9)
# setup of basemap ('lcc' = lambert conformal conic).
# use major and minor sphere radii from WGS84 ellipsoid.
m = Basemap2
(llcrnrlon=-145.5,llcrnrlat=1.,urcrnrlon=-2.566,urcrnrlat=46.352,\
rsphere=(6378137.00,6356752.3142),\
resolution='l',area_thresh=1000.,projection='lcc',\
lat_1=50.,lon_0=-107.)
# draw coastlines and political boundaries.
m.drawcoastlines()
m.fillcontinents()
# draw parallels and meridians.
# label on left, right and bottom of map.
m.drawparallels(arange(0.,80,20.),labels=[1,1,0,1])
m.drawmeridians(arange(10.,360.,30.),labels=[1,1,0,1])
# draw a line from x1,y to x2,y and label it with distance in km.
length = 3000 #kilometers
x1,y1 = 0.25*m.xmax, 0.25*m.ymax
lon1,lat1 = m(x1,y1,inverse=True)
m.drawscale(lon1,lat1,length)
title('a fancy map scale')
show()
--
Michael Hearne
[EMAIL PROTECTED] mailto:[EMAIL PROTECTED]
(303) 273-8620
USGS National Earthquake Information Center
1711 Illinois St. Golden CO 80401
Senior Software Engineer
Synergetics, Inc.
Re: [Matplotlib-users] basemap scalebar
Jeff - That would replicate the simple scale-bar from GMT. Below
is my not-complete attempt at replicating the fancy scale bar. It
would need some options for specifying different units (miles,
nautical miles, etc.) and perhaps some more attention to spacing of
the text from the scale bar and tick marks...
--Mike
from numpy import *
from matplotlib.toolkits.basemap import Basemap, pyproj
from pylab import *
# add drawscale method to Basemap class.
class Basemap2(Basemap):
def drawscale(self,lon,lat,length,yoffset=None):
draw a fancy map scale from lon-length/2,lat-yoffset to
lon-length/2,lat-yoffset, label it with actual distance in km
length = length*1000 #input length is km
#we need 5 sets of x coordinates (in map units)
#center of scale
xc,yc = self(lon,lat)
#left edge of scale
lon1,lat1 = self(xc-length/2,yc,inverse=True)
x1,y1 = self(lon1,lat1)
#quarter scale
lon2,lat2 = self(xc-length/4,yc,inverse=True)
x2,y2 = self(lon2,lat2)
#three quarter scale
lon3,lat3 = self(xc+length/4,yc,inverse=True)
x3,y3 = self(lon3,lat3)
#right edge of scale
lon4,lat4 = self(xc+length/2,yc,inverse=True)
x4,y4 = self(lon4,lat4)
if yoffset is None: yoffset = 0.1*length
#plot top line
ytop = yc+yoffset/2
ybottom = yc-yoffset/2
ytick = ybottom - yoffset/2
ytext = ytick - yoffset/2
m.plot([x1,x4],[ytop,ytop],color='k')
#plot bottom line
m.plot([x1,x4],[ybottom,ybottom],color='k')
#plot left edge
m.plot([x1,x1],[ybottom,ytop],color='k')
#plot right edge
m.plot([x4,x4],[ybottom,ytop],color='k')
#make a filled black box from left edge to 1/4 way across
fill([x1,x2,x2,x1,x1],[ytop,ytop,ybottom,ybottom,ytop],'k')
#make a filled white box from 1/4 way across to 1/2 way across
fill([x2,xc,xc,x2,x2],[ytop,ytop,ybottom,ybottom,ytop],'w')
#make a filled white box from 1/2 way across to 3/4 way across
fill([xc,x3,x3,xc,xc],[ytop,ytop,ybottom,ybottom,ytop],'k')
#make a filled white box from 3/4 way across to end
fill([x3,x4,x4,x3,x3],[ytop,ytop,ybottom,ybottom,ytop],'w')
#plot 3 tick marks at left edge, center, and right edge
m.plot([x1,x1],[ytick,ybottom],color='k')
m.plot([xc,xc],[ytick,ybottom],color='k')
m.plot([x4,x4],[ytick,ybottom],color='k')
#label 3 tick marks
text(x1,ytext,'%d' % (0),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
text(xc,ytext,'%d' % (round((length/2)/1000)),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
text(x4,ytext,'%d' % (round((length)/1000)),\
horizontalalignment='center',\
verticalalignment='top',\
fontsize=9)
#put units on top
text(xc,ytop+yoffset/2,'km',\
horizontalalignment='center',\
verticalalignment='bottom',\
fontsize=9)
# setup of basemap ('lcc' = lambert conformal conic).
# use major and minor sphere radii from WGS84 ellipsoid.
m = Basemap2
(llcrnrlon=-145.5,llcrnrlat=1.,urcrnrlon=-2.566,urcrnrlat=46.352,\
rsphere=(6378137.00,6356752.3142),\
resolution='l',area_thresh=1000.,projection='lcc',\
lat_1=50.,lon_0=-107.)
# draw coastlines and political boundaries.
m.drawcoastlines()
m.fillcontinents()
# draw parallels and meridians.
# label on left, right and bottom of map.
m.drawparallels(arange(0.,80,20.),labels=[1,1,0,1])
m.drawmeridians(arange(10.,360.,30.),labels=[1,1,0,1])
# draw a line from x1,y to x2,y and label it with distance in km.
length = 3000 #kilometers
x1,y1 = 0.25*m.xmax, 0.25*m.ymax
lon1,lat1 = m(x1,y1,inverse=True)
m.drawscale(lon1,lat1,length)
title('a fancy map scale')
show()
--
Michael Hearne
[EMAIL PROTECTED]
(303) 273-8620
USGS National Earthquake Information Center
1711 Illinois St. Golden CO 80401
Senior Software Engineer
Synergetics, Inc.
--
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