如何获取从svg文件到R的路径的坐标 [英] How to get coordinates of a path from svg file into R
问题描述
也许这是一个愚蠢的问题,但是我没有很多经验.我需要从多边形中获取坐标以在R中创建轮廓.它是大约1000个点的复杂多边形,因此手动输入坐标太疯狂了.另外,我需要提取轮廓内某些对象的xy位置. 我试图使用Illustrator和Inkscape创建一个包含所有信息的svg文件.考虑到svg文件包含所有信息,这似乎是一个不错的选择.有没有一种方法可以从路径或多边形点中提取坐标?还是有其他更简单的方法来执行此过程? 我将非常感谢您的帮助,因为我必须处理大约30张图像. 干杯
May be it is a silly question but I don't have a lot of experience doing this. I need to get the coordinates from a polygon to create a contour in R. It is a complex polygon of about 1000 points so to input the coordinates manually is crazy. Also I need to extract the xy position of some objects inside the contour. I tried to use Illustrator and Inkscape to create an svg file that contains all the information. It looks like a good option considering that the svg file contains all the information. Is there a way to extract the coordinates from the path or polygon nods? or there is any other simpler way to do this process? I will really appreciate any help because I have to do it for around 30 images. Cheers
推荐答案
您可以使用XML
包提取坐标.
You can use the XML
package to extract the coordinates.
# Sample data
library(RCurl)
url <- "http://upload.wikimedia.org/wikibooks/en/a/a8/XML_example_polygon.svg"
svg <- getURL(url)
# Parse the file
library(XML)
doc <- htmlParse(svg)
# Extract the coordinates, as strings
p <- xpathSApply(doc, "//polygon", xmlGetAttr, "points")
# Convert them to numbers
p <- lapply( strsplit(p, " "), function(u)
matrix(as.numeric(unlist(strsplit(u, ","))),ncol=2,byrow=TRUE) )
p
但是,这忽略了要应用于多边形的任何变换.
However, this ignores any transformation to be applied to the polygon.
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