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+--- Thread: Issue plotting coordinates using Basemap (/thread-2345.html)
Issue plotting coordinates using Basemap - kiton - Mar-08-2017
Having extracted geo coordinates from Twitter JSON, I created a new pandas data frame:
df3 Out[140]: lat lon pos 63 -26.298376 28.070223 (-26.29837597, 28.07022309) 116 1.487180 124.861180 (1.48718, 124.86118) 199 33.708842 -84.294066 (33.70884247, -84.29406577) 349 35.368816 -96.955488 (35.36881649, -96.95548791) 379 14.830463 120.284751 (14.83046326, 120.2847507) 859 35.151530 -80.727347 (35.15153029, -80.72734744)Now, my goal is to plot the coordinates on the map using Basemap:
import matplotlib.pyplot as plt
from mpl_toolkits.basemap import Basemap
# Set map size
fig, ax = plt.subplots(figsize=(10,20))
# Set USA coordinates
m = Basemap(resolution='c', # c, l, i, h, f or None
projection='merc',
lat_0=39, lon_0=-99, ## center of the map
llcrnrlon=-125, llcrnrlat= 25, urcrnrlon=-65, urcrnrlat=49)
# Read county boundaries
shp_info = m.readshapefile('cb_2015_us_county_500k',
'counties',
drawbounds=True)
# Set geo coordinates to be plotted
lats = df3['lat'] [:] #all values from column lat
lons = df3['lon'] [:] #all values from column lon
x,y = m(lats, lons)
# Place points on the map
m.plot(x, y, 'ro', markersize=5)
m.bluemarble()
plt.show()However, for some reason I get this error:Error: TypeError Traceback (most recent call last)
TypeError: expected a writable bytes-like object
The above exception was the direct cause of the following exception:
SystemError Traceback (most recent call last)
<ipython-input-144-d258e6080d9d> in <module>()
18 lats = df3['lat'] [:]
19 lons = df3['lon'] [:]
---> 20 x,y = m(lats, lons)
21
22 # place it on the map
/Users/mymac/anaconda/lib/python3.6/site-packages/mpl_toolkits/basemap/__init__.py in __call__(self, x, y, inverse)
1146 except TypeError:
1147 y = [_dg2rad*yy for yy in y]
-> 1148 xout,yout = self.projtran(x,y,inverse=inverse)
1149 if self.celestial and inverse:
1150 try:
/Users/mymac/anaconda/lib/python3.6/site-packages/mpl_toolkits/basemap/proj.py in __call__(self, *args, **kw)
284 outxy = self._proj4(xy, inverse=inverse)
285 else:
--> 286 outx,outy = self._proj4(x, y, inverse=inverse)
287 if inverse:
288 if self.projection in ['merc','mill','gall']:
/Users/mymac/anaconda/lib/python3.6/site- packages/mpl_toolkits/basemap/pyproj.py in __call__(self, *args, **kw)
386 _proj.Proj._inv(self, inx, iny, radians=radians, errcheck=errcheck)
387 else:
--> 388 _proj.Proj._fwd(self, inx, iny, radians=radians, errcheck=errcheck)
389 # if inputs were lists, tuples or floats, convert back.
390 outx = _convertback(xisfloat,xislist,xistuple,inx)
_proj.pyx in _proj.Proj._fwd (src/_proj.c:1571)()
SystemError: <class 'RuntimeError'> returned a result with an error setRE: Issue plotting coordinates using Basemap - zivoni - Mar-08-2017
I have no experience with mpl_toolkits, but considering that it is package associated with matplotlib, I wonder what happens if you try
x, y = m(lats.values, lons.values) # instead of x,y=m(lats, lons)
RE: Issue plotting coordinates using Basemap - kiton - Mar-08-2017
It did work! Good catch, sir :)
The result (see attached), however, presents a map with county grid but without coordinates plotted. And the following error. Weird, isn't it?
Error:[color=#000000]/Users/mymac/anaconda/lib/python3.6/site-packages/mpl_toolkits/basemap/__init__.py:3260: MatplotlibDeprecationWarning: The ishold function was deprecated in version 2.0.
b = ax.ishold()
/Users/mymac/anaconda/lib/python3.6/site-packages/mpl_toolkits/basemap/__init__.py:3269: MatplotlibDeprecationWarning: axes.hold is deprecated.
See the API Changes document (http://matplotlib.org/api/api_changes.html)
for more details.
ax.hold(b)
/Users/mymac/anaconda/lib/python3.6/site-packages/mpl_toolkits/basemap/__init__.py:3296: MatplotlibDeprecationWarning: The ishold function was deprecated in version 2.0.
b = ax.ishold()
/Users/mymac/anaconda/lib/python3.6/site-packages/mpl_toolkits/basemap/__init__.py:3305: MatplotlibDeprecationWarning: axes.hold is deprecated.
See the API Changes document (http://matplotlib.org/api/api_changes.html)
for more details.
ax.hold(b)[/color]RE: Issue plotting coordinates using Basemap - zivoni - Mar-09-2017
It is not an error, just a warning about using deprecated function. It seems that some internal function in basemap uses it and according to matplotlib issues it is already patched, so it will disappear after next update. For now you can ignore it.
I downloaded mpl_toolkits and tried it with your code and fictional data. This code:
# Place points on the map x, y = m(np.array([-104, -100, -90]), np.array([40, 42, 38])) m.plot(x, y, 'ro', markersize=15)seems to be working to plot locations, so maybe you need to check your coordinate's values?
[Image: bgBHUtJ.png]
RE: Issue plotting coordinates using Basemap - kiton - Mar-09-2017
I switched the coordinates like:
x, y = m(lons.values, lats.values) # instead of x, y = m(lats.values, lons.values)...and its all there :) Thanks a lot for help again! I'll double-check how the values were recorded in the data frame.
RE: Issue plotting coordinates using Basemap - Larz60+ - Mar-09-2017
Just a suggestion (if you can do this) make the line thickness a bit thinner and white (or at least lighter color) for his view.
In order to work right, that may have to be adjusted when zooming in.