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Dynamically adding a layer to the initial map

The following script shows how to create a temporary MapDefinition and insert a layer that is visible when the map loads. It can also be modified to toggle a layer's initial visibility.

Things to note

• The code assumes that you have already established a session
• The code can easily be used together with setting an intial map view
• $mdResourceId is the full resource id for the MapDefinition to use
• $rlLayerResourceId is the full resource id for the LayerDefintion to use
• $layerName is the name of the layer to insert

The code

<?php

//
// Vital includes.
//
$viewerDir = "mapviewerphp\\";
include $viewerDir . "constants.php";
include $viewerDir . "common.php";

// Build a string pointing to the new layer in the Session
$rlLayerResourceId = "Session:$sessionId//$layerName.LayerDefinition";

// Read the XML of the Library Map Definition
$mdReader = $resourceService->GetResourceContent($mdResourceId);
$mdXml = $mdReader->ToString();
$mdDomDoc = DOMDocument::loadXML($mdXml); 

// Create the MapLayer XML nodeset in the first position
$targetNode = $mdDomDoc->getElementsByTagName("MapLayer")->item(0);
$newNode = $targetNode->parentNode->insertBefore(new DOMElement("MapLayer"), $targetNode); 
$newNode->appendChild($mdDomDoc->createElement("Name", $layerName));
$newNode->appendChild($mdDomDoc->createElement("ResourceId", $rlLayerResourceId));
$newNode->appendChild($mdDomDoc->createElement("Selectable", "false"));
$newNode->appendChild($mdDomDoc->createElement("ShowInLegend", "false"));
$newNode->appendChild($mdDomDoc->createElement("LegendLabel"));
$newNode->appendChild($mdDomDoc->createElement("ExpandInLegend", "false"));
$newNode->appendChild($mdDomDoc->createElement("Visible", "true"));
$newNode->appendChild($mdDomDoc->createElement("Group"));

// Write the XML out to form the Session Map Definition
$mdUpdatedXml = $mdDomDoc->saveXML();
?>

See also

Setting an intial map view