updated: 26-Nov-2009

 Copan for Windows

Field Bearings Processing

Contents

Use this module to process combined compass, inclinometer and rangefinder data — azimuths (or bearings), vertical angles, slope distances, and instrument and signal heights — whether concerning many connected traverses, unconnected radial surveys, or combinations thereof, to calculate new points. Data can come from data logger files or be manually input. Traverses can be adjusted for misclosure and new points may be saved.

Note that ordinary total station data, intersections, resections, and redundant observations are not handled here. (For ordinary field data, use the § Field Data Processing module. For intersections, use the § COGO Calculations module. For resections, use the § Field Resections Processing module.) And this module is best for raw, field bearing traverses, not for reduced, map bearing traverses with distances already reduced to horizontal. (For such needs, use the § Map Traverses module or the § Map Checks module.)

Also note that, while there are certain similarities between the Map Traverse and the Field Data modules, there are various operational differences (other than the type of map/survey data involved). If you are familiar with one and new to the other, please study the appropriate manual and dialog carefully.

1. To Process Field Bearings

1. Calculation | Process Field Bearings...
2. Optionally Load... a field data File. (See § Field Files.)
3. Edit data in the big edit box as required. NB: To move the text cursor: Use the arrow, Tab, or Enter keys, or the mouse pointer. To manually insert a tab, copy and paste an existing one.
4. To enter setups and observations data, use the mini edit boxes and the relevant Insert button. To enter project, instrument and scales data (such as magnetic-grid north correction), use the supplementary dialog via the More data button.
5. Save the Field file for reuse.
6. Optionally change the precision of displayed/listed distances and coordinates via Settings....
7. Calculate (or OK) to process the field data, adjusting the traverses if appropriate (see § Traverse Processing).
8. To graphically view the shots: Close the Info Display window if it is open, and minimize or move aside — but do not close — the Field Data window.
9. Optionally List the field Data, the Calcs, or the Points that have been computed.
10. Optionally choose whether to Renumber new points or replace existing points (see § Point Renumbering or Replacement) and Save the Points that have been computed.

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2. Field Bearings Entry

Setups and Observations Data Entry

• For each instrument Setup insert only the following:
  • At #   the station point number,
  • Ht. Instr.   the instrument height — if elevations are required.
  They stay in effect until a new Setup is inserted. After a Setup line, multiple side-shots and one traverse leg can appear in any order.
• For each "shot" Observation, insert the following:
  • To #   the target point number,
  • Bearing   the bearing value (or a bearing expression),
  • Vert. Circle   the vertical circle value (or zenith distance),
  • Slope Dist.   the slope distance,
  • Ht. Signal   the signal (or pogo) height — if elevations are required,
  • Code   a point code, if needed,
  • Note   a point note, if needed.
• For a remote elevation measurement (REM), insert it as an Observation but without a Slope Distance (or possibly also without a Horizontal Circle). See Remote Elevation Measurement in § Field Files for details.
• For the last leg of each traverse, be sure to use one of these buttons:
  • end open for an open traverse (i.e., ending on an unknown point), or
  • end closed for a closed traverse (i.e., ending on a control point or on its initial setup point).
  If the last leg of a traverse has not been identified, Copan may not report results properly.

Project, Instrument and Scales Data Entry

• Insert any desired Project data, anywhere. Note however, that, along with Instr. ID, such data are ignored during calculations.
• Insert any Scales or Instrument constants, whenever they differ from their previous values. These are (along with their default values)
  • Projection SF (1.0) for map projection distortion — applies only to horizontal distances,
  • Units Factor (1.0) for height and distance unit conversion (e.g., feet to metres),
  • Dist. Factor (1.0) for slope distance multiplicative correction (e.g., due to extreme temperature),
  • Dist. Corr. (0.0) for slope distance additive correction (e.g., prism constant),
  • Azim. Corr. (0.0) for adding to azimuth (bearing) values (e.g., magnetic to grid),
  • VC Corr. (0.0) for adding to vertical circle values,
  and they stay in effect until new ones are inserted. Be sure to use the proper correction! In most cases, the default values are appropriate. A units factor of 3.2808399 is needed if measurements are in metres and coordinates are in feet.

3. Field Files

4. Field Bearings File Example

              AC= 5.24
at= 382                                            HI=  1.55
    to= 800   az= 235.42   VC= 90.18   SD=   4.6   HS=  1.58
    to= 801   az= 226.06   VC= 90.24   SD=  22.2   HS=  1.58
    to= 802   az= 219.54   VC= 90.48   SD=  25.6   HS=  1.58
    to= 804   az= 229.30   VC= 90.36   SD=  24.6   HS=  1.58
at= 804                                            HI=  1.55
    to= 805   az= 194.00   VC= 90.36   SD=  35.0   HS=  1.58
    to= 806   az= 134.18   VC= 90.06   SD=   7.8   HS=  1.58
    to= 807   az= 129.54   VC= 90.18   SD=  17.8   HS=  1.58
    to= 387   az= 133.00   VC= 89.36   SD=  31.0   HS=  1.58
    end= closed

4. Notes

• If you need to manually insert a tab, such as when you wish to add a code or remark to an observation line, copy and paste an existing tab — there will always be one between two auto-inserted attribute=value pairs.
• Currently, heights are carried forward, from the known setup to a target, not from a known reference to the setup. To do the latter, you need to trick Copan by manually converting the trigonometric height observation from a backward to a forward form (i.e., switch the HI and HS, and suplement the VC).
• Both negative and zero values for HI or HS are correctly interpreted.
• When a setup point's elevation value is missing (or null), Copan does not use any rises to targets (i.e., target elevations will be null).
• Also, a missing HI or HS yields a null rise and a null target elevation.

updated: 26-Nov-2009