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graphite  be  used  to  lubricate  transit  moving  parts when  the  transit  is  to  be  used  in  sub-zero temperatures   instead   of   the   light   film   of   oil (preferably watch oil) when its use is confined to an  area  with  normal  weather  conditions.  The lubricant  should  be  applied  thinly  to  avoid making  the  lubricated  parts  an  easy  repository  for dust  or  catcher  of  dust. Consult  the  manufacturer’s  manual  or  your senior  EA  whenever  you  are  in  doubt  before doing  anything  to  an  instrument. NOTE:   Information   on   tests,   adjustments, and minor repairs of surveying instruments will be presented at the EA2 level. TRAVERSE  OPERATIONS (FIELD  PROCEDURES) A  survey  traverse  is  a  sequence  of  lengths  and directions  of  lines  between  points  on  the  earth, obtained  by  or  from  field  measurements  and  used in determining positions of the points. A survey traverse may determine the relative positions of the points that it connects in series; and, if tied to   control   stations   based   on   some   coordinate system,  the  positions  may  be  referred  to  that system. From these computed relative positions, additional  data  can  be  measured  for  layout  of  new features,  such  as  buildings  and  roads. Traverse operations (actions commonly called TRAVERSING)  are  conducted  for  basic  area control;   mapping;   large   construction   projects, such  as  military  installation  or  air  bases;  road, railroad,   and   pipeline   alignment;   control   of hydrographic  surveys;  and  for  many  other projects.  In  general,  a  traverse  is  always  classified as  either  a  CLOSED  TRAVERSE  or  an  OPEN TRAVERSE. A  closed  loop  traverse  (fig.  13-29,  view  A), as  the  name  implies,  forms  a  continuous  loop, enclosing  an  area.  This  type  of  closed  traverse starts and ends at the same point, whose relative horizontal position is known. A closed connecting traverse  (fig.  13-29,  view  B)  starts  and  ends  at separate points, whose relative positions have been determined by a survey of an equal or higher order accuracy.  An  open  traverse  (fig.  13-29,  view  C) ends  at  a  station  whose  relative  position  is  not previously known, and unlike a closed traverse, provides  no  check  against  mistakes  and  large errors.    Open   traverses   are   often   used   for preliminary  survey  for  a  road  or  railroad. Figure 13-29.-Types of traverses. The  order  of  ACCURACY  for  any  traverse is determined by the equipment and methods used in  the  traverse  measurements,  by  the  accuracy attained, and by the accuracy of the starting and terminating  stations.  Hence,  the  order  of  accuracy must  be  specified  before  the  measurements  are started.  For  engineering  and  mapping  projects, the  distance  measurement  accuracy  for  both electronic  and  taped  traverses  for  first,  second, and  third  order  are  1/35,000,  1/15,000,  and 1/7,500,   respectively. For military use such as field artillery, lower order  accuracies  of  fourth,  fifth,  and  sixth  are 1/3,000,   1/1,000,   and   1/500,   respectively.   The order referred to as lower order is applied to all traverses  of  less  than  third  order. To   accomplish   a   successful   operation,   the traverse   party   chief   must   ensure   that   initial preparations  and  careful  planning  are  done  before the actual traversing begins. In the remainder of this  chapter,  we  will  discuss  some  of  the  basic procedures  normally  undertaken  by  a  transit-tape traverse party. ORGANIZING  THE  PARTY A traverse party may vary from 2 to about 12 personnel, all under the supervision of a traverse 13-27

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