使用pykml解析kml时出现Lxml错误

Question

我试图使用pykml解析包含多个placemark的kml文件。我想在kml的描述中编辑HTML代码，主要用于Google中地理数据的可视化。我研究了很多方法来做到这一点：

• Extract Coordinates from KML BatchGeo File with Python
• Read kml file with multiple placemarks in pykml
• Using pyKML to parse KML Document
• KML to string in Python?

但是，我总是得到如下所示的lxml错误。:(

    Traceback (most recent call last):
    File "C:\Users\Arellano\Copy\BSGE\2015-2016 SUMMER\trial7.py", line 5, in <module>
    root = parser.fromstring(open('trim_KML.kml', 'r').read())
  File "C:\Program Files (x86)\Python2.7.10\lib\site-packages\pykml-0.1.0-py2.7.egg\pykml\parser.py", line 41, in fromstring
    return objectify.fromstring(text)
  File "src/lxml/lxml.objectify.pyx", line 1801, in lxml.objectify.fromstring (src\lxml\lxml.objectify.c:25171)
  File "src/lxml/lxml.etree.pyx", line 3213, in lxml.etree.fromstring (src\lxml\lxml.etree.c:77697)
  File "src/lxml/parser.pxi", line 1819, in lxml.etree._parseMemoryDocument (src\lxml\lxml.etree.c:116494)
  File "src/lxml/parser.pxi", line 1707, in lxml.etree._parseDoc (src\lxml\lxml.etree.c:115144)
  File "src/lxml/parser.pxi", line 1079, in lxml.etree._BaseParser._parseDoc (src\lxml\lxml.etree.c:109543)
  File "src/lxml/parser.pxi", line 573, in lxml.etree._ParserContext._handleParseResultDoc (src\lxml\lxml.etree.c:103404)
  File "src/lxml/parser.pxi", line 683, in lxml.etree._handleParseResult (src\lxml\lxml.etree.c:105058)
  File "src/lxml/parser.pxi", line 613, in lxml.etree._raiseParseError (src\lxml\lxml.etree.c:103967)
XMLSyntaxError: Namespace prefix xsi for schemaLocation on Document is not defined, line 3, column 32

这是我的代码片段：(这应该是基于我的一个来源)

from pykml import parser

root = parser.fromstring(open('trim_KML.kml', 'r').read())
print etree.tostring(root.Document.Placemark.LineString.Description)

我已经安装了pykml和lxml 3.6.0，目前正在使用Python2.7.10。kml文件包含行。(kml链接：https://sites.google.com/site/kmlhostingmwss/trim.kml)我的ArcGIS 10.2中也有Python2.7。

我是新来处理kml文件的。有人能告诉我我做错了什么吗？还是有更简单的方法来编辑kml文件的描述？非常感谢。：))

Answer 1

xml存在一些问题，如果要删除错误，请将xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"添加到第二行：

<kml  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2" xmlns:kml="http://www.opengis.net/kml/2.2" xmlns:atom="http://www.w3.org/2005/Atom">

然后，使用lxml，可以实现以下工作：

import lxml.etree as et

xml = et.parse("trim.kml").getroot()

print(xml.xpath("//kml:Document//kml:Placemark/kml:description", namespaces={"kml":xml.nsmap["kml"]}))

这给了你：

[<Element {http://www.opengis.net/kml/2.2}description at 0x7f612d0885f0>, <Element {http://www.opengis.net/kml/2.2}description at 0x7f612d088cb0>, <Element {http://www.opengis.net/kml/2.2}description at 0x7f612d088d40>, <Element {http://www.opengis.net/kml/2.2}description at 0x7f612d088d88>, <Element {http://www.opengis.net/kml/2.2}description at 0x7f612d088dd0>, <Element {http://www.opengis.net/kml/2.2}description at 0x7f612d088e18>]

您还可以使用lxml.html，它可以更好地处理损坏的xml，数据本身也是99 %的html。

您可以通过以下方法从document.placemark内部获得一个：

from lxml import html
xml = html.parse("trim.kml")
print(xml.xpath("//placemark/description"))

这给了你：

[<Element description at 0x7f1c757fad08>, <Element description at 0x7f1c757fad60>, <Element description at 0x7f1c757fadb8>, <Element description at 0x7f1c757fae10>, <Element description at 0x7f1c757fae68>, <Element description at 0x7f1c757faec0>]