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Topic: When Geotagging Synths, Should We Mark Center or Beginning?

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NateLawrence (11 months ago)
Photosynth team, when we geotag our synths, do you have a preference as to where the pushpin is placed?

Would the center of a Spin or Walk or Wall or Panorama synth be what you're looking for or would you prefer that we mark the beginning of a Spin, Walk, or Wall synth?

Do you plan to bring back geo-aligning (I imagine so) and might you automatically adjust where the pushpin is located, once you know where all the cameras in the synth are?
So far I have placed pushpins in the center.

However, I feel synth representation on the map should be improved. I envision...
- Panorama as a dot.
- Spin as a circle, oval or spiral.
- Wall and Walk as (bended) lines.

Even better, have them represented by a camera icon or a path of them.

With smartphone sensors the spot where each frame has been taken can be deduced. At least relative to each other. Position on the map can be fine tuned manually, but needs good map and/or satellite imagery which is on proper geo co-ordinates of the map globe.
Synthing only a few pics, 3 to 5, I find the creation dialogue automatically puts the pushpin in the middle of the wall.
wideangle (11 months ago)
The default behaviour if you upload geotagged photos is to tag the synth with the GPS coordinates of the first tagged photo in the set.  This may change in the future.

Anne (Photosynth team)
NateLawrence (11 months ago)
Anne, thanks for the insight.


Joscelin, yep, my traditional practice has been to tag the center of my camera positions.
I'd still like to get back to having geo-aligning available.

The overhead map of the camera positions that we can pull up in the Photosynth 2 viewer gets pretty close to something useful to align to the map, given rotation and scaling controls like the Photosynth 1 editor has, although combining the camera positions with the point cloud would be my preference for alignment.
I am not sure if I have ever properly understood the alignment feature in Ps1.
@Anne. Are you sure? In the upload page, photos show in reversed order. It seems to me that geo tags are used of the photo first in the list, which is last in the upload and which I would call last in the set, especially when taking chronological order on date/time taken into account.
NateLawrence (11 months ago)
Joscelin, with regards to the image order on the upload page, David explained the team's thoughts here:

I would say that certainly Photosynth is aware of the timestamp on the photos, else it wouldn't start walk synths at the beginning, as it does, so if Anne says that in synths with geotagged photos the position of the first photo is used for the synth, why should we question that?

I'm not trying to be confrontational. I'm just curious what makes you think so.
Do you have a walk synth where the first and last photos are far enough apart on the map to be noticeable where the pushpin on the map is definitely the last photo taken's position?


Separately, what were you asking about geo-alignment in Photosynth 1?
Did you mean you didn't understand how to use the interface or you didn't understand what the purpose was?
I have not been focus testing geo positioning, but the above is the result from the impressions I have with recent synths.
About geo-alignment in Ps1. I mean that I may not have completely understood both its purpose and interface. Directional orientation is clear, but is there something in sizing, as you, Nate, are referring to scaling. I can imagine scaling to match point cloud with the map, but I do not think my synths have ever been good enough in this respect.
NateLawrence (11 months ago)
Yeah, when the point cloud of the subject was clear, you just line up the corners of buildings or paths with the satellite imagery on Bing Maps by:
1) zooming to the appropriate level on the map, 
2) rotating the alignment ring via clicking + dragging the edge of the ring, and 
3) changing the size of the point cloud to match the map by 
a) clicking + dragging the alignment ring's resize handle (the left + right arrowicon) on the right hand edge of the ring) 
b) using the -|+ icons underneath the resize handle to change point cloud magnification within the alignment ring.

In terms of purpose, (assuming that Photosynth's reconstruction was accurate) it was a way of geotagging all photos in the synth's primary cluster at once, since Photosynth knows their relative positions.

Not only did this give each photo a lat/long in Earth coordinates, but all the fine grain detail of compass bearing + camera pose that Photosynth provides.

That was never quite capitalized on.
NateLawrence (11 months ago)
I'm still intent on seeing Photosynth camera positions in the context of a 3D Bing Maps control, but unfortunately when Photosynth was launching this stuff back in 2009, Bing Maps was busy rebuilding everything in Silverlight (which lacked the ability to use graphics cards for 3D) so just as Photosynth was mapping synth coordinates into Earth coordinates in a very detailed way, Bing Maps moved away from the Direct3D-powered (and thus Windows-only) Virtual Earth 3D to a 2D-only Deep Zoom Bing Maps control (which worked on both Windows and Mac, but not on mobile).

Today with Bing Maps moving back to a 3D map control again, this time powered by web standards 3D graphics tech which works on Windows, Mac, Linux, game consoles, tablets, phones, etc. and in all modern web browsers and Photosynth also using WebGL, hopefully we'll not see another setback like we did when Silverlight development was abandoned just as it added support to use the GPU in SL5 in December 2011.
Hi Nate, I suspected something like this. Has there ever been some sort of official explanation on this? I have not come across it. Anyway, I have used the alignment ring for orientation. I think proper Photosynth reconstruction was an issue next to my understanding. From what you explain, I now understand the power of the alignment feature.
Nate, you talk about camera positions on Bing Maps. As I have said above, I definitely agree that a pushpin representation is absolutely inadequate, not just for the Photosynth creator, but also for the audience.
@Anne and Nate. About the default placement of the pushpin. Taking as normal that 'first in the set' is first in the path, i.e. first in chronological order, then I can now confirm that auto pushpin placement is at last in the set (which is first in the upload list). I do not feel that this default is desired behaviour. This adds to the things that make me wonder if the programmers understand on what kind of product they are working and if the team is eating its own dog food, which I heard Balmer ones say is an adagio within Microsoft.
wideangle (11 months ago)
Looks like you found a new bug Joscelin.  The design called for using the GPS coordinates of the first image in the set.

Anne (Photosynth team)
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