Datum transform dialog: show tooltip with transform code and src/dest…

… CRS description
qgis · Nov 25, 2013 · 0ca0d50 · 0ca0d50
1 parent fc115a4
commit 0ca0d50
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Showing 3 changed files with 47 additions and 0 deletions.
diff --git a/src/core/qgscoordinatetransform.cpp b/src/core/qgscoordinatetransform.cpp
@@ -932,6 +932,43 @@ QString QgsCoordinateTransform::datumTransformString( int datumTransform )
   return transformString;
 }
 
+bool QgsCoordinateTransform::datumTransformCrsInfo( int datumTransform, QString& srcProjection, QString& dstProjection )
+{
+  sqlite3* db;
+  int openResult = sqlite3_open( QgsApplication::srsDbFilePath().toUtf8().constData(), &db );
+  if ( openResult != SQLITE_OK )
+  {
+    sqlite3_close( db );
+    return false;
+  }
+
+  sqlite3_stmt* stmt;
+  QString sql = QString( "SELECT source_crs_code, target_crs_code FROM tbl_datum_transform WHERE coord_op_code = %1" ).arg( datumTransform );
+  int prepareRes = sqlite3_prepare( db, sql.toAscii(), sql.size(), &stmt, NULL );
+  if ( prepareRes != SQLITE_OK )
+  {
+    sqlite3_finalize( stmt ); sqlite3_close( db );
+    return false;
+  }
+
+  int srcCrsId, destCrsId;
+  if ( sqlite3_step( stmt ) == SQLITE_ROW )
+  {
+    srcCrsId = sqlite3_column_int( stmt, 0 );
+    destCrsId = sqlite3_column_int( stmt, 1 );
+  }
+
+  QgsCoordinateReferenceSystem srcCrs;
+  srcCrs.createFromOgcWmsCrs( QString( "EPSG:%1" ).arg( srcCrsId ) );
+  srcProjection = srcCrs.description();
+  QgsCoordinateReferenceSystem destCrs;
+  destCrs.createFromOgcWmsCrs( QString( "EPSG:%1" ).arg( destCrsId ) );
+  dstProjection = destCrs.description();
+
+  sqlite3_finalize( stmt ); sqlite3_close( db );
+  return true;
+}
+
 void QgsCoordinateTransform::addNullGridShifts( QString& srcProjString, QString& destProjString )
 {
   //if one transformation uses ntv2, the other one needs to be null grid shift

diff --git a/src/core/qgscoordinatetransform.h b/src/core/qgscoordinatetransform.h
@@ -214,6 +214,8 @@ class CORE_EXPORT QgsCoordinateTransform : public QObject
     /**Returns list of datum transformations for the given src and dest CRS*/
     static QList< QList< int > > datumTransformations( const QgsCoordinateReferenceSystem& srcCRS, const QgsCoordinateReferenceSystem& destCRS );
     static QString datumTransformString( int datumTransform );
+    /**Gets name of source and dest geographical CRS (to show in a tooltip)*/
+    static bool datumTransformCrsInfo( int datumTransform, QString& srcProjection, QString& dstProjection );
 
     int sourceDatumTransform() const { return mSourceDatumTransform; }
     void setSourceDatumTransform( int dt ) { mSourceDatumTransform = dt; }

diff --git a/src/gui/qgsdatumtransformdialog.cpp b/src/gui/qgsdatumtransformdialog.cpp
@@ -41,6 +41,14 @@ QgsDatumTransformDialog::QgsDatumTransformDialog( const QString& layerName, cons
       if ( nr != -1 )
       {
         item->setText( i, QgsCoordinateTransform::datumTransformString( nr ) );
+
+        //Describe datums in a tooltip
+        QString srcGeoProj, destGeoProj;
+        if ( QgsCoordinateTransform::datumTransformCrsInfo( nr, srcGeoProj, destGeoProj ) )
+        {
+          QString toolTipString = QString( "EPSG Transformations Code: %1\nSource CRS: %2\nDestination CRS: %3" ).arg( nr ).arg( srcGeoProj ).arg( destGeoProj );
+          item->setToolTip( i, toolTipString );
+        }
       }
 
       if ( gridShiftTransformation( item->text( i ) ) && !testGridShiftFileAvailability( item, i ) )