CHECKING   COMPUTATIONS.—   Most mathematical  problems  can  be  solved  by  more than one method. To check a set of computations, you  should  use  a  method  that  differs  from  the original method, if possible. An inverse solution, starting with the computed value and solving for the field data, is one possibility. The planimeter and the protractor are also used for approximate checking. A graphical solution can be used, when feasible,  especially  if  it  takes  less  time  than  a mathematical or logarithmic solution. Each step that  cannot  be  checked  by  any  other  method  must be   recomputed;   and,   if   possible,   another   EA should recompute the problem. When an error or mistake   is   found,   the   computation   should   be rechecked  before  the  correction  is  accepted. Drafting Used In Surveying The  general  concept  of  drafting  and  the  use of drafting instruments were discussed in chapters 2 through 5. By this time, you should be familiar with the use of various drafting instruments and with the elements of mechanical drawing. Draft- ing used in surveying, except for some freehand sketches,  is  generally  performed  by  mechanical means;  for  example,  the  drawing  of  lines  and surveying symbols is generally done with the aid of  a  straightedge,  spline,  template,  and  so  on. The  drawings  you  make  that  are  directly related  to  surveying  will  consist  of  maps,  profiles, cross  sections,  mass  diagrams,  and,  to  some extent, other  graphical  calculations.  Their usefulness depends upon how accurately you plot the   points   and   lines   representing   the   field measurements.  It  is  important  that  you  adhere  to the requirements of standard drawing practices. Correctness,   neatness,   legibility, proportioned  drawing  arrangement professionalism. and  well- are signs of In drawing a PROPERTY map, for example, the  following  general  information  must  be included: 1.  The  length  of  each  line,  either  indicated on the line itself or in a tabulated form, with the distances  keyed  to  the  line  designation. 2.  The  bearing  of  each  line  or  the  angles between lines. 3.  The  location  of  the  mapped  area  as referenced  to  an  established  coordinate  system. 4. The location and kind of each established monument  indicating  distances  from  reference marks. 5.   The   name   of   each   road,   stream, landmark,  and  so  on. 6.  The  names  of  all  property  owners, including  those  whose  lots  are  adjacent  to  the mapped  area. 7.  The  direction  of  the  true  or  magnetic meridian,  or  both. 8.   A   graphical   scale   showing   the corresponding  numerical  equivalent. 9.  A  legend  to  the  symbols  shown  on  the map,  if  those  shown  are  not  standard  signs. 10. A title block that distinctly identifies the tract mapped or the owner’s name. (It is required to  contain  the  name  of  the  surveyor,  the  name of  the  draftsman,  and  the  date  of  the  survey.) Besides  the  above  information,  there  are  some other items that may be required if the map is to become  a  public  record.  When  this  is  the  case, consult  the  local  office  of  the  Bureau  of  Land Management  or  the  local  surveyors’  society  for the  correct  general  information  requirements  to be  included  in  the  map  to  be  drawn. In drawing maps that will be used as a basis for  studies,  such  as  those  to  be  used  in  roads, structures, or   waterfront   construction,   you are  required  to  include  the  following  general information: 1. Information that will graphically represent the features in the plan, such as streams, lakes, boundaries,   roads,   fences,   and   condition   and culture  of  the  land. 2.  The  relief  or  contour  of  the  land. 3.  The  graphical  scale. 4.  The  direction  of  the  meridian. 5. The legend to symbols used, if they are not conventional  signs. 6.  A  standard  title  block  with  a  neat  and appropriate title that states the kind or purpose of the map. Again, the surveyor’s name and that 11-9