code: public void fillPolygon(double[]... coord) {
          int[][] c = new int[coord.length][2];
          for (int i = 0; i < coord.length; i++) {
              c[i] = projection.screenProjection(coord[i]);
          }
  
          int[] x = new int[c.length];
          for (int i = 0; i < c.length; i++) {
              x[i] = c[i][0];
          }
          int[] y = new int[c.length];
          for (int i = 0; i < c.length; i++) {
              y[i] = c[i][1];
          }
  
          g2d.fillPolygon(x, y, c.length);
      }
docs: Fill polygon. The coordinates are in logical coordinates.