def pixel_bounds_based_on_center
      viewport_radius_w = @viewport_w / 2
      viewport_radius_h = @viewport_h / 2
      @pixel_bounds_based_on_center ||= {
          sw: [pixel_coords[0] + viewport_radius_h, pixel_coords[1] - viewport_radius_w],
          ne: [pixel_coords[0] - viewport_radius_h, pixel_coords[1] + viewport_radius_w]
      }
    end
def pixel_bounds_based_on_center
      viewport_radius_w = @viewport_w / 2
      viewport_radius_h = @viewport_h / 2
      @pixel_bounds_based_on_center ||= {
          sw: [pixel_coords[0] + viewport_radius_h, pixel_coords[1] - viewport_radius_w],
          ne: [pixel_coords[0] - viewport_radius_h, pixel_coords[1] + viewport_radius_w]
      }
    end
Return: pixel bounds of the viewport
 PS: Top Left is 0,0
     in pixel coords, lat long increase => farther from 0,0