Mapping software 2-3cm accuracy without GPC requirements

FlyaDrone · Oct 2, 2017

I have been looking at a rather powerful standalone application for 2D & 3D orthographic mapping applications. They are currently used throughout the USA and world as a go to solution for traffic scene reconstruction purposes. They are able to achieve 2-3cm accuracy without the need to pay for or deploy GPC designation. Also you own the software and can kick off a run of your data whenever you wish to.

https://www.iwitnessphoto.com/support/iWitnessPRO-Agilis-Released.pdf

Tuna · Oct 2, 2017

I suspect that by 'accuracy' they actually mean resolution. Without GCP's, they have no means to correct for drift across the scene.

FlyaDrone · Oct 2, 2017

I am not a mapping expert but if you look at their website the application is used for photogrammetry solutions in forensic investigations most often related to traffic accidents resulting in 1 or more deaths. The accuracy term would apply to actual measurements obtained from using their app. It calculates the measurements from one or more known distances that are taken in one or more of the photographic sequences. The software then applies algorithms to make applied measurements in relation to and from the known distances used as reference points. Accident reconstruction analysis requires measurements to develop accurate court room testimony from expert witnesses. Officers assigned to this type of accident investigation are all equipped with precise measurement tools.

I hope this addresses your comment and fully realize that I did not address the definition of "to correct for drift across the scene". Perhaps others will help us to better understand the capabilities of this application as it does address digital mapping uses.

Tuna · Oct 2, 2017

Hmmm... the thing is that if you take enough measurements, you're effectively recreating GCPs by triangulating points in the scene.

That's fine for relatively small and open areas, but over larger distances, the inaccuracy of distance measurement will take over. If I'm mapping a 12 acre site, I don't have 'one or two known distances' accurate to the 2cm they require to generate the map.

That's not to discount this solution, but there are limitations to the technique - and that's the reason you can get it for free, but pay thousands for a GCP system. For surveying smaller homes, it should do a great job.