Looks very good Mark. I notice that you did not include the Bell footage though. You have Bell as standing on a concrete plinth as number 59. Is that where he was standing when he took his footage of the motorcade on Houston street?
Also, as a side note, how confident are you that you have the correct position of Altgens when he took the "Altgens 5" photo while standing at the Main/Houston street intersection? (i'm not questioning your positioning of him, just curious as to how accurate you think you were able to get him. To within 3 or 4 feet do you think?)
Thanks Margaret. The early part of the Bell film looks somewhat strange as it was framed rather high, so I didn't use the early part of it as the Limo travelled along Houston Street (only on the turn onto Elm). I think he was standing on the concrete plinth, as the angles seem to match up relative him looking down the pathway to the TSBD:
Someone helpfully constructed a montage image which shows his position:
The original source of this Bell in this image is the Skaggs photo here:
Yes, I would say that Altgens was within a few feet of where I have him on the map. With this kind of triangulation the accuracy can never be perfect, but anywhere inside the dark circles should be about right. The more photos from different angles that I use the more accurate it will be, which is why I am especially confident about the Limo on Elm Street. We have 4 films, and several photos tracking the car at different points and from different angles in the crucial 15 seconds of the sequence.
In his early "3" photo you can judge the Altgens horizontal position relative to the road markings on Main Street. Due to perspective, the white lines converge to a vanishing point so we can judge his position reasonably accurately:
For the "Altgens 5" photo that you mention I have assumed he is in the same position because the crowd on the corner was relatively dense as seen from the Bronson photo:
A good reference point I used for triangulating is the "No Parking" sign in front of the ramp entrance:
I also used this to position Orville Nix in a similar position as you can see that sign in his film too: