geopandas 的使用以及相关问题

Geoff Boeing

Michelle Fullwood

%matplotlib  inlineimport pandas as pdimport geopandas as gpdfrom geopandas import GeoDataFrame, read_filefrom geopandas.tools import sjoinfrom shapely.geometry import Point, mapping,shapeimport time

from geopandas.geoseries import Polygonfrom geopandas import GeoSeriesp1 = Polygon([(0, 0), (1, 0), (1, 1)])p2 = Polygon([(0, 0), (1, 0), (1, 1), (0, 1)])p3 = Polygon([(2, 0), (3, 0), (3, 1), (2, 1)])g=GeoSeries([p1,p2,p3])g

0         POLYGON ((0 0, 1 0, 1 1, 0 0))1    POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))2    POLYGON ((2 0, 3 0, 3 1, 2 1, 2 0))dtype: object

g.plot()

g.area

0    0.51    1.02    1.0dtype: float64

g.buffer(1).plot()

boros=GeoDataFrame.from_file(r'D:\下载\nybb_16a\nybb_16a\nybb.shp'.decode('utf-8'))

### IPython 带有中文的路径编码为uft-8，需更改编码为acci编码，win下才能识别。

r="D:\下载\nybb_16a\nybb_16a\nybb.shp"import chardetchardet.detect(r)

{‘confidence’: 0.7525, ‘encoding’: ‘utf-8’}

boros.set_index('BoroCode',inplace=True)aa=boros.loc[5]['geometry']boros.loc[5]

BoroName                                          Staten IslandShape_Area                                          1.62382e+09Shape_Leng                                               330470geometry      (POLYGON ((970217.0223999023 145643.3322143555...Name: 5, dtype: object

world=gpd.read_file(gpd.datasets.get_path('naturalearth_lowres'))world.crs

{‘init’: u’epsg:4326’}

cities = gpd.read_file(gpd.datasets.get_path('naturalearth_cities'))

world.head()

continent gdp_md_est geometry iso_a3 name pop_est 0 Asia 22270.0 POLYGON ((61.21081709172574 35.65007233330923,… AFG Afghanistan 28400000.0 1 Africa 110300.0 (POLYGON ((16.32652835456705 -5.87747039146621… AGO Angola 12799293.0 2 Europe 21810.0 POLYGON ((20.59024743010491 41.85540416113361,… ALB Albania 3639453.0 3 Asia 184300.0 POLYGON ((51.57951867046327 24.24549713795111,… ARE United Arab Emirates 4798491.0 4 South America 573900.0 (POLYGON ((-65.50000000000003 -55.199999999999… ARG Argentina 40913584.0

world = gpd.read_file(gpd.datasets.get_path('naturalearth_lowres'))cities = gpd.read_file(gpd.datasets.get_path('naturalearth_cities'))world.head()

continent gdp_md_est geometry iso_a3 name pop_est 0 Asia 22270.0 POLYGON ((61.21081709172574 35.65007233330923,… AFG Afghanistan 28400000.0 1 Africa 110300.0 (POLYGON ((16.32652835456705 -5.87747039146621… AGO Angola 12799293.0 2 Europe 21810.0 POLYGON ((20.59024743010491 41.85540416113361,… ALB Albania 3639453.0 3 Asia 184300.0 POLYGON ((51.57951867046327 24.24549713795111,… ARE United Arab Emirates 4798491.0 4 South America 573900.0 (POLYGON ((-65.50000000000003 -55.199999999999… ARG Argentina 40913584.0

from geopandas import GeoDataFrame  as df# from pandas import DataFrame as dffrom geopandas.geoseries import Pointdf1 = df.set_geometry([Point(0,0), Point(1,1), Point(2,2)])df2 = df.set_geometry('geom1')

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修改默认的notebook的显示的图片大小

import matplotlib.pylab as pylabimport matplotlib.pyplot as pltpylab.rcParams['figure.figsize'] = 20, 20world.plot() 

%matplotlib  inlineworld.plot(color='white',figsize=(20, 20))

控制图像 需要认真的研究bokeh 一个Python 交互式的绘图包

import bokehfrom bokeh import mplfrom bokeh.plotting import output_file, showcitys=cities.to_crs(world.crs)# base=world.plot(color='white')# cities.plot(ax=base,color='red',figsize=(100,100))# show(mpl.to_bokeh())

将交互式的画面显示在notebook 中，bokeh教程,实例

from ipywidgets import interactimport numpy as npfrom bokeh.io import push_notebook, show, output_notebookfrom bokeh.plotting import figureoutput_notebook()x = np.linspace(0, 2*np.pi, 2000)y = np.sin(x)p = figure(title="simple line example", plot_height=300, plot_width=600, y_range=(-5,5))r = p.line(x, y, color="#2222aa", line_width=3)def update(f, w=1, A=1, phi=0):    if   f == "sin": func = np.sin    elif f == "cos": func = np.cos    elif f == "tan": func = np.tan    r.data_source.data['y'] = A * func(w * x + phi)    push_notebook()show(p)