Look, nobody is changing the subject. If you would just get busy and do it, we could discuss it. When interrupted by stellar posts like Bobw's, how can we not get distracted? It's your team that's putting up smoke screens Telf, not ours. Some folks just don't know how to focus like you and I. Please lead by example.<br /><br />You have the data, you know the geometry model. Use the Mosaic at keith's site for all I care. At some point, you have to put your pencil in your hand and work. Your above image seems to be a start.... keep going.<br /><br />FYI.... Naj was the one who was whining about me posting the color/ir image. Then you said "NO". We'll use MY pic. Whatever.....I was just trying to help.<br /><br />I would like to state for the record that you will probably get better results using the color/ir image. There's more definition and clarity of the geometry. For your experiment, that is the better image, but like I said.... I really don't care. If you're serious, and I hope you are, your results ought to be satisfactory. If not, I hope you give the color/ir a try and see what happens..... Understand my reasoning? No tricks, no quick dismissals, just honest, rigorous science.<br /><br />Also, I did find the margin of error refrence in Monuments.... It's +/- 3 degrees in either direction. So 33 could measure 30 or 36. Ok? I would expect your experiment to be even more off. If you used the color/ir I would say double it. With your image, I would say more. How much more? I dunno, what do you think?<br /><br /><br />In all seriousness....best wishes Telf, for a safe procedure tomorrow. Really <img src="/images/icons/smile.gif" />