沿着多线插入每个X距离的形状

Question

如果我有一个形状多线的对象，其中包含许多行，每个行的总长度为50km（从原点开始追踪），我想每隔X米沿多行插值（让我们说100米），返回每隔100米塑造一点点物体，我该怎样才能实现这个目标？

这是我到目前为止所做的，但它只返回一个不同的点（当我知道它应该返回数千，在ArcMap中测试）：

points = []

for x in range(100,50000,100):
    x,y = multiline.interpolate(x).xy
    xy = (x[0],y[0])
    points.append(xy)

trim = list(set(points))

以下是修剪包含的内容：

[(-90.5864707030599, 38.4688716729703)]

如果我将多线分成单独的线，我可以获得更多的分数（162），但仍然不是我应该产生的1000s：

lines_shape = []

# breaking out individual lines into shapely line strings
for line in multiline:
    lines_shapes.append(gm.asLineString(line))

points = []

# interpolating points along each line
for line in lines_shapes:
    for x in range(100,50000,100):
        points.append(line.interpolate(x))

point_list = []
for point in points:
    x,y = point.xy
    xy = (x[0],y[0])
    point_list.append(xy)

trim = list(set(point_list))

和trim包含：

[(-90.4766827033434, 38.5972414054466), (-90.5461231698478, 38.5000688058116), (-90.4968889030998, 38.5464768729898), (-90.6189469029766, 38.4718782063951), (-90.513144169767, 38.5129150061034), (-90.5810937033111, 38.5323612724354), (-90.5396967035394, 38.5864442726652), (-90.6868857696619, 38.447798672452), (-90.6213193028429, 38.5146844725911), (-90.509758103553, 38.5536796727591), (-90.476078103521, 38.546296205486), (-90.6427893693333, 38.5555682724382), (-90.6217561026614, 38.5147302723649), (-90.630436369842, 38.5000560723107), (-90.4760629697296, 38.5914768059899), (-90.6849423697939, 38.4566312056467), (-90.6538383698443, 38.4599348058277), (-90.4699029698455, 38.5837950057152), (-90.6694679700701, 38.4474470726055), (-90.6829395031549, 38.4198408724397), (-90.6732927030951, 38.4360894058827), (-90.5866617028747, 38.5332390062557), (-90.6961129028875, 38.4531938061303), (-90.5947731029956, 38.4539120730648), (-90.5142317702794, 38.5249724721824), (-90.5903123694197, 38.5034458725098), (-90.5755567699284, 38.5000690063604), (-90.56752770364, 38.5589170059954), (-90.6271141698824, 38.5430544723665), (-90.6201437702182, 38.4550620064875), (-90.6180047030539, 38.5000570723568), (-90.6589975699812, 38.500065872223), (-90.685946302779, 38.4505508056563), (-90.6840849030951, 38.4547842059075), (-90.6854941029699, 38.4134104059469), (-90.5918703027716, 38.5000662058715), (-90.5471115031927, 38.4808140060424), (-90.463451370184, 38.5525954725834), (-90.6780159694608, 38.4460308724081), (-90.5896267029094, 38.5346980060887), (-90.5807949701111, 38.5325790054973), (-90.7004947695174, 38.4727768728354), (-90.5955769035506, 38.5373834725497), (-90.6569789697031, 38.4542776061077), (-90.6253669031594, 38.521868606032), (-90.6565429028321, 38.4538942062337), (-90.4636589696851, 38.552869806277), (-90.634338969767, 38.546211672811), (-90.4360581033981, 38.5162080059754), (-90.478937169714, 38.604583072231), (-90.6238845029668, 38.5403794056656), (-90.5115069701699, 38.5170084061937), (-90.6607629031848, 38.4788458064697), (-90.6182993029698, 38.4996076730365), (-90.6795531698423, 38.4464060057138), (-90.5715115033526, 38.5319224725247), (-90.6601255698386, 38.4660196727507), (-90.5944027028219, 38.4399328061353), (-90.6658113032484, 38.5630904727274), (-90.657297702926, 38.4486316730944), (-90.6076871697265, 38.5411054058703), (-90.5189131030566, 38.4958198724699), (-90.4633435036991, 38.5571938060298), (-90.4550633700778, 38.5794588057595), (-90.6551231026484, 38.5026692062996), (-90.6304847695558, 38.4814012057819), (-90.6293281694588, 38.5510622058365), (-90.5337045036593, 38.5480590727484), (-90.5636725699325, 38.5031146728847), (-90.5893179035978, 38.5349642063136), (-90.5502847700255, 38.5531414725813), (-90.6577657029242, 38.4673132728702), (-90.6842995029191, 38.45499127301), (-90.596995102941, 38.536759005804), (-90.4590855033927, 38.579707805551), (-90.618116169525, 38.5138608060121), (-90.662823570151, 38.4436198061903), (-90.5324573031614, 38.5290608063917), (-90.4761187699646, 38.5460198060497), (-90.4365065035716, 38.5163978060946), (-90.5993421032549, 38.4517628723399), (-90.6580597695421, 38.4672556730918), (-90.4697125698785, 38.5713498724789), (-90.6246789694582, 38.5225716726252), (-90.5623807028065, 38.539724406037), (-90.5255411029389, 38.5592538722488), (-90.6779729027267, 38.4309624725214), (-90.5757351702413, 38.5712982055281), (-90.4349003036055, 38.5470764060318), (-90.4881969699136, 38.5968882057062), (-90.5654833701608, 38.5641550721791), (-90.6243467697869, 38.5407896062358), (-90.6833993696845, 38.4554192064123), (-90.5125843031225, 38.5353802722622), (-90.4343933036075, 38.5320694055591), (-90.5949243033133, 38.4437996058484), (-90.6531879693487, 38.5465062727268), (-90.4678253704438, 38.5769334060321), (-90.6560765692776, 38.4512860059256), (-90.6705015033411, 38.4387672065226), (-90.4510205703424, 38.5293378056758), (-90.5965189694742, 38.453478006286), (-90.5158851037139, 38.5293438059525), (-90.5153219032826, 38.5000608728918), (-90.571685370183, 38.5322450728324), (-90.5907731028958, 38.5035282063425), (-90.562387970228, 38.5396736725824), (-90.5632127699527, 38.5000698058576), (-90.4351277034801, 38.5467304062636), (-90.6846297033974, 38.4247822729648), (-90.4300920979354, 38.5121736658553), (-90.6077071031996, 38.5414430059705), (-90.700472969951, 38.4725166728872), (-90.6083531698623, 38.5440140058222), (-90.6611483697009, 38.478763472637), (-90.5148001696915, 38.5340326723505), (-90.6261891029441, 38.4987850056043), (-90.6077131034763, 38.5415200724739), (-90.5714903701838, 38.5588274721905), (-90.487086969987, 38.5953794059149), (-90.6309363029674, 38.4813284731115), (-90.4375485030603, 38.5798804061361), (-90.4348689037762, 38.5318386727971), (-90.4636395029601, 38.5528440056267), (-90.5537693695601, 38.5918534726398), (-90.686189369743, 38.45065887269), (-90.5137219032426, 38.5459956061927), (-90.4708333032137, 38.5588582056221), (-90.562663570167, 38.5400910056759), (-90.5898827695735, 38.4573650056716), (-90.6541333699584, 38.4598728056666), (-90.5201981695093, 38.5275174726339), (-90.5279559031418, 38.5197458058049), (-90.4969485029704, 38.5468012728409), (-90.6963449693442, 38.4523242057786), (-90.5869187695849, 38.5329812056987), (-90.7090465028932, 38.4391836726696), (-90.4722723695735, 38.5676876055788), (-90.6076811029, 38.541104472374), (-90.6281757035453, 38.4421816724275), (-90.5341799698291, 38.5482110060135), (-90.5948001033415, 38.494925272764), (-90.5864707030599, 38.4688716729703), (-90.5419337032772, 38.5685326058754), (-90.7019565698392, 38.4481112057488), (-90.6253121695204, 38.521868606032), (-90.5138205031131, 38.5456764727715), (-90.5529913031055, 38.455285806376), (-90.5293321032933, 38.5986526054135), (-90.6309013697018, 38.5463032723585), (-90.4975365696563, 38.6037882720911), (-90.6184813032689, 38.4720362730366), (-90.6781275699308, 38.4462692727899), (-90.5651579702635, 38.4796824727488), (-90.6532305027848, 38.5024180058671), (-90.6545907030978, 38.5581974062657), (-90.5950401027179, 38.4950944055632), (-90.6468105700511, 38.5573522728695), (-90.6698367029009, 38.4476676727061), (-90.4501431701705, 38.5848148728883), (-90.577996903134, 38.503304272455), (-90.6713375697724, 38.545723072942)]

也许问题出在我传递插值的论证中？我如何知道预期/假设距离在哪个单位？

修改

多线的定义 - 此代码在json文件中打开一个geojson特征集合对象，然后拉出特定的geojson多线串并将其转换为一个形状多线串的对象。

from shapely import geometry as gm
import json

file = 'Geometries_GEOJSON.json'

with open(file) as input_file:
    data = json.load(input_file)

geojson_multilines = data['features'][1]['geometry']

multiline = gm.shape(geojson_multilines)

这是它的样子：

转换前，作为geojson对象：

{u'type': u'MultiLineString', u'coordinates': [[[-90.4360581033981, 38.5162080059754], [-90.4356193034874, 38.5151156723311], [-90.4349665036006, 38.5145500059587], [-90.4312643032044, 38.5129080723304], [-90.4300920979354, 38.5121736658553]], [[-90.4348689037762, 38.5318386727971], [-90.4353155700569, 38.5236814729023], [-90.4360581033981, 38.5162080059754]].......

转换后，作为geojson对象：

MULTILINESTRING ((-90.4360581033981 38.5162080059754, -90.4356193034874 38.5151156723311, -90.43496650360061 38.5145500059587, -90.4312643032044 38.5129080723304, -90.4300920979354 38.5121736658553), (-90.43486890377621 38.5318386727971, -90.4353155700569 38.5236814729023, -90.4360581033981 38.5162080059754),........

在ArcMap中映射的一个此类对象的示例：

Answer 1

正如@mgc指出的那样，您必须将数据投影到具有以米为单位的距离单位的笛卡尔坐标参考系统。

我使用函数重新分配顶点，它使用interpolate线性参考方法。距离参数仅是近似的，因为线串的总距离可能不是优选距离的倍数。此函数仅适用于[Multi] LineString几何类型。

from shapely import wkt
from shapely.geometry import LineString

def redistribute_vertices(geom, distance):
    if geom.geom_type == 'LineString':
        num_vert = int(round(geom.length / distance))
        if num_vert == 0:
            num_vert = 1
        return LineString(
            [geom.interpolate(float(n) / num_vert, normalized=True)
             for n in range(num_vert + 1)])
    elif geom.geom_type == 'MultiLineString':
        parts = [redistribute_vertices(part, distance)
                 for part in geom]
        return type(geom)([p for p in parts if not p.is_empty])
    else:
        raise ValueError('unhandled geometry %s', (geom.geom_type,))

# E.g., every 100 m on a projected MultiLineString
multiline_r = redistribute_vertices(multiline, 100)

Answer 2

在您的第一段代码中，您正在迭代150米乘150米，但您的数据集似乎在经度 - 纬度。您应该以米为单位重新投影（在适用于您所在区域的CRS中），并以objet为单位获取distance参数。 例子来自shapely documentation：

from functools import partial
import pyproj

project = partial(
    pyproj.transform,
    pyproj.Proj(init=’espg:4326’),
    pyproj.Proj(init=’epsg:26913’)) # Replace by the appropriate CRS
g2 = transform(project, g1) # g1 is a shapely geometry

您还可以使用interpolate函数中的标准化值来避免转换：

# Progress of 10% of the length:
line.interpolate(0.10, normalized=True)