function getElevation($lat, $lng, $source)
{
$msg = "";
switch ($source) {
case "gmaps":
$url = "http://maps.google.com/maps/api/elevation/xml?locations=" . $lat . "," . $lng . "&sensor=false";
if (!($dom = @domxml_open_file($url))) {
die("Error opening xml file");
}
$xpath = @xpath_new_context($dom);
if ($_lat = @xpath_eval_expression($xpath, '//location/lat/text()')) {
$_lat = $_lat->nodeset[0]->node_value();
}
if ($_lng = @xpath_eval_expression($xpath, '//location/lng/text()')) {
$_lng = $_lng->nodeset[0]->node_value();
}
if ($alt = @xpath_eval_expression($xpath, '//elevation/text()')) {
$alt = $alt->nodeset[0]->node_value();
$msg = "";
} else {
if ($msg = @xpath_eval_expression($xpath, '//status/text()')) {
$msg = $msg->nodeset[0]->node_value();
}
}
$ds = '';
break;
case "usgs":
$url = "http://gisdata.usgs.gov/xmlwebservices2/elevation_service.asmx/getElevation?X_Value=" . $lng . "&Y_Value=" . $lat . "&Elevation_Units=METERS&Source_Layer=-1&Elevation_Only=-1";
//$dom = @domxml_open_file($url);
if (!($dom = @domxml_open_file($url))) {
die("Error opening xml file");
}
$xpath = @xpath_new_context($dom);
if ($_lat = @xpath_eval_expression($xpath, '//Y_Value/text()')) {
$_lat = $_lat->nodeset[0]->node_value();
}
if ($_lng = @xpath_eval_expression($xpath, '//X_Value/text()')) {
$_lng = $_lng->nodeset[0]->node_value();
}
//if ($alt = @xpath_eval_expression($xpath, '//Elevation/text()')) {
if ($alt = @xpath_eval_expression($xpath, '//Elevation_Only/text()')) {
$alt = $alt->nodeset[0]->node_value();
$msg = "";
} else {
if ($msg = @xpath_eval_expression($xpath, '//Elevation_Query/text()')) {
$msg = $msg->nodeset[0]->node_value();
}
}
//if ($ds = @xpath_eval($xpath, '//Data_Source/text()')) {
if ($ds = @xpath_eval_expression($xpath, '//Source_Layer/text()')) {
$ds = $ds->nodeset[0]->node_value();
}
break;
case "geonames":
$url = "http://ws.geonames.org/srtm3?lat=" . $lat . "&lng=" . $lng . "&style=full&type=XML";
//$dom = @domxml_open_file($url);
if (!($dom = @domxml_open_file($url))) {
die("Error opening xml file");
}
$xpath = @xpath_new_context($dom);
if ($_lat = @xpath_eval_expression($xpath, '//lat/text()')) {
$_lat = $_lat->nodeset[0]->node_value();
}
if ($_lng = @xpath_eval_expression($xpath, '//lng/text()')) {
$_lng = $_lng->nodeset[0]->node_value();
}
if ($alt = @xpath_eval_expression($xpath, '//srtm3/text()')) {
$alt = $alt->nodeset[0]->node_value();
$alt = $alt == '-32768' ? 0 : $alt;
$msg = "";
}
/* else {
if ($msg = @xpath_eval_expression($xpath, '//Elevation_Query/text()')) {
$msg = $msg->nodeset[0]->node_value();
}
}*/
$ds = 'SRTM3';
break;
default:
exit;
}
return array("lat" => $_lat, "lng" => $_lng, "alt" => $alt, "src" => $ds, "msg" => $msg, "url" => $url);
}
function SelectNodes($query)
{
if (EWRPT_IS_PHP5) {
$xpath = new DOMXPath($this->XmlDoc);
return $xpath->query($query);
} else {
$xpath = xpath_new_context($this->XmlDoc);
$xpathobj = xpath_eval_expression($xpath, $query);
return $xpathobj->nodeset;
}
}