Landfill sites, quarries and other similiar properties are ideal candidates for drone surveys in light of the nature of the topography. A drone survey can be undertaken in much shorter time and with miniminal disruption to site operations. Furthermore the data outputs can be processed quickly providing the client with a cost effective solution. In this and other similar surveys we have undertaken the comparable time for a traditional survey is at least 5 times longer on site (one project was estimated at 7 working days with 2 men) and that is with multiple personnel teams.
For surveys such as this we usually provide the clients with a range of outputs. The survey is provided as a DSM, DSM Hillshade, DTM, Contours and Point Clouds. In addition we take an appropriate number of aerial stills and video. These are both good reference material for the client to use. For this project the data is required to help ascertain the remaining voidspace at the site.
We are often asked about the accuracy of drone derived data. Photogrammetry derived data for cases such as this requires the use of ground controls to fix the location of the imagery. Drone surveys are not as accurate as traditional survey techniques but in many cases they are "fit for purpose". As a general rule the accuracy can be defined as a multiple of the "ground sampling distance" or GSD. The GSD is the size of a pixel on the images captures. There are many variables which determine GSD but for a typical survey such as this I would usually aim for 2cm. The X/Y accuracy is usually accepted as 2 x GSD so 4cm and Z is 3 X GSD so 6cm. Therefore a DSM derived via photogrammetry is ideal for applications such as volumetric calculations.