> ...it sounds like you're establishing the distance between the marks on your baseline using the newly calibrated EDM. I was referring to establishing the distance by use of a steel tape...
I do understand. You could use a tape if you wish.
Tape the whole slope length fully supported on the grass and correct to horizontal. Level between the endpoints to accurately determine the slope. If the slope is consistent you'll be fine.
I used an EDM. Actually, I used 3 EDMs.
Earlier I suggested that you get several instruments to measure your baseline. If you don't have easy access to several instruments of your own perhaps you could interest some other surveyors in your area to bring theirs. Maybe your friendly neighborhood instrument salesman would contribute a loaner as a public service.
Once you have tripods with tribrachs set up over the points its amazing how fast you can repeat the measure with several instruments.
Some good information here. Some years back I sought out a base line at one of our local airports to do something similar with our EDM. Measuring against a steel tape over a relatively short distnace didn't really occur to me as I know the ppm of the EDM combined with the prism offset were not going to be as precise on a short baseline as a properly tensioned and corrected steel tape. The baseline I found to be in such a sad state of disrepair, I quickly lost all enthusiasm for using it. This is when I realized that I'm constantly checking my EDM against my Trimble GPS gear measurements when I use it to establish control points to be used conventionally. I routinely compare the two measured distances. I believe with the acceptance of GPS as a reliable surveying tool, the need for fine tuned base lines has somewhat diminished.
Carry on.
Just because I'm paranoid, doesn't mean they aren't out to get me.
Difference between prisms.
I have observed a difference of up to 0.021' difference between prisms. (I got an oddball one) most of mine are within 0.011'.
I forgot to mention, shoot the prism at 10' away, and measure it with the box tape.
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