Question

data = "GEOMETRYCOLLECTION (POINT (-8.9648437500000000 -4.1308593750000000), POINT (2.0214843750000000 -2.6367187500000000), POINT (-1.4062500000000000 -11.1621093750000000), POINT (-11.9531250000000000,-10.8984375000000000), POLYGON ((-21.6210937500000000 1.8457031250000000,2.4609375000000000 2.1972656250000000, -18.9843750000000000 -3.6914062500000000, -22.6757812500000000 -3.3398437500000000, -22.1484375000000000 -2.6367187500000000, -21.6210937500000000 1.8457031250000000)),LINESTRING (-11.9531250000000000 11.3378906250000000, 7.7343750000000000 11.5136718750000000, 12.3046875000000000 2.5488281250000000, 12.2167968750000000 1.6699218750000000, 14.5019531250000000 3.9550781250000000))"

出于这个原因，我想创建3个单独的词组。点。多边形。 LineString。对于每个Point = {co-ord1，cord2，cord3 ...} 类似于Polygon和LineString。什么是最好的方法呢？

我想创建3个独立的变量。一个是拥有所有坐标的Point。与Polygon和LineString相同。

Answer 1

好的，如果你可以确保用,分隔所有数字，那么我可以用一些简单的python类和eval函数来做你想做的事情。基本上，为每个POINT，POLYGON等定义一个类。这样，您可以将字符串转换为一个表达式，该表达式使得一个GEOMETRYCOLLECTION对象脱离POINT，POLYGON，LINESTRING对象。请记住，在字符串中最好将coords定义为size-2元组，((A,B), (C,D))而不是(A B, C, D)。如果你能做到，那么剩下的就是

class Coords(object) :
    """
    Simple base class, stores ctor arguments as a tuple.
    """
    def __init__(self, *args) :
        self.coords = tuple(args)

class POINT(Coords) :
    """
    Dummy class, to have handle on class name.
    """
    pass

# similar definitions for POLYGON and LINESTRING

class GEOMETRYCOLLECTION(object) :
    def __init__(self, *args) :
        self.data = {} #store data in a type name -> coord tuple map
        for arg in args:
            if type(arg).__name__ not in self.data.keys() :
                self.data[type(arg).__name__] = [arg.coords]
            else :
                self.data[type(arg).__name__].append(arg.coords)
    def __getitem__(self,key) :
        # allow access via [] operator
        return self.data.get(key)

然后在你的代码中（一旦你将字符串修改为我建议的格式）

data = "GEOMETRYCOLLECTION (POINT (-8.9648437500000000,  ......"
geom = eval(data)
point_coords = geom['POINT']

等等。这有点像黑客，我相信有更优雅的方法来实现这一点。

这一行会产生两个POINT坐标和一个POLYGON：

data="GEOMETRYCOLLECTION (POINT (-8.9648437500000000, -4.1308593750000000), POINT (2.0214843750000000, -2.6367187500000000), POLYGON ((-21.6210937500000000, 1.8457031250000000),(2.4609375000000000, 2.1972656250000000), (-18.9843750000000000, -3.6914062500000000), (-22.6757812500000000, -3.3398437500000000)))"

如何在python中遍历一个字典并从中创建两个独立的字典？

1 个答案: