Good evening everyone,

I'm a geophysicist who needs to carry out topographic surveys from time to time. I have a Topcon Imaging Total Station - an IS303 - and with I have carried out successful surveys and scans - but only ever from a single known location.

Now I have a serious and urgent problem and I would be grateful if anyone can help me.

I carried out a survey of a mosaic which forms part of the floor of a cathedral. The mosaic is within a complicated room with immobile structures in the middle. It was necessary to scan from five locations within the room in order to cover the whole floor. At each scan location I recorded the position of the IS303 by resection from a set of points marked on the walls - a fairly normal procedure.

But now I can't get the Topcon software - Image Master - to assemble the separate scans. What it seems to need, and what I didn't record, was a set of backsights, one for each scan location, to a specific reference point. I have no idea why the system would need such a backsight. After all, resection to a set of points is much more secure than a single backsight. I have tried recalculating what angles and distances a backsight would give and editing the IS files accordingly. That only solves part of the problem and, boy, is this a cumbersome approach.

So does anyone out there have experience using the IS303 and Image Master software, combining multiple scans into a single model (with photographs taken by the IS itself)?

This seems to me to be such a routine requirement that I have to believe that someone out there can help. This is exactly the kind of thing which the IS303 was designed to do. Yet Topcon UK seem to be unable to help because they regard this as too old-fashined technology and don't even have the hardware and software themselves.

Kind regards,

David Jordan