KML到CSV（Google Earth到Agisoft Photoscan Pro）

Question

I am trying to write a script to convert Google Earth KML files to CSV files for use in Agisoft's Photoscan Pro. This script will enable users to quickly create a CSV file of GCPs (Ground Control Points) for the optimization of models so they can be more accurately overlaid in Google Earth.

How do I write this to a CSV?

<?php

    $inputfile = simplexml_load_file('Points.kml');
    $placemarks = $inputfile->Document->Folder->Placemark;

    print "<pre>";
    print_r($inputfile->Document->Folder->Placemark[0]);

    foreach ($placemarks as $placemark){
        $name = $placemark->name;
        $longitude = $placemark->LookAt->longitude;
        $latitude = $placemark->LookAt->latitude;
        $altitude = $placemark->LookAt->altitude;
        //print $name.",".$longitude.",".$latitude.",".$altitude;
        //print "</br>";
        $array = array("$name", "$longitude", "$latitude", "$altitude");
        //var_dump($array);
    }
?>

Example KML:

<?xml version="1.0" encoding="UTF-8"?>
<kml 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">
<Document>
    <name>Points.kml</name>
    <Style id="sn_open-diamond">
        <IconStyle>
            <color>ff0e12b7</color>
            <scale>0.7</scale>
            <Icon>
                <href>http://maps.google.com/mapfiles/kml/shapes/open-diamond.png</href>
            </Icon>
        </IconStyle>
        <LabelStyle>
            <color>b30e12b7</color>
        </LabelStyle>
    </Style>
    <StyleMap id="msn_open-diamond">
        <Pair>
            <key>normal</key>
            <styleUrl>#sn_open-diamond</styleUrl>
        </Pair>
        <Pair>
            <key>highlight</key>
            <styleUrl>#sh_open-diamond</styleUrl>
        </Pair>
    </StyleMap>
    <Style id="sh_open-diamond">
        <IconStyle>
            <color>ff0e12b7</color>
            <scale>0.827273</scale>
            <Icon>
                <href>http://maps.google.com/mapfiles/kml/shapes/open-diamond.png</href>
            </Icon>
        </IconStyle>
        <LabelStyle>
            <color>b30e12b7</color>
        </LabelStyle>
    </Style>
    <Folder>
        <name>Points</name>
        <open>1</open>
        <Placemark>
            <name>1</name>
            <LookAt>
                <longitude>-81.11867631881405</longitude>
                <latitude>28.58871312454101</latitude>
                <altitude>0</altitude>
                <heading>1.04958304488296e-13</heading>
                <tilt>0</tilt>
                <range>16</range>
                <gx:altitudeMode>relativeToSeaFloor</gx:altitudeMode>
            </LookAt>
            <styleUrl>#msn_open-diamond</styleUrl>
            <Point>
                <gx:drawOrder>1</gx:drawOrder>
                <coordinates>-81.11867631881405,28.58871312454101,0</coordinates>
            </Point>
        </Placemark>
        <Placemark>
            <name>2</name>
            <LookAt>
                <longitude>-81.11878160604603</longitude>
                <latitude>28.58868018607449</latitude>
                <altitude>0</altitude>
                <heading>-5.038190918931147e-05</heading>
                <tilt>0</tilt>
                <range>16.00000207857145</range>
                <gx:altitudeMode>relativeToSeaFloor</gx:altitudeMode>
            </LookAt>
            <styleUrl>#msn_open-diamond</styleUrl>
            <Point>
                <gx:drawOrder>1</gx:drawOrder>
                <coordinates>-81.11878160604603,28.58868018607449,0</coordinates>
            </Point>
        </Placemark>
        <Placemark>
            <name>3</name>
            <LookAt>
                <longitude>-81.11889392441689</longitude>
                <latitude>28.58897376333365</latitude>
                <altitude>0</altitude>
                <heading>-5.676793149912727e-05</heading>
                <tilt>0</tilt>
                <range>16</range>
                <gx:altitudeMode>relativeToSeaFloor</gx:altitudeMode>
            </LookAt>
            <styleUrl>#msn_open-diamond</styleUrl>
            <Point>
                <gx:drawOrder>1</gx:drawOrder>
                <coordinates>-81.11889392441689,28.58897376333365,0</coordinates>
            </Point>
        </Placemark>
        <Placemark>
            <name>4</name>
            <LookAt>
                <longitude>-81.11879074625233</longitude>
                <latitude>28.58900436190265</latitude>
                <altitude>0</altitude>
                <heading>-7.3948102396262e-06</heading>
                <tilt>0</tilt>
                <range>16.00000167331963</range>
                <gx:altitudeMode>relativeToSeaFloor</gx:altitudeMode>
            </LookAt>
            <styleUrl>#msn_open-diamond</styleUrl>
            <Point>
                <gx:drawOrder>1</gx:drawOrder>
                <coordinates>-81.11879074625233,28.58900436190265,0</coordinates>
            </Point>
        </Placemark>
    </Folder>
</Document>
</kml>

Example CSV:

# Label,X,Y,Z
1,-81.11867632,28.58871312,0
2,-81.11878161,28.58868019,0
3,-81.11889392,28.58897376,0

Answer 1

simplexml_load_file will return SimpleXMLElement class, so you should use method from this class to access to xml elements.

For example children method - http://www.php.net/manual/en/simplexmlelement.children.php