I recently uploaded a sequence to Mapillary, but the GPS signal from my GoPro Max was very subpar. This was probably due to a lot of tall buildings disturbing the GPS-signal. After the images was processed I noticed that the images are located correctly relative to each other when enabling 3D mode, but they are incorrectly placed on the map. Navigating by the arrows therefor works poorly, but clicking on the next 3D sphere works great. Does Mapillary correct the green dots on the map after some further processing?
Yes, Mapillary will attempt to do some correction of GPS signal noise using OpenSfM (https://opensfm.org/) - Structure from Motion. However we donât yet display these corrected green dots on the map - that is something we would like to do in the future.
Yes, I overall understand the process. You determined relative orientation between two images that have common features and, then, you do a global optimisation combining relative orientations and absolute (although approximative) positions from GPS.
Still, what are the yellow/orange dots?
I see a very bad case, where image view overlapping is also poor:
I can understand trying to calculate the âcorrect locationâ for some internal processing. But itâs wrong for almost all the locations Iâve checked in the past month. If you want to show that indicator before itâs accurate while you develop the algorithms, thatâs fine I guess. But the actual indicator is now gone - I have no idea which point I have selected, because the estimated point is almost never there. This has turned from an experimental feature into a usability issue. The first time I saw it I was convinced it was some sort of rendering bug offsetting the indicator.
@HellPhoto - Agreed that we have work to do here - though I donât believe this functionality has changed recently? The original position is visible before you click on a point, and the computed one is shown after you click on a point.
Yes, this has been an issue for a while. Once I move the mouse cursor away from the point that is clicked - it is no longer visible. Only the orange one remains. It only shows up if you mouseover sequence navigation buttons (and those are technically next/previous points):
Please do not ruthlessly âimproveâ the location of for example Mapillary : viewed against the background of either OpenStreetMap, or -logged-in at OSM- against the Digitaal Vlaanderen GRB (= official couple of centimeter or so accuracy map) the GoPro Hero9âs position is - in a difficult location, given tall buildings on two sides - much better than Mapillaryâs âcomputedâ then fiddled -but actually fumbled- location;
just looking at the picture youâd see it was taken somewhere in line with the underpass (which is clearly shown on the GRB layer in OSM), whereas the âcorrectedâ position places it - my guess, as a scale stick is missing on Mapillary - some 20m to the left, as if I were cycling straight at the middle of that apartment block - quod non.
= = = another example :
Looking at Mapillary youâll see it was taken at the âjumpâ in the building line, GoPro shows it perhaps 2m ahead of where I was, and perhaps 1 - 1½m to the right; Mapillary has correctly corrected that forward bias, but placed me in the raised planter, which you can see wasnât the case, thus shows a worse sideways accuracy.
So by all means keep trying, but for now youâd likely benefit from betting on both some 3D-model builder and actually analysing the photo for clues.
Spotted other examples, where a photo taken on a path was âcorrectedâ to be way beside the path; think correcting in urban surroundings will be of most benefit?
Absolutely, we will always make the ârawâ location available, so that should be something users can always consult. As you mentioned there are lots of issues with the current âcomputedâ location - which is precisely what we either need to fix (or perhaps stop showing in cases where we know its unreliable).
You can see in the following sequence recorded on a motorway in open field area with RTK GNSS that âcomputed positionâ is just stuck at a point for more than 20 pictures. Later, you can see it jumping left or right from the track.
