Customers can draw the actual sketch size breakdown of the site according to the actual wall points on the site, especially the distance between columns and columns, and remove the dust, oil and other impurities on the surface of the columns before measurement to ensure the accuracy of measurement. Determine the measurement points of the column section as needed, these points can be the edges of the section, diameter, etc. Place the gauge on the designated measuring points, making sure that it is perpendicular to the cross-section. Carefully read the scale on the gauge and measure the diameter of the section. And record it for drawing the site plan.