[FEATURE]: possibility to set WMS featureInfo tolerance in request. Funded by city of Uster

Author: mhugent

src/server/qgswmsserver.cpp

@@ -1403,6 +1403,7 @@ int QgsWMSServer::getFeatureInfo( QDomDocument& result, QString version )
 
   QgsRectangle* featuresRect = 0;
   QgsPoint* infoPoint = 0;
+
   if ( i == -1 || j == -1 )
   {
     if ( mParameters.contains( "FILTER" ) )
@@ -1416,7 +1417,11 @@ int QgsWMSServer::getFeatureInfo( QDomDocument& result, QString version )
   }
   else
   {
-    infoPoint = new QgsPoint();
+      infoPoint = new QgsPoint();
+      if( !infoPointToMapCoordinates( i, j, infoPoint, mMapRenderer ) )
+      {
+          return 5;
+      }
   }
 
   //get the layer registered in QgsMapLayerRegistry and apply possible filters
@@ -1501,11 +1506,6 @@ int QgsWMSServer::getFeatureInfo( QDomDocument& result, QString version )
         continue;
       }
 
-      if ( infoPoint && infoPointToLayerCoordinates( i, j, infoPoint, mMapRenderer, currentLayer ) != 0 )
-      {
-        continue;
-      }
-
       //switch depending on vector or raster
       QgsVectorLayer* vectorLayer = dynamic_cast<QgsVectorLayer*>( currentLayer );
 
@@ -1552,7 +1552,12 @@ int QgsWMSServer::getFeatureInfo( QDomDocument& result, QString version )
         QgsRasterLayer* rasterLayer = dynamic_cast<QgsRasterLayer*>( currentLayer );
         if ( rasterLayer )
         {
-          if ( featureInfoFromRasterLayer( rasterLayer, infoPoint, result, layerElement, version, infoFormat ) != 0 )
+          if( !infoPoint )
+          {
+              continue;
+          }
+          QgsPoint layerInfoPoint = mMapRenderer->mapToLayerCoordinates( currentLayer, *infoPoint );
+          if ( featureInfoFromRasterLayer( rasterLayer, &layerInfoPoint, result, layerElement, version, infoFormat ) != 0 )
           {
             continue;
           }
@@ -1609,7 +1614,6 @@ int QgsWMSServer::getFeatureInfo( QDomDocument& result, QString version )
   restoreLayerFilters( originalLayerFilters );
   QgsMapLayerRegistry::instance()->removeAllMapLayers();
   delete featuresRect;
-  delete infoPoint;
   return 0;
 }
 
@@ -1916,38 +1920,18 @@ int QgsWMSServer::initializeSLDParser( QStringList& layersList, QStringList& sty
   return 0;
 }
 
-int QgsWMSServer::infoPointToLayerCoordinates( int i, int j, QgsPoint* layerCoords, QgsMapRenderer* mapRender,
-    QgsMapLayer* layer ) const
+bool QgsWMSServer::infoPointToMapCoordinates( int i, int j, QgsPoint* infoPoint, QgsMapRenderer* mapRenderer )
 {
-  if ( !layerCoords || !mapRender || !layer || !mapRender->coordinateTransform() )
+  if ( !mapRenderer || !infoPoint )
   {
-    return 1;
+    return false;
   }
 
-  //first transform i,j to map output coordinates
-  // toMapCoordinates() is currently (Oct 18 2012) using average resolution
-  // to calc point but GetFeatureInfo request may be sent with different
-  // resolutions in each axis
-  //QgsPoint mapPoint = mapRender->coordinateTransform()->toMapCoordinates( i, j );
-  double xRes = mapRender->extent().width() / mapRender->width();
-  double yRes = mapRender->extent().height() / mapRender->height();
-  QgsPoint mapPoint( mapRender->extent().xMinimum() + i * xRes,
-                     mapRender->extent().yMaximum() - j * yRes );
-
-  QgsDebugMsg( QString( "mapPoint (corner): %1 %2" ).arg( mapPoint.x() ).arg( mapPoint.y() ) );
-  // use pixel center instead of corner
-  // Unfortunately going through pixel (integer) we cannot reconstruct precisely
-  // the coordinate clicked on client and thus result may differ from
-  // the same raster loaded and queried locally on client
-  mapPoint.setX( mapPoint.x() + xRes / 2 );
-  mapPoint.setY( mapPoint.y() - yRes / 2 );
-
-  QgsDebugMsg( QString( "mapPoint (pixel center): %1 %2" ).arg( mapPoint.x() ).arg( mapPoint.y() ) );
-
-  //and then to layer coordinates
-  *layerCoords = mapRender->mapToLayerCoordinates( layer, mapPoint );
-  QgsDebugMsg( QString( "mapPoint: %1 %2" ).arg( mapPoint.x() ).arg( mapPoint.y() ) );
-  return 0;
+  double xRes = mapRenderer->extent().width() / mapRenderer->width();
+  double yRes = mapRenderer->extent().height() / mapRenderer->height();
+  infoPoint->setX( mapRenderer->extent().xMinimum() + i * xRes + xRes / 2.0 );
+  infoPoint->setY( mapRenderer->extent().yMaximum() - j * yRes - yRes / 2.0 );
+  return true;
 }
 
 int QgsWMSServer::featureInfoFromVectorLayer( QgsVectorLayer* layer,
@@ -1970,27 +1954,13 @@ int QgsWMSServer::featureInfoFromVectorLayer( QgsVectorLayer* layer,
   QgsRectangle mapRect = mapRender->extent();
   QgsRectangle layerRect = mapRender->mapToLayerCoordinates( layer, mapRect );
 
+
   QgsRectangle searchRect;
 
   //info point could be 0 in case there is only an attribute filter
   if ( infoPoint )
   {
-    double searchRadius = 0;
-    if ( layer->geometryType() == QGis::Polygon )
-    {
-      searchRadius = layerRect.width() / 400;
-    }
-    else if ( layer->geometryType() == QGis::Line )
-    {
-      searchRadius = layerRect.width() / 200;
-    }
-    else
-    {
-      searchRadius = layerRect.width() / 100;
-    }
-
-    searchRect.set( infoPoint->x() - searchRadius, infoPoint->y() - searchRadius,
-                    infoPoint->x() + searchRadius, infoPoint->y() + searchRadius );
+    searchRect = featureInfoSearchRect( layer, mapRender, renderContext, *infoPoint );
   }
   else if ( mParameters.contains( "BBOX" ) )
   {
@@ -3112,3 +3082,53 @@ int QgsWMSServer::getWMSPrecision( int defaultValue = 8 ) const
   }
   return WMSPrecision;
 }
+
+QgsRectangle QgsWMSServer::featureInfoSearchRect( QgsVectorLayer* ml, QgsMapRenderer* mr, const QgsRenderContext& rct, const QgsPoint& infoPoint ) const
+{
+  if ( !ml || !mr )
+  {
+    return QgsRectangle();
+  }
+
+  double mapUnitTolerance = 0.0;
+  if ( ml->geometryType() == QGis::Polygon )
+  {
+    QMap<QString, QString>::const_iterator tolIt = mParameters.find( "POLYGON_TOLERANCE" );
+    if ( tolIt != mParameters.constEnd() )
+    {
+      mapUnitTolerance = tolIt.value().toInt() * rct.mapToPixel().mapUnitsPerPixel();
+    }
+    else
+    {
+      mapUnitTolerance = mr->extent().width() / 400.0;
+    }
+  }
+  else if ( ml->geometryType() == QGis::Line )
+  {
+    QMap<QString, QString>::const_iterator tolIt = mParameters.find( "LINE_TOLERANCE" );
+    if ( tolIt != mParameters.constEnd() )
+    {
+      mapUnitTolerance = tolIt.value().toInt() * rct.mapToPixel().mapUnitsPerPixel();
+    }
+    else
+    {
+      mapUnitTolerance = mr->extent().width() / 200.0;
+    }
+  }
+  else //points
+  {
+    QMap<QString, QString>::const_iterator tolIt = mParameters.find( "POINT_TOLERANCE" );
+    if ( tolIt != mParameters.constEnd() )
+    {
+      mapUnitTolerance = tolIt.value().toInt() * rct.mapToPixel().mapUnitsPerPixel();
+    }
+    else
+    {
+      mapUnitTolerance = mr->extent().width() / 100.0;
+    }
+  }
+
+  QgsRectangle mapRectangle( infoPoint.x() - mapUnitTolerance, infoPoint.y() - mapUnitTolerance,
+                             infoPoint.x() + mapUnitTolerance, infoPoint.y() + mapUnitTolerance );
+  return( mr->mapToLayerCoordinates( ml, mapRectangle ) );
+}

src/server/qgswmsserver.h

@@ -134,13 +134,7 @@ class QgsWMSServer: public QgsOWSServer
     set to the layer and style names according to the SLD
     @return 0 in case of success*/
     int initializeSLDParser( QStringList& layersList, QStringList& stylesList );
-    /**Calculates the location of a feature info point in layer coordinates
-     @param i pixel x-coordinate
-    @param j pixel y-coordinate
-    @param layerCoords calculated layer coordinates are assigned to this point
-    @return 0 in case of success*/
-    int infoPointToLayerCoordinates( int i, int j, QgsPoint* layerCoords, QgsMapRenderer* mapRender,
-                                     QgsMapLayer* layer ) const;
+    static bool infoPointToMapCoordinates( int i, int j, QgsPoint* infoPoint, QgsMapRenderer* mapRenderer );
     /**Appends feature info xml for the layer to the layer element of the feature info dom document
     @param featureBBox the bounding box of the selected features in output CRS
     @return 0 in case of success*/
@@ -257,6 +251,9 @@ class QgsWMSServer: public QgsOWSServer
 
     /** Return precision to use for GetFeatureInfo request */
     int getWMSPrecision( int defaultValue ) const;
+
+    /**Gets layer search rectangle (depending on request parameter, layer type, map and layer crs)*/
+    QgsRectangle featureInfoSearchRect( QgsVectorLayer* ml, QgsMapRenderer* mr, const QgsRenderContext& rct, const QgsPoint& infoPoint ) const;
 };
 
 #endif