Updating xml file with powershell-CodePudding

I'm trying to edit an XML file with Powershell. Specifically, a track in GPX format in which I want to correct the altitude coordinates of certain points, those corresponding to time after a certain moment (the time I changed the batteries to the GPS). This is the script with which I intend to do the update:

$filePath = "c:\users\g\documents\bat\PetroglifosV.gpx"
$xml = [xml] (Get-Content $filePath)
$nodes = $xml.SelectNodes("//trkpt")
# Write-Host "Tratando: " $nodes
foreach ($element in $nodes) {
   Write-Host "Tratando elemento: " $element.ele.InnerText
   if ($element.time.InnerText.Substring(11,5) -gt "08:48") { $element.ele.InnerText = 217   $element.ele.InnerText }
   Write-Host "Tratado elemento: " $element.ele.InnerText
   }
$xml.Save("c:\users\g\documents\bat\petrotemp.txt")

And this is the XML file:

<?xml version="1.0" encoding="UTF-8"?>
<gpx creator="Wikiloc - https://www.wikiloc.com" version="1.1" xmlns="http://www.topografix.com/GPX/1/1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd">
  <metadata>
    <name>Wikiloc - Baiona a los petroglifos de Outeiro dos Lameiros</name>
    <author>
      <name>guigargi</name>
      <link href="https://www.wikiloc.com/wikiloc/user.do?id=657054">
        <text>guigargi on Wikiloc</text>
      </link>
    </author>
    <link href="https://www.wikiloc.com/hiking-trails/baiona-a-los-petroglifos-de-outeiro-dos-lameiros-26925951">
      <text>Baiona a los petroglifos de Outeiro dos Lameiros on Wikiloc</text>
    </link>
    <time>2018-07-23T09:55:48Z</time>
  </metadata>
  <trk>
    <name>Baiona a los petroglifos de Outeiro dos Lameiros</name>
    <cmt>
    </cmt>
    <desc>
    </desc>
    <trkseg>
      <trkpt lat="42.117677" lon="-8.847421">
        <ele>-12.431</ele>
        <time>2018-07-23T06:55:22Z</time>
      </trkpt>
      <trkpt lat="42.117649" lon="-8.847403">
        <ele>-12.461</ele>
        <time>2018-07-23T06:55:23Z</time>
      </trkpt>
      <trkpt lat="42.117661" lon="-8.847388">
        <ele>-12.407</ele>
        <time>2018-07-23T06:55:24Z</time>
      </trkpt>
      <trkpt lat="42.117687" lon="-8.847385">
        <ele>-12.408</ele>
        <time>2018-07-23T06:57:09Z</time>
      </trkpt>
      <trkpt lat="42.117593" lon="-8.847370">
        <ele>-12.435</ele>
        <time>2018-07-23T06:57:25Z</time>
      </trkpt>
      <trkpt lat="42.113513" lon="-8.838031">
        <ele>-184.594</ele>
        <time>2018-07-23T09:55:38Z</time>
      </trkpt>
      <trkpt lat="42.113517" lon="-8.838084">
        <ele>-184.520</ele>
        <time>2018-07-23T09:55:48Z</time>
      </trkpt>
    </trkseg>
  </trk>
</gpx>

It seems to me that it does not enter the FOR EACH loop, I guess because the $NODES array has nothing. The SAVE order seems work fine.

Can anyone help me. Thank you

GGG

CodePudding user response：

You are comparing strings against strings, but what you need to do is compare TimeSpan objects against each other.

Try

# load the xml file. This way, you are ensured to get the file encoding correct
$xml = [System.Xml.XmlDocument]::new()
$xml.Load('c:\users\g\documents\bat\PetroglifosV.gpx')

# create a TimeSpan object to match the XML <time> elements against
$compareTime = [TimeSpan]::new(8,48,0)  # Hours, Minutes, Seconds

$nodes = $xml.DocumentElement.trk.trkseg.trkpt
foreach ($element in $nodes) {
   Write-Host "Tratando elemento: $($element.ele)"
   # the dates in the XML are given as UTC, so you probably want ToUniversalTime()
   $time = ([datetime]$element.time).ToUniversalTime().TimeOfDay  # --> convert into a TimeSpan object
   # compare the TimeSpan objects
   if ($time -gt $compareTime) { 
        $value = [double]$element.ele   217
        $element.ele = "$value"
        Write-Host "Tratado elemento: $($element.ele)"
   }
}

$xml.Save('c:\users\g\documents\bat\petrotemp.xml')

CodePudding user response：

Here is similar solution

using assembly System 
using assembly System.Xml.Linq 

$filename = "c:\temp\test.xml"
$xDoc = [System.Xml.Linq.XDocument]::Load($filename)
$root = [System.Xml.Linq.XElement]$xDoc.Root
$ns = [System.Xml.Linq.XNamespace]$root.GetDefaultNamespace()
$times = $root.Descendants($ns   "time")
foreach($time in $times)
{

   $date = [DateTime]$time.Value
   if ($date.TimeOfDay -gt [TimeSpan]::Parse("08:48"))
   {
      $time.Value = (217   $date.Ticks).Value
   }
}