Hi,
if you have access to the mapfile, you can make a queryByPoint with
mapscript (i.e with an ajax-function)
You have to send your point-coordinats to the script like this:
$coord = split(',',$_POST["coord"]);
dl('php_mapscript.dll');
//load mapfile
$map= ms_newMapObj($mapfilepath.'\yourmap.map');
//create point
$qPoint = ms_newPointObj();
$qPoint->setXY($coord[0]*1,$coord[1]*1);
//set layer
$layer = $map->getLayerByName("your_rasterlayer");
//Pointquery (Single)
@$datQuery = $layer->queryByPoint($qPoint, MS_SINGLE, 1);
//if success
if ($datQuery == MS_SUCCESS) {
for ($j=0; $j<$layer->getNumResults(); $j++) {
$result = $layer->getResult($j);
$layer->open();
$shpobj = $layer->getShape($result->tileindex,$result->shapeindex);
$attr = $shpobj->values;
//echo round($attr["value_0"],2);
$rasterdata = round($attr["value_0"],1);
print 'My Data: '.$rasterdata.';
$shpobj->free();
}
}
else{
print 'no Data';
}
Greetings
Sven
----- Original Message -----
From: "Andrew Mason" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, May 29, 2008 10:29 AM
Subject: [mapserver-users] Accessing raster cell values
Hello List,
This question may be a general newbie GIS question and not solely related
to Mapserver, so apologies if I'm posting to the wrong place.
I am serving a GeoTiff via Mapserver using WMS, and displaying it using
OpenLayers, so far so good.
I need to be able to click on a point on the map and display the value
held within that particular Raster cell.
Can anyone suggest what mechanism I should use for this? WCS looks like
it might be the thing I need, but I'm having difficulty finding much in
the way of examples and instructions.
I've followed what examples there are and all I can get Mapserver to
return using WCS, is a Geotiff with every pixel set to zero.
So I've obviously not got it working correctly, and even if it were I'm
not sure how to get the information I need out of the returned Geotiff
when my client is OpenLayers.
Can anyone suggest a way to access a raster's values when it is served by
Mapserver and viewed using OpenLayers?
Thank you
Andrew Mason
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