Figure 8-10.-Notes for locating topographical details by transit and stadia.Now let us see how all that you have learned abouttransit-stadia topography is used in the field Figure 8-10shows field notes for locating topographic details bytransit and stadia. The details shown by numbers in thesketch on the Remarks side are listed on the data side bynumbers in the column headed Obj. At the top of thepage on the data side, you see that control point D1 wasused as the instrument station. Immediately below this,you see that from instrument-station D1, the transit wasbacksighted to point A and that all horizontal angleswere measured to the right from the backsight on A.In the third line from the top on the data side, yousee that the known elevation of D1 is 532.4 feet and thatthe vertical distance (hi.) from the point or marker at D1to the center of the instrument above D1 is 4.8 feet. Thisvertical distance was carefully determined bymeasurement with a tape or rod held next to theinstrument.Now let us see how each of the objective points wasdetailed. We will begin with point 1. Remember that inthis example, D1 is the instrument station from which allobservations are made.To determine the direction of point 1, train thetransit telescope on A and match the zeros. Next turn thetelescope right to train on point 1 and read the horizontalangle (30010’).8-10
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