Unfolding Maps — mapDisplay.getOuterPG() is not working!

import processing.core.PApplet;
import processing.core.PGraphics;

import de.fhpotsdam.unfolding.UnfoldingMap;
import de.fhpotsdam.unfolding.providers.OpenStreetMap;
import de.fhpotsdam.unfolding.utils.MapUtils;


    private UnfoldingMap map;
    private PGraphics pg;

    private int n = 1000;

    public void setup() {

        size(n, n, P2D);
        map = new UnfoldingMap(this, new OpenStreetMap.OpenStreetMapProvider());
        MapUtils.createDefaultEventDispatcher(this, map);

    }

    public void draw() {

        background(0);
        pg = map.mapDisplay.getOuterPG();
        image(pg, 0, 0);

    }

Greetings! When I try to convert maps into PGraphics and display it, I see only black background :( Can anyone explain why it is so? Thank you!