On Feb 23, 2017, at 08:06 PM, Bruce Mutton via Therion <therion@speleo.sk> wrote: Martin The Therion debug feature is useful, but I would suggest that it is for micro interrogation of at most a few scraps at a time, and not for quickly identifying the macro loop error health of a project. Typos like the one you describe would not be evident from scrap distortions, at least in my case, as (in the old days of manual surveying with compass and book) the scraps would be drawn using the erroneous data, so no distortion mismatch between centreline and scrap would be flagged by Therion. Would only be found by the person drawing noticing that something looked out of proportion. It is the question of your workflow. I check each scrap individually, I check each map, each bigger map etc. I check it after each equate command (new loop closure), etc. I'm not sure if the best way is to start from huge system down to individual scraps. Martin