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No.50 - January 2002 | Contex HOME CoLAS Survey Weekend Can you set out a baseline? Could you transfer a level to a TBM? Have you ever used an optical square or dumpy level? If the answer to these questions is no then I have only one more question for you - How did you spend the last Bank Holiday weekend? One hardy group of CoLAS members braved the elements to gain some hands-on experience of surveying. Being a Bank Holiday, we anticipated rain, sleet, snow, hail, and hurricane force winds. In fact we had a very pleasant weekend with warm sunshine (talk about climate change!). I planned to cover setting out baselines, survey grids and the like on the Saturday, levelling on the Sunday, with a chance for the students to put what they had learned into practice on Monday. All within the usual narrow tidal windows. Quite a challenge? Perhaps, but as usual CoLAS members proved equal to it. The team installed the permanent baseline on the foreshore by the Prospect of Whitby in quick time, handling ranging poles with remarkable confidence after just a few minutes practice. The complexities of the optical square proved no match for CoLAS members, and when it came to setting out right angles using a tape and 3-4-5 triangles anybody would have thought they were post-graduate geometry students. The only problem on the day was damaged threads on the survey marks which prevented us from attaching the high-visibility caps. We decided to defer this problem to Sunday and headed for a well earned de-brief at the Prospect. Sunday was levelling at Custom House in the City. Transferring a level to an urban site is seldom easy - especially if you are unfamiliar with dumpy levels. The CoLAS team was undaunted. Initially, some of the team had problems reading the staff (which is difficult for everyone new to surveying), but this was quickly overcome. The results were little short of incredible. The closed transit covered a distance of just under 300 metres and a vertical change of over 13m. The total error was just 11mm! Personally I would like to claim that this was the result of expert tuition by a gifted (not to mention rugged and handsome) instructor. Sadly for my ego the truth is simply that the result reflects the aptitude and efforts of the CoLAS team. Monday saw us back at the Prospect of Whitby. The team was ready to put what they had learned into practice. Disaster struck right at the start of the day. A leg broke on the tripod! In the best British tradition we improvised and overcame, proving that all you need is string, gaffer tape, and perhaps blu-tack. Oh, and a set of taps and dies… Remember those troublesome survey markers on Saturday? A few minutes with the taps - the thread was good as new - and the high-visibility caps were attached. The CoLAS team watched, initially with scepticism, then with interest, then they helped with enthusiasm. Rose was heard to say "… and where did you say we can buy taps and dies…?". I think the team were put off their stride by the problems with the equipment on Monday. Checking the day’s results showed a large error - probably the result of a staff which wasn’t fully extended. It can happen to the best of us. It had been a hard day and we retired to the Prospect. The team was obviously feeling a little frustrated and dejected about the result - but they weren’t going to be beaten. The decision to re-do the transit on the next foreshore-friendly weekend was unanimous. The students had clearly enjoyed the weekend, and their enthusiasm made the course a pleasure for the instructor. Thanks to all of you. Iain McCulloch |
