1. Print the Site Plan : Print a copy of the site plan ensure it has existing and proposed levels defined. These are known as ‘grading plans’
2. Decide on the units and scale of your Grid Squares : My plan is in metric units so I have used centimetres (cm) for the grid. It should be written on the plan what scale it is. You need to decide how large you want each grid cell to be and then calculate using the scale the dimensions of the grid squares in paper space. For instance if the plan is 1:200 and you want grid squares of 0.5m in the real world then your grid squares will need to be 2.5cm in paper space as 2.5cm x 200 = 500cm (0.5m).
When you are deciding the size of your grid squares, it is important to consider the trade off between dense grids that are more accurate but are potentially very time consuming to complete and larger grids that are less accurate and faster. This topic is discussed in more detail in the article : How Accurate is the Grid Method For Calculating Earthworks Cut & Fill Volumes?
3. Draw the grid : Once you have established the size of each cell you need to draw a grid over your whole site. A roller ruler can be a handy tool for this but a standard ruler works just fine also.
Rather than drawing a grid directly over the site plan it is a good idea to do it over an semi transparent sheet like acetate. This way you can make mistakes and don’t have to print another site plan. Another options is to print the grid by downloading a template offline.
4. Label the Grid Lines : You also need to label the X axis lines (not the cells) from A – Z and the Y axis lines from 1 ..2…3 so the cells correlate to cells in the spreadsheet we are using to do the calculations.
