Python 和 Shapefile：導入 shapefile 后坐標非常大

Question

我下載了波士頓的 shapefile 並想使用下面的代碼將其繪制出來。 但是它給了我一個錯誤ValueError: lat_0 must be between -90.000000 and 90.000000 degrees

結果coords有值(33869.92130000144, 777617.2998000011, 330800.31099999696, 959741.1853)為什么這么大？

波士頓 shapefile 在這里獲得

代碼

# Import Boston shapefile
shapefilename = 'ZIPCODES_NT_POLY'
shp = fiona.open(shapefilename + '.shp')
coords = shp.bounds
shp.close()

w, h = coords[2] - coords[0], coords[3] - coords[1]
extra = 0.01

m = Basemap(
    projection='tmerc', ellps='WGS84',
    lon_0 = np.mean([coords[0], coords[2]]), 
    lat_0 = np.mean([coords[1], coords[3]]), 
    llcrnrlon = coords[0] - extra * w,
    llcrnrlat = coords[1] - extra * h,
    urcrnrlon = coords[2] + extra * w,
    urcrnrlat = coords[3] + extra * h,
    resolution = 'i', suppress_ticks = True)

錯誤

ValueError: lat_0 must be between -90.000000 and 90.000000 degrees

Answer 1

您需要從東距和北距的本地投影重新投影到另一個坐標參考系統。 如果您想要緯度和經度的度數，通常是WGS84或EPSG:4326 。 以下是重新投影它的方法：

import fiona
import pyproj
from functools import partial
from shapely.geometry import box
from shapely.ops import transform

shp = fiona.open('ZIPCODES_NT_POLY.shp', 'r')
p_in = pyproj.Proj(shp.crs)
bound_box = box(*shp.bounds)
shp.close()

p_out = pyproj.Proj({'init': 'EPSG:4326'})  # aka WGS84
project = partial(pyproj.transform, p_in, p_out)

bound_box_wgs84 = transform(project, bound_box)

print('native box: ' + str(bound_box))
print('WGS84 box: ' + str(bound_box_wgs84))

本機框：POLYGON（（330800.310999997 777617.2998000011，330800.310999997 959741.1853，33869.92130000144 959741.1853，33869.92130000144 777617.2998000011，330800.310999997 777617.2998000011））

WGS84盒：POLYGON（（-69.93980848410942 41.23787282321487，-69.899038698261 42.87724537285449，-73.53324195423785 42.8704709990465，-73.48147096070339 41.2312695091688，-69.93980848410942 41.23787282321487））

否則，Basemap 需要的大部分參數都在shp.crs （看看）。

Answer 2

您必須更改坐標參考系。 我推薦geopandas ：

import geopandas as gpd
import matplotlib.pyplot as plt

# load zips with the source projection
shapefilename = 'ZIPCODES_NT_POLY'
zips = gpd.read_file(shapefilename + '.shp')
# convert projection to familiar lat/lon
zips = zips.to_crs('epsg:4326')

zips.plot()
plt.show()