of the draftsman, as well as the date of survey, are  to  be  included  in  the  title  block. Maps developed as a basis for studies are so varied  in  purpose  that  the  above  information  may be adequate for some but inadequate for others. The   Engineering   Aid,   when   in   doubt,   should consult the senior EA, the engineering officer, or the  operations  officer  as  to  the  information desired  in  the  proposed  map.  The  senior  EA  or the  chief  of  the  field  survey  party  is  required to  know  all  these  requirements  before  actual fieldwork is started. A map with too much information is as bad as a map with too little information on it. It is not surprising to find a map that is so crowded with information  and  other  details  that  it  is  hard  to comprehend. If this happens, draw the map to a larger scale or reduce the information or details on  it.  Then,  provide  separate  notes  or  descriptions for  other  information  that  will  not  fit  well  and thus will cause the appearance of overcrowding. Studying the features and quality of existing maps developed   by   NAVFACENGCOM   and   civilian architects  and  engineers  (A  &  E)  agencies  will  aid you  a  great  deal  in  your  own  map  drawing. Orientation Symbol Every map you draw has to have an ORIEN- TATION  SYMBOL  (sometimes  called  meridian arrows)  on  it.  The  symbol  that  represents the  direction  of  the  meridian  is  indicated  by a  needle  or  feathered  arrow  pointing  north.  It must  be  drawn  long  enough  that  it  could  be transferred  accurately  to  any  part  of  the  map. The  FULL-HEAD  ARROW  represents  the  true meridian;  the  HALF-HEAD  ARROW,  the  mag- netic  meridian.  If  both  are  drawn,  as  shown  in figure  11-1,  the  angle  between  them  must  be indicated.  The  general  tendency  is  to  draw  the symbol  in  an  artistic  way;  however,  the  simple design shown in figure 11-1 is adequate for most purposes.  If  possible,  the  top  of  a  map  must always be oriented north; however, the shape of the mapped area or the most important features of  the  project  may  alter  this  preference. Kinds of Maps Maps   are   classified   according   to   purpose, scale,  or  type.  Maps  classified  according  to purpose  include  strategic,  tactical,  and  artillery maps;  communications,  utilities,  or  soil  maps; and  maps  pertaining  to  special  studies.  When maps are classified according to scale, you have large-scale, medium-scale, and small-scale. Some Figure  11-1.-An  orientation  symbol  or  meridian  arrows. of  the  more  common  types,  such  as  geographic, planimetric,  topographic,  hydrographic,  special- purpose,  and  photomaps  or  mosaics,  are  briefly described in the next several paragraphs. GEOGRAPHIC MAPS.— A geographic map is a map of a large area, such as that of a state or  country,  that  shows  the  location  of  towns, counties,  cities,  rivers  or  streams,  lakes,  roads, and  principal  civil  boundaries,  such  as  county  and state lines. Maps showing the general location of the  works  of  people,  such  as  the  Railroad  Map of  the  United  States,  the  Irrigation  Map  of Arizona,  and  the  Panama  Canal  Zone  Map,  are classified  as  geographical  maps. PLANIMETRIC MAPS.— These maps show natural  or  man-made  features  in  a  horizontal plane  only.  Relief  in  a  measurable  form  is omitted.  A  few  examples  of  planimetric  maps are  property,  maps  for  city  layout,  site  plan, communications,  route  and  distance,  and  isogonic maps  of  the  magnetic  variation  lines. TOPOGRAPHIC  MAPS.—  Maps  that  depict the  natural  and  man-made  features  of  the  earth’s surface   in   a   measurable   form,   showing   both horizontal   and   vertical   positions   are   called topographical maps. Vertical positions, or relief, are normally represented by contours. A precise topographic   map   shows   surface   features   so perfectly that it can be used for making an exact three-dimensional  model  of  the  area.  Such  a model  is  called  a  RELIEF  MAP.  Your  work  in 11-10