Displaying Mouse Coordinates in a QGIS + Qt Application

/ GIS, QGIS
qgis-mouse-coordinate-display-manya-technologies

When building custom GIS applications using the QGIS API and Qt, it’s often useful to show the current mouse coordinates on the map canvas. A common place to display this information is in the status bar.

In this post, we’ll look at a minimal example of how to connect the QGIS map canvas (QgsMapCanvas) to a status bar widget and display real-time coordinates.

Minimal Implementation

We only need to connect the xyCoordinates signal from the canvas to a slot that updates a QLineEdit (or any other text display widget):

void StatusBarCoordinatesWidget::setMapCanvas( QgsMapCanvas *mapCanvas )
{
    if ( mMapCanvas )
    {
        disconnect( mMapCanvas, &QgsMapCanvas::xyCoordinates,
                    this, &StatusBarCoordinatesWidget::showMouseCoordinates );
    }

    mMapCanvas = mapCanvas;

    connect( mMapCanvas, &QgsMapCanvas::xyCoordinates,
             this, &StatusBarCoordinatesWidget::showMouseCoordinates );
}

void StatusBarCoordinatesWidget::showMouseCoordinates( const QgsPointXY &point )
{
    if ( point.isEmpty() )
    {
        mLineEdit->clear();
        return;
    }

    QString coordText = QgsCoordinateUtils::formatCoordinateForProject(
                            QgsProject::instance(),
                            point,
                            mMapCanvas->mapSettings().destinationCrs(),
                            static_cast<int>( mMousePrecisionDecimalPlaces ) );

    mLineEdit->setText( coordText );
}

How It Works

  • setMapCanvas()
    Connects the QgsMapCanvas::xyCoordinates signal to our slot.
  • showMouseCoordinates()
    Directly receives the current mouse position (QgsPointXY) and updates the status bar with properly formatted coordinates.

That’s it — no extra member variables or methods needed.

Example Output

When the mouse moves across the map:

X: 77.5946   Y: 12.9716

These values update instantly in the status bar.

Conclusion

By directly connecting the QGIS map canvas signal to a status bar widget, we can create a clean and efficient coordinate display with very little code.

This pattern is also extendable — for example, you can:

  • Add multiple coordinate formats (WGS84 + Project CRS).
  • Allow copying coordinates with a right-click menu.
  • Display additional context like elevation or map scale.

If you’re interested in a full-fledged GIS solution, check out our flagship product PrithviGIS – a powerful QGIS-based platform for real-time geospatial visualization.

For collaboration, demos, or project discussions, feel free to contact Manya Technologies.

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