The second segment of the range line location survey was a level 

 line survey beginning at the most seaward pipe on South Range north along 

 the beach to North Range. Figure A-3 shows the plan of the second seg- 

 ment of the range line survey with the transit stations, rod stations, 

 and measured lines as listed in Table A-2. 



This survey segment resulted in the location of four additional 

 points as shown in Figure A-3. These points are: 



a. Two 1/2-inch-diameter stainless steel pipes approximately 

 45 feet apart at the mouth of Indian Canyon on Indian 

 Canyon Range; and 



b. Two 1/2-inch-diameter stainless steel pipes approximately 

 30 feet apart on North Range. 



These additional established points define the location of Indian Canyon 

 Range and North Range . 



A specialized surveying technique was used to determine the distance 

 between points located at the top and bottom of the sea cliff on South 

 Range. This involved setting up the survey as a trigonometric problem 

 in which the vertical angle and the distance between points at the top 

 and bottom of the cliff are measured in order to define a triangle as 

 shown in Figure A-4. A trigonometric solution of the right triangle pro- 

 vides the difference in elevation between the point at the top of the 

 cliff and the point at the bottom of the cliff. In order to determine 

 the difference in elevation between the two points to the nearest 0.01 

 foot, an exact measurement of the line-of -sight distance between the 

 points at the top and bottom of the cliff had to be made. This was accom- 

 plished by using a Hewlett-Packard 3800A Distance Meter. Exact measure- 

 ment of line-of -sight distance to the nearest 0.001 foot for distance up 

 to 3,000 feet is possible with this instrument. Two independent measure- 

 ments of the distance between points at the cliff top and bottom resulted 

 in measurements of 505.182 and 505.185 feet respectively. Thus, a slope 

 distance of 505.18 feet was used for the calculation of the difference 

 in elevation. The vertical angle of slope for the measurements was deter- 

 mined to be 35°56' by a transit. Trigonometric solution of the right 

 triangle and consideration of the instrument offsets results in a dif- 

 ference in elevation of 291.10 feet between the pipe bench mark at the 

 cliff top and the SI0 I bench mark on the beach (see Figure A-4) . This 

 determination of the elevation of SI0 I bench mark provided the necessary 

 link between the two segments of the range line location survey and 

 established the exact elevation of the SI0 II and SI0 III bench marks 

 on the beach. 



RANGE LINE BENCH MARK DESCRIPTION 



Each range line is located by two permanent bench marks. These 

 bench marks are 1/2-inch-diameter stainless steel pipes 56 inches long 



39 



