读取多个.gpx文件 [英] Read multiple .gpx files

问题描述

假设我有许多 .gpx 文件(这些文件包含Garmin eTrex的GPX航点数据).我想用不同的名称将它们加载到R中并对其进行操作.

Suppose I have a number of .gpx files (these contain GPX waypoint data from a Garmin eTrex). I want to load them into R with different names and manipulate them.

我可以这样读取一个文件:

I can read one file thus:

library(maptools)
gpx.raw <- readGPS(i = "gpx", f = "file1_w_12_f_ddf.gpx", type="w")

假设我想将其中一些读入内存.我可以尝试 for 循环:

Suppose I want to read a number of them into memory. I could try a for loop:

files <- list.files(".",pattern = "*.gpx")
for(x in files){

    #Create new file name
    temp <- strsplit(x,"_",fixed=TRUE)
    visit.id <- sapply(temp,FUN=function(x){paste(x[1],x[4],substr(x[5],1,3),sep="_")})

    #read file with new filename
    assign(visit.id, readGPS(i = "gpx", f = x, type="w"))
}

在上述程序上运行会产生以下错误:

Running above program yields following error:

read.table(con<-textConnection(gpsdata)，fill = TRUE，...)中的错误: 输入中无行 另外:警告消息: 运行命令'C:\ PROGRA〜2 \ GPSBabel \ gpsbabel.exe -w -i gpx -f file1_w_12_f_ddf.gpx -o tabsep -F-'的状态为

Error in read.table(con <- textConnection(gpsdata), fill = TRUE, ...) : no lines available in input In addition: Warning message: running command 'C:\PROGRA~2\GPSBabel\gpsbabel.exe -w -i gpx -f file1_w_12_f_ddf.gpx -o tabsep -F -' had status 1

请注意，我能够自行读取此文件，因此似乎与文件本身无关，但与循环运行readGPS无关.

Note that I was able to read this file on its own, so it would seem it has nothing to do with the file itself but with running readGPS in a loop.

总的来说，我仍然感到非常困惑， R 如何处理上面的 x 之类的变量.我不确定如何修改独立实例f = "file1_w_12_f_ddf.gpx"中的readGPS参数:应该是x还是f = x或f = "x"，还是什么?也许问题出在给GPSBabel打电话...

In general I still find it very confusing how R treats variables like x above. I am not sure how to modify the argument to readGPS from the stand alone instance f = "file1_w_12_f_ddf.gpx": Should it be x, or f = x, or f = "x", or what? Or maybe the problem is in the call to GPSBabel...

我在下面提供了一个示例文件，因此您可以将其复制到文本编辑器中，并使用不同的名称另存为 .gpx..

I include a sample file below so you can copy it to text editor, and save as .gpx. twice with different names and try yourself.

<?xml version="1.0" encoding="UTF-8"?>
<gpx
 version="1.0"
 creator="GPSBabel - http://www.gpsbabel.org"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns="http://www.topografix.com/GPX/1/0"
 xsi:schemaLocation="http://www.topografix.com/GPX/1/0 http://www.topografix.com/GPX/1/0/gpx.xsd">
 <time>2010-09-14T18:35:43Z</time>
 <bounds minlat="18.149888897" minlon="-96.747799935" maxlat="50.982883293" maxlon="121.640266674"/>
<wpt lat="38.855549991" lon="-94.799016668">
<ele>325.049072</ele>
 <name>GARMIN</name>
 <cmt>GARMIN</cmt>
 <desc>GARMIN</desc>
 <sym>Flag</sym>
 </wpt>
 <wpt lat="50.982883293" lon="-1.463899976">
 <ele>35.934692</ele>
 <name>GRMEUR</name>
 <cmt>GRMEUR</cmt>
 <desc>GRMEUR</desc>
 <sym>Flag</sym>
 </wpt>
 <wpt lat="25.061783362" lon="121.640266674">
 <ele>38.097656</ele>
 <name>GRMTWN</name>
 <cmt>GRMTWN</cmt>
 <desc>GRMTWN</desc>
 <sym>Flag</sym>
 </wpt>
 </gpx>

注意:要运行 readGPS ，您将需要安装开源GPSBabel程序，并在PATH变量中引用该程序.

NOTE: To run readGPS you will need the open source GPSBabel program installed and referenced in your PATH variable.

推荐答案

原来的代码很好，问题出在文件名上. GPSBabel不喜欢带有空格的名称.因此，"1_SanJoséBaldi_Pernam_14_sep.gpx"是一个问题，而1_San_José_Baldi_Pernam_14_sep.gpx"不是问题.

Turns out the code was fine, the problem is with the file names. GPSBabel does not like names with white spaces. So "1_San José Baldi_Pernam_14_sep.gpx" is a problem, "1_San_José_Baldi_Pernam_14_sep.gpx" is not.

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