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of "inexpensive" EDM has an accuracy about 0.04 feet at 1500 <br />feet. The price is usually reflected in the range <br />and beam width, not the accuracy. <br />LOCATING AND RELOCATING BENCHMARKS OR HEADSTAKES <br />One of the most immediate problems racing the field crew contem- <br />plating a return to a study area is their ability to relocate the bench- <br />mark and headstakes. If the study area is one of many, and/or heavily <br />vegetated, documentation of benchmarks and headstakes locations is a <br />great concern. It is amazing how quickly those things can disappear in <br />the-brush. Two fairly simple-methods can be used to accomplish this re- <br />location: the chord method or the bearing and range method. <br />Chord Method <br />The chord method utilizes a fixed distance from two or more easily <br />recognized landmarks to a benchmark or headstake. This method may be <br />used in conjunction with on-site photographs and the bearing and range <br />method. <br />Figure A-13 shows the concept of the chord method for locating a <br />benchmark. During the initial placement of the benchmark, the distance <br />to a well defined landmark, is. documented (description <br />of the landmark, including photographs, Figure A-13a). On subsequent <br />trips the landmarks are located, and an arc of the prescribed distance <br />made from each landmark (Figure A-13b). The intersection of the chord <br />traces marks the location of the benchmark. <br />rooole <br />BLAZE X10 FT <br />ONr/O,c BM 12 FT. _ 12 r T. <br />TREE ?- - - <br />???ARK ON BOULDER / - , - <br />\ SHAPED LIKE <br />? FOOTBALL HELMET <br />S F? <br />Figure A-13. Chord method of relocating a benchmark.