改变iGraph中图顶点的X和Y坐标
我正在使用改变iGraph中图顶点的X和Y坐标,r,igraph,graph-theory,R,Igraph,Graph Theory,我正在使用igraph包来绘制我在yEd中创建的图形。这是一个应该覆盖在地理地图上的图形,所以我想做的第一件事就是改变顶点坐标,使它们与它们所代表的经度/纬度相匹配。(简单线性变换) 我尝试使用GraphML格式,但iGraph无法读取由yEd创建的GraphML文件,因此,我将该图形保存为GML文件。顶点信息的结构如下所示: node [ id 0 label "" graphics [ x 2181.0043222386603
igraph
包来绘制我在yEd中创建的图形。这是一个应该覆盖在地理地图上的图形,所以我想做的第一件事就是改变顶点坐标,使它们与它们所代表的经度/纬度相匹配。(简单线性变换)
我尝试使用GraphML格式,但iGraph无法读取由yEd创建的GraphML文件,因此,我将该图形保存为GML文件。顶点信息的结构如下所示:
node [
id 0
label ""
graphics [
x 2181.0043222386603
y 1463.6747524664843
w 5.2609883750396875
h 5.1510372122625085
type "ellipse"
raisedBorder 0
fill "#FFCC00"
outline "#000000"
]
]
library(igraph)
g <- read_graph("graph.gml", format="gml") #create graph object
z <- readLines("graph.gml") #create character vector from which to grep out attributes
id <- trimws(gsub("\t\tid\t", " ", z[grep("\t\tid\t", z)])) #retrive node ids
totid <- length(id) #retrieve number of nodes
#grep for and extract x and y attributes
xcor <- as.numeric(trimws(gsub("\t\t\tx\t", " ", z[grep("\t\t\tx\t", z)])))[1:totid]
ycor <- as.numeric(trimws(gsub("\t\t\ty\t", " ", z[grep("\t\t\ty\t", z)])))[1:totid]
#edges will also have x and y coordinates, so we need to index by the number of nodes
#add attributes back into graph object
g <- set.vertex.attribute(g, "x", value=xcor)
g <- set.vertex.attribute(g, "y", value=ycor)
如您所见,坐标保存在graphics
属性中。这是有效的GML语法(至少是AFAIK)。但是,load\u graph
无法正确处理此属性,并且iGraph不会保存坐标。当我尝试提取顶点属性时,我得到以下结果:
> vertex_attr(g) %>% glimpse()
# List of 3
# $ id : num [1:73] 0 1 2 3 4 5 6 7 8 9 ...
# $ label : chr [1:73] "" "" "" "" ...
# $ graphics: chr [1:73] "qÑÜ\020#8" "qÑÜ\020#8" "qÑÜ\020#8" "qÑÜ\020#8" ...
如何正确加载图形,包括x和y坐标?从
igraph
中,它指出其读取GML
能力的限制之一是
仅使用节点和边属性,并且仅当它们具有简单的
类型:整数、实数或字符串。因此,如果属性是数组或
记录,则忽略它。如果只有
属性是复杂的
这可能就是为什么它在图形
属性上遇到问题的原因igraph
也应该能够读取graphml
格式,但可能会遇到同样的障碍
幸运的是,如果您需要一种变通方法,GML
是一种人类可读的格式,比较容易解析。例如,如果只需要节点的x
和y
坐标,可以执行以下操作:
node [
id 0
label ""
graphics [
x 2181.0043222386603
y 1463.6747524664843
w 5.2609883750396875
h 5.1510372122625085
type "ellipse"
raisedBorder 0
fill "#FFCC00"
outline "#000000"
]
]
library(igraph)
g <- read_graph("graph.gml", format="gml") #create graph object
z <- readLines("graph.gml") #create character vector from which to grep out attributes
id <- trimws(gsub("\t\tid\t", " ", z[grep("\t\tid\t", z)])) #retrive node ids
totid <- length(id) #retrieve number of nodes
#grep for and extract x and y attributes
xcor <- as.numeric(trimws(gsub("\t\t\tx\t", " ", z[grep("\t\t\tx\t", z)])))[1:totid]
ycor <- as.numeric(trimws(gsub("\t\t\ty\t", " ", z[grep("\t\t\ty\t", z)])))[1:totid]
#edges will also have x and y coordinates, so we need to index by the number of nodes
#add attributes back into graph object
g <- set.vertex.attribute(g, "x", value=xcor)
g <- set.vertex.attribute(g, "y", value=ycor)
库(igraph)
g感谢提供文档链接。似乎编写自己的解析器将是这里唯一的解决方案。如果我要这样做,我将为GraphML文件编写一个解析器,因为它们基于XML结构。