purpose of the map. The following guidelines suggest the nature of typical map specifications. A map should present legibly, clearly, and concisely a  summation  of  all  information  needed  for  the  use intended, such as planning, design, construction, or record. Topographic maps for preliminary site planning should preferably have a scale of 1 inch = 200 feet and a contour interval of 5 feet. These maps should show all topographic features and structures with particular attention given to boundary lines, highways, railroads, power lines, graveyards, large buildings or groups of buildings,  shorelines,  docking  facilities,  large  rock strata, marshlands, and wooded areas. Secondary roads, small isolated buildings, small streams, and similar minor features are generally of less importance. Topographic   maps   for   detailed   design   for construction  drawings  should  show  all  physical features,   both   natural   and   artificial,   including underground  structures.  Scales  commonly  used  are 1 inch= 20 feet, 1 inch= 40 feet, and 1 inch = 50 feet. The  customary  contour  interval  is  1  foot  or  2  feet, depending on the character and extent of the project and the nature of the terrain. Besides contour lines, show any spot  elevations  required  to  indicate  surface  relief. Additional  detail  features  that  are  usually  required include  the  following: 1.  Plane  coordinates  for  grid  systems,  grid  lines, and  identification  of  the  particular  system  or  systems. 2. Directional orientation, usually indicated by the north arrow. 3. Survey control with ties to the grid system, if there is one. This means that the principal instrument stations from which details were located should be indicated in a suitable manner. 4. All property, boundary, or right-of-way lines with  identification. 5. Roads and parking areas, including center-line location and elevation, curbs, gutters, and width and type of pavement. 6.  Airport  runways,  taxiways,  and  apron pavements,  including  center-line  locations  with  profile elevations  and  width  and  type  of  pavement. 7. Sidewalks and other walkways with widths and elevations. 8.   Railroads,   including   center-line   location, top-of-rail elevations, and any turnouts or crossovers. 9. Utilities and drainage facilities, such as gas, power, telephone, water, sanitary sewer and storm sewer lines,  including  locations  of  all  valve  boxes,  meter boxes, handholes, manholes, and the invert elevations of  sewers  and  appurtenances. 10.  Locations,  dimensions,  and  finished  floor (usually first floor) elevations of all structures. Q1. Q2. Q3. Q4. Q5. Q6. QUESTIONS Describe topographic control. Assume that you are establishing the primary vertical control for a topographic survey. The terrain is level and the desired contour interval is 1 foot. What is the maximum error closure? Can you use stadia leveling to achieve this error of  closure? You  are  detailing  a  point  from  a  primary  control station that has a known elevation of 174.3 feet. Your height instrument (h.i.) above the station is 5.6 feet. After reading a stadia interval of 2.45, you train the center hair of your telescope on the rod to match your h.i. and read a vertical angle of +6 °36t. If the stadia constant is 100 and the instrument   constant   is   1,   what   is   the   (A) horizontal distance, (B) difference in elevation and (C) elevation of the detail point? (Use the exact  stadia  formulas.) Your transit equipped with a stadia arc, is set up at point A (elevation  = 245.2 feet) and you are sighting on point B. Your h.i. is 4.3 feet. The line of sight is at 5.8 on the rod and the stadia reading is 6.43. The stadia arc has index marks of H = 0 and V= 50. The stadia arc readings are V = 63 and H = 12. Your stadia constant is 100 and the instrument  constant  is  O.  What  is  (A)  the horizontal  distance  to  point  B  and  (B)  the elevation of B? Define  contour  interval. On  a  topographic  map,  when  a  contour  line closes on itself, what is being portrayed? 8-24