In the field expression enter "m ²" * "sum" and then click OK.Ī new field will now be visible in the table that represents the volume of each zone. Create a new field with the Output field name as volume the Output field type as Decimal number (double) ***this value may be different if your table was saved in a different format. To find a volume for each zone we will need to multiply the sum field and the m 2 field using the Field Calculator to create a new field with a volume calculated for each zone.Ĭlick on the Abacus icon at the top of the table or use the control-i command to open the field calculator. m 2 is the area of the zone and sum is the total elevation difference for all the cells/pixels in that specific zone. The zone field is the difference in elevation value that was calculated using the raster calculator. We are mainly interested in the zone, m 2, sum and count. Take a moment to view some of the values in the table and look at the field names to see what zonal statistics have automatically been calculated.
The table might take a minute to open depending on the size of your volume area and the resolution of the DEM. Right click on the zonal statistics table in the Layers Panel an select Open Attributes Table. group of raster cells with the same value). The resulting layer from the Raster Zonal Statistics was a new table with statistics and summaries for each raster zone (i.e. By following these 10 steps, you will be able to create a volume estimate from a LiDAR/UAV point cloud or a DEM.
The following is an advanced method tutorial that takes a step by step approach to answering these questions by using QGIS tools and elevation data from LiDAR and from UAVs/Drones to calculate volumes with centimeter precision. Some applications for these volume calculations are finding how much material is needed to fill a hole, how much volume will be extracted by mining an area to a certain depth, how much volume is in a pile of aggregate or finding how much material has been removed from an area. All that is required is elevation data from LiDAR or UAV photogrammetry in the form of point clouds which can then be converted into a Digital Elevation Model (DEM)/Digital Surface Model (DSM) as per this tutorial.
Surpac tutorial surface software#
It is a relatively simple process that can be performed with free and open source software in a few simple steps. Creation of contour lines of the collapse surface. Calculating volumes of earth, aggregate or holes over varying terrain is a challenging mathematical task that can have a huge impact on project budgets or predicted revenue. Surface analysis cuts (they can be performed in different directions: perpendicular to the side and in horizontal planes: in the first case, this is one of the main parameters for assessing the quality of the explosion and the location of the ore, in the other we get a topographic plan of the open pit).
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