I'm trying to grab the coordinates from .kml files that look something like this:
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.0">
<Document>
<name>Name</name><Style id="roadStyle"><LineStyle><color>7fcf0064</color><width>6</width></LineStyle></Style><Snippet><![CDATA[<font size=+1><a href="http://example.com/">Printable view</a></font>]]></Snippet>
<Placemark>
<name>Example</name>
<description><![CDATA[example]]></description><address>100 Example St</address><StyleMap><Pair><key>normal</key><Style><IconStyle><Icon><href>http://example.com</href></Icon><hotSpot x="0.000000" y="0.000000" xunits="fraction" yunits="fraction" /></IconStyle><ListStyle><ItemIcon><href>http://example.com</href></ItemIcon></ListStyle></Style></Pair><Pair><key>highlight</key><Style><IconStyle><scale>1.000000</scale><Icon><href>http://example.com</href></Icon><hotSpot x="0.000000" y="0.000000" xunits="fraction" yunits="fraction" /></IconStyle><ListStyle><ItemIcon><href>http://example.com</href></ItemIcon></ListStyle></Style></Pair></StyleMap><Point><coordinates>0.000000,0.000000,0</coordinates></Point><LookAt><longitude>0.000000</longitude><latitude>0.000000</latitude><range>100.000000</range><tilt>45.000000</tilt><heading>0.000000</heading></LookAt>
</Placemark>
<Placemark>
<name>Route</name>
<description><![CDATA[Example]]></description>
<GeometryCollection>
<LineString>
<coordinates>0.000000,0.000000,0.000000 0.000000,0.000000,0.000000 0.000000,0.000000,0.000000 0.000000,0.000000,0.000000 0.000000,0.000000,0.000000 0.000000,0.000000,0.000000 0.000000,0.000000,0.000000</coordinates>
</LineString>
</GeometryCollection>
<styleUrl>#roadStyle</styleUrl>
</Placemark>
</Document>
</kml>
I'm trying to use QXmlQuery to retrieve the coordinates with an XPath string similar to this:
kml/Document/Placemark[last()]/GeometryCollection/LineString/coordinates
I've tested that here and confirmed it works, so far so good. But I've had a horrible time getting it to work in Qt. I've tried a lot of things, including suggestions in other posts here on SO, without luck. Here's a couple examples showing the variations:
void testQuery1(QString &filename) {
QXmlQuery query;
query.bindVariable("kmlFile", QVariant(filename));
query.setQuery("declare default element namespace \"http://earth.google.com/kml/2.0\"; declare variable $kmlFile external; doc($kmlFile)//coordinates");
QStringList results;
query.evaluateTo(&results);
qDebug() << results.size();
}
void testQuery2(QString &filename) {
QFile file(filename);
file.open(QIODevice::ReadOnly);
QXmlQuery query;
query.setFocus(&file);
query.setQuery("kml/Document/Placemark[last()]/GeometryCollection/LineString/coordinates");
QString result;
query.evaluateTo(&result);
qDebug() << result;
}
I get 0
and " \n"
from each of those, respectively. Where am I going wrong here and what do I need to do to fix it? I'm open to other approaches as long as they stay within Qt (I'm using 4.7) and standard C++.
After much experimentation, I seem to have hit upon the magic recipe:
void testQuery(QString &filename) {
QFile file(filename);
file.open(QIODevice::ReadOnly);
QXmlQuery query;
query.bindVariable("kmlFile", &file);
query.setQuery("declare default element namespace \"http://earth.google.com/kml/2.0\"; declare variable $kmlFile external; doc($kmlFile)/kml/Document/Placemark[last()]/GeometryCollection/LineString/coordinates/text()");
QString result;
query.evaluateTo(&result);
qDebug() << result;
file.close();
}
That gives me my string of zeroes (or whatever the coordinates may be).