Adding Layers To A Map

The preceding examples have created or modified the XML for layer definitions in memory. To add those layers to a map:

1. Save the layer definition to a resource stored in the session repository.
2. Add that resource to the map.

This function adds takes a layer’s XML, creates a resource in the session repository from it, and adds that layer resource to a map.

<?php
require_once('../common/common.php');
 
///////////////////////////////////////////////////////////
function add_layer_definition_to_map($layerDefinition,
  $layerName, $layerLegendLabel, $mgSessionId,
  $resourceService, &$map)
// Adds the layer definition (XML) to the map.
// Returns the layer.
{
    // Validate the XML.
    $domDocument = new DOMDocument;
    $domDocument->loadXML($layerDefinition);
    if (! $domDocument->schemaValidate(
       "$schemaDirectory\LayerDefinition-1.1.0.xsd") )
    {
        echo "ERROR: The new XML document is invalid.
          <BR>\n.";
        return NULL;
    }
    // Save the new layer definition to the session
    // repository
    $byteSource = new MgByteSource($layerDefinition,
      strlen($layerDefinition));
    $byteSource->SetMimeType(MgMimeType::Xml);
    $resourceID = new MgResourceIdentifier(
       "Session:$mgSessionId//$layerName.LayerDefinition");
    $resourceService->SetResource($resourceID,
      $byteSource->GetReader(), null);
    $newLayer = add_layer_resource_to_map($resourceID,
      $resourceService, $layerName, $layerLegendLabel,
      $map);
    return $newLayer;
}

This function adds a layer resource to a map.

function add_layer_resource_to_map($layerResourceID,
  $resourceService, $layerName, $layerLegendLabel, &$map)
// Adds a layer defition (which can be stored either in the
// Library or a session repository) to the map.
// Returns the layer.
{
    $newLayer = new MgLayer($layerResourceID,
      $resourceService);
    // Add the new layer to the map's layer collection
    $newLayer->SetName($layerName);
    $newLayer->SetVisible(true);
    $newLayer->SetLegendLabel($layerLegendLabel);
    $newLayer->SetDisplayInLegend(true);
    $layerCollection = $map->GetLayers();
    if (! $layerCollection->Contains($layerName) )
    {
        // Insert the new layer at position 0 so it is at
        // the top of the drawing order
        $layerCollection->Insert(0, $newLayer);
    }
    return $newLayer;
}

This function adds a layer to a legend’s layer group.

function add_layer_to_group($layer, $layerGroupName,
  $layerGroupLegendLabel, &$map)
// Adds a layer to a layer group. If necessary, it creates
// the layer group.
{
    // Get the layer group
    $layerGroupCollection = $map->GetLayerGroups();
    if ($layerGroupCollection->Contains($layerGroupName))
    {
        $layerGroup =
          $layerGroupCollection->GetItem($layerGroupName);
    }
    else
    {
        // It does not exist, so create it
        $layerGroup = new MgLayerGroup($layerGroupName);
        $layerGroup->SetVisible(true);
        $layerGroup->SetDisplayInLegend(true);
       
          $layerGroup->SetLegendLabel($layerGroupLegendLabel);
        $layerGroupCollection->Add($layerGroup);
    }
    // Add the layer to the group
    $layer->SetGroup($layerGroup);
}