Problems arising in using UAV ( drones ) for photogrammetric mapping.
Interestingly, more and more photogrammetry operations are acknowledging how difficult it is to obtain consistently accurate results for drone based mapping projects.
Over the last 7 years of doing aerial mapping using UAV’s ( drones ) and photogrammetric software such as Pix4d, Agisoft and opensource solutions – if the input data is not perfect the chances of processing errors’ occurring dramatically increase.
For us the 4 lessons learnt are :
The value of well positioned and well-marked Ground control points spaced no more than 300m apart.
Ground control must be placed around perimeter and in centre of project – minimum of 5 points is critical.
Enough ground truthing points should be measured across site to have reliable quality control process post data processing.
Flying the site is the simplest of the tasks involved in aerial mapping
This month in Point of Beginning magazine there is an article supporting how complex photogrammetry really is : to quote “ As more land surveyors use drones as part of their daily work, they are finding themselves having to learn the ropes of photogrammetry. Having done data processing for thousands of drone survey projects, we have learned the hard way why photogrammetry is a PhD-level science. We have banged our heads against every wall there is and learned some essential lessons that we now apply to every project we work on. We have explored which parts of the photogrammetry process can be automated and tested the fully-automated tools on the market.
In order to make sure our team has the chops they need, we rely on the American Society of Photogrammetry and Remote Sensing (ASPRS) as the only nationwide organization that provides certification for photogrammetry. Issues are common in drone photogrammetry projects — nearly half of the projects we process for customers have some sort of issue. We’ve found that having a qualified photogrammetrist involved in every drone survey is necessary to answer three critical and common questions:” read more at