@Nullable
    @Override
    public Viewport getViewport() {
        if (viewport == null && !viewportTried) {
            viewportTried = true;
            final Viewport.ContainingViewportBuilder builder = new Viewport.ContainingViewportBuilder();
            calculateViewport(builder, this);
            viewport = builder.getViewport();
        }
        return viewport;
    }
Represents a group of drawable GeoItem such as a point, polyline, polygon or enclosed groups
main/src/main/java/cgeo/geocaching/models/geoitem/GeoGroup.java