python Shapely使用指南详解
作者：jihite
这篇文章主要介绍了python Shapely使用指南详解,需要的朋友可以参考下
Shapely是一个Python库，用于操作和分析笛卡尔坐标系中的几何对象。
引入包
from shapely.geometry import Point from shapely.geometry import LineString
共有的变量和方法
object.area
Returns the area (float) of the object.
object.bounds
返回对象的（minx,miny,maxx,maxy）元组（float类型）
object.length
返回对象的长度
object.geom_type
返回对象类型
object.distance(other)
返回本对象和另一个对象的距离
object.representative_point()
Returns a cheaply computed point that is guaranteed to be within the geometric object.
>>> from shapely.geometry import Point >>> print Point(0,0).distance(Point(0,1)) 1.0 >>> from shapely.geometry import LineString >>> line = LineString([(0,0), (1,1), (1,2)]) >>> line.area 0.0 >>> line.bounds (0.0, 0.0, 1.0, 2.0) >>> line.length 2.414213562373095 >>> line.geom_type 'LineString'
Point
class Point(coordinates)
三种赋值方式
>>> point = Point(0,0) >>> point_2 = Point((0,0)) >>> point_3 = Point(point)
一个点对象有area和长度都为0
>>> point.area 0.0 >>> point.length 0.0
坐标可以通过coords或x、y、z得到
>>> p = Point(2,3) >>> p.coords <shapely.coords.CoordinateSequence object at 0x7ffbc3d60dd0> >>> list(p.coords) [(2.0, 3.0)] >>> p.x 2.0 >>> p.y 3.0
coords可以被切片
>>> p.coords[:] [(2.0, 3.0)]
LineStrings
LineStrings构造函数传入参数是2个或多个点序列
一个LineStrings对象area为0，长度非0
>>> line = LineString([(0,0), (0,1), (1,2)]) >>> line.area 0.0 >>> line.length 2.414213562373095
获得坐标
>>> line.coords[:] [(0.0, 0.0), (0.0, 1.0), (1.0, 2.0)] >>> list(line.coords) [(0.0, 0.0), (0.0, 1.0), (1.0, 2.0)]
LineString依然可以接受一个同类型对象
>>> line2 = LineString(line) >>> line2.coords[:] [(0.0, 0.0), (0.0, 1.0), (1.0, 2.0)]
常见格式转换
>>> Point(1,1).wkt
'POINT (1 1)'
>>> Point(1,1).wkb
'\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\xf0?\x00\x00\x00\x00\x00\x00\xf0?'
>>> Point(1,1).wkb.encode('hex')
'0101000000000000000000f03f000000000000f03f'
>>>
>>> Point(1,1).wkb.encode('hex')
'0101000000000000000000f03f000000000000f03f'
两者都有loads和dumps方法
对于wkt
>>> from shapely.wkt import dumps, loads >>> s = dumps(Point(1,2)) >>> s 'POINT (1.0000000000000000 2.0000000000000000)' >>> ss = loads(s) >>> ss <shapely.geometry.point.Point object at 0x7ffbc3d783d0> >>> ss.coords[:] [(1.0, 2.0)]
对于wkb
>>> from shapely.wkb import dumps, loads >>> s = dumps(Point(1,2), hex=True) >>> s '0101000000000000000000F03F0000000000000040' >>> ss = loads(s, hex=True) >>> ss <shapely.geometry.point.Point object at 0x7ffbc3d78790> >>> ss.coords <shapely.coords.CoordinateSequence object at 0x7ffbc3d783d0> >>> ss.coords[:] [(1.0, 2.0)]
更多关于python Shapely使用方法请查看下面的相关链接