我环顾四周,似乎无法找到解决问题的方法。我的基本问题是,我需要找到所有KML元素的名称,这些元素的子多边形包含具有给定纬度/经度的点。
环顾四周,我发现使用keytree,shapely和lxml可以将所有KML元素过滤到所涉及的多边形,然后访问其父级。但是,当我尝试访问父级的属性时,我总是得到一个空列表。我尝试了以下方法:
def __init__(self):
root=etree.fromstring(open("Example.kml", "r").read())
kmlns = root.tag.split("}")[0][1:]
polygons=root.findall(".//{%s}Polygon"%kmlns)
p = Point(-128.1605,52.474) #this point exists in one of the polygons
hits = filter(
lambda e: shape(keytree.geometry(e)).contains(p),
polygons)
print hits
hit_parent=hits[0].getparent()
print hit_parent.attrib#this prints {}
通过使用pycharm中的调试器,我能够找到多边形所在的行;据此,hits [0]具有sourceline属性,当我在KML文档中转到该行号时,多边形确实包含该点。向上滚动到多边形的父级,我发现它具有属性(即不是空列表)。我是xml和kml解析的新手;我找错地方了吗?这是kml中的面及其父级:
<Placemark>
<name>THIS IS THE NAME</name>
<visibility>0</visibility>
<styleUrl>#falseColor184010</styleUrl>
<ExtendedData>
<SchemaData schemaUrl="#S_AL_TA_BC_2_41_eng_SSSSISSSSSSSSSSSSSSSSSSSSS10">
<SimpleData name="ACQTECH">Computed</SimpleData>
<SimpleData name="METACOVER">Partial</SimpleData>
<SimpleData name="CREDATE">20030416</SimpleData>
<SimpleData name="REVDATE">20130504</SimpleData>
<SimpleData name="ACCURACY">-1</SimpleData>
<SimpleData name="PROVIDER">Federal</SimpleData>
<SimpleData name="DATASETNAM">BC</SimpleData>
<SimpleData name="SPECVERS">1.1</SimpleData>
<SimpleData name="NID">7103157bba3511d892e2080020a0f4c9</SimpleData>
<SimpleData name="ALCODE">07876</SimpleData>
<SimpleData name="LANGUAGE1">English</SimpleData>
<SimpleData name="NAME1">NEEKAS 4</SimpleData>
<SimpleData name="LANGUAGE2">French</SimpleData>
<SimpleData name="NAME2">NEEKAS NO 4</SimpleData>
<SimpleData name="LANGUAGE3">No Language</SimpleData>
<SimpleData name="NAME3">NULL</SimpleData>
<SimpleData name="LANGUAGE4">No Language</SimpleData>
<SimpleData name="NAME4">NULL</SimpleData>
<SimpleData name="LANGUAGE5">No Language</SimpleData>
<SimpleData name="NAME5">NULL</SimpleData>
<SimpleData name="JUR1">BC</SimpleData>
<SimpleData name="JUR2"></SimpleData>
<SimpleData name="JUR3"></SimpleData>
<SimpleData name="JUR4"></SimpleData>
<SimpleData name="ALTYPE">Indian Reserve</SimpleData>
<SimpleData name="WEBREF">http://clss.nrcan.gc.ca/map-carte/mapbrowser-navigateurcartographique-eng.php?cancode=07876</SimpleData>
</SchemaData>
</ExtendedData>
<Polygon>
<outerBoundaryIs>
<LinearRing>
<coordinates>
-128.1615722,52.47385589999999,0 -128.1618475,52.47338730000003,0 -128.1623126999999,52.47275560000004,0 -128.1622705,52.47253640000001,0 -128.162017,52.47243320000002,0 -128.1619326,52.4722527,0 -128.1618904,52.4721108,0 -128.161827,52.47202060000003,0 -128.1615523,52.47204629999998,0 -128.1613199,52.47211069999996,0 -128.1607705,52.47205899999999,0 -128.1604538,52.47172369999999,0 -128.1600750999999,52.47149440000001,0 -128.1600821,52.47510580000001,0 -128.1615621,52.47510469999996,0 -128.1615294999999,52.474926,0 -128.1615508,52.47452629999999,0 -128.1615298,52.47416529999997,0 -128.1615722,52.47385589999999,0
</coordinates>
</LinearRing>
</outerBoundaryIs>
</Polygon>
我想从多边形的父级获得“此名称”。
您的目标文本不是任何元素的属性。给定<Polygon>
为context元素,您想转到parent元素<Placemark>
,然后获取其child元素<name>
。这可以使用XPath在一行中完成:
....
print hits
hit_parent = hits[0].find("./../{%s}name"%kmlns)
print hit_parent.text
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