Saturday, March 17, 2007

Comment on "Calculating Dimensions from Historic Photographs, etc." at histarch

I was once involved in the "opposite" idea, measured CAD drawings from current photos, using what was called then the Rolleimetric MR2 program. As it was a system of software and hardware, fairly expensive back in the early 1990s and the transition to visual computing was starting, I looked around. I can't recall the name of the software, I think at the University of Montreal, it used a known or estimated distance in a photo, i.e. a window well, and used that digitized distance to make a drawing from digitized (mouse pointed out) places on the photo, photos just beginning to be a part of Windows. It was in development, as was the AutoCAD interface with Rollei, which didn't "pan out" commercially as universality came into demand in drawing interchange formats (dxf), the close-range photogrammetric data can be used inside many CAD programs. I just read Adobe now reads AutoCAD dwg files and creates very good pdf (portable document) files complete with layers, a naming standard of which has been proposed for archaeology so attributes would be on standard named layers for archiving.

The Fourmilab in Switzerland, run by the co-author of AutoCAD John Walker has a weekly match-up of old photos from post cards etc., with modern photos online, overlaid in the window to make comparisons. He might be a source of information, AutoCAD has built in "cameras" etc., in double precision needed for accurate 3D mathematical depiction and has expanded into rendering, mapping, etc.

Ed.- I forgot to mention that the company representing the Rolleimetric MR2 system, working with them in Germany and with Schneider Instruments in New York, on Long Island, was/is the Canadian company, Prometric Technologies with Andrew Lane and Ray Masagin (apologies if the spellings wrong). They have worked on as-built landmark recording in Canada, and other projects (petroglyph recording photogrammetrically) as well as assisting Grossman & Associates, Inc. on the West Point Foundry deposits in Cold Spring, NY. 3/19/07

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