updated: 24-Mar-2011

 Copan for Windows

Map Traverses

  1. Adjust Bearing-Distance Traverses
  2. Map Traverse Data for Adjustment
  3. Map Traverse Files
  4. MT File Examples
  1. Curve Adjustments
  2. Export
  3. Reverse
  4. Notes

Azimuths (or bearings) combined with horizontal distances — pairs of values that are often known as calls, courses, or metes — are common on many cadastral maps and plans/plats. Copan refers to sequences of such reduced land survey data as map traverse data.

Use this module to compute and adjust for misclosure any number of map traverses and save the new points, whether or not the traverses are open, closed or adjusted. Use it to traverse around lot (or parcel) boundaries, including ones with curves, and to calculate the lot/parcel areas.

Note that if you are just checking the bearing and distance data from a map or deed, and not using a coordfile, you should use the § Map Check module. Also, this module cannot be used for raw field data, involving horizontal or vertical circle readings and slope distances. For such needs, use the § Field Data Processing module or its Field Bearings variation. Finally, 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 Adjust Bearing-Distance Traverses

From the Calculation menu, choose Adjust Brng-Dist Traverse (Map Trav).

  1. Calculate | Adjust Brng-Dist Traverse (Map Trav)...
  2. Optionally Load... a traverse Data file (see Map Traverse Files below).
  3. Optionally enter conversions: an Azimuth Correction, to be added to every bearing; a Units Factor, for converting distance units to coordinate units; a Scale Factor, for combined map projection and sea-level (or elevation) factor conversion.
  4. Enter or edit the bearing-distance traverse data in the big edit box. See below for a description of map traverse data for adjustment.
    To move the text cursor within the box, use the Arrow, Tab, or Enter keys, or the mouse pointer. Do not use the Space key to separate fields. To delete a chunk of text, select it with the mouse then click Cut (or type Ctrl-X) but be careful not to delete the embedded tabs within a line. To manually insert a tab, Copy and Paste an existing one. The Ctrl-Insert and Ctrl-Delete key combinations act like the Ins and Del buttons, that is, they insert and delete a line of data. To add a Point number automatically to the next blank line, press Enter when in the Distance column of the previous line.
  5. Optionally List the map traverse Data.
  6. Optionally Export.. in ESRI format or Reverse the direction of the map traverse Data.
  7. Optionally check the Auto insert proper AC box to have an azimuth correction automatically inserted at the start of the traverse such that a recalculation of the traverse would have no overall azimuth error.
  8. Save the Data for reuse.
  9. Calculate (or OK) the traverses, adjusting each one as desired (see § Traverse Processing).
  10. To graphically view the traverses: Close or hide the Info Display window if it is open, and minimize or move aside — but do not close — the Map Traverse window.
  11. Optionally choose whether to Renumber new points or replace existing points (see § Point Renumbering or Replacement) and Save the Points that have been computed.
  12. Optionally List the Points that have been computed.

To process map survey data: enter bearings and distances in the big box, and click Calculate.click for larger view

2. Map Traverse Data for Adjustment

3. Map Traverse Files

A map traverse file, as it is plain text (or Ascii), can have any name, though names with the .mt extension is advisable. You can edit it outside of Copan, but be sure to maintain proper formatting:

4. MT File Examples

Here are two map traverse files ready to be Loaded for calculation and adjustment.
Example 1:   Two simple traverses.
This file has a primary traverse and a secondary traverse. Three of the second traverse's legs are in a straight line.
Map Traverses
1st dummy line
2nd dummy line
3rd dummy line
9009                           primary
1463     235.2547     061.29
1462     255.1305     215.44
1461     232.3944     028.45
1460     182.1748     161.24
1464     272.0355     125.98
9008     217.3139     087.16
1461                           secondary
1465     092.2112     160.40
1466     182.0352     160.93
1467     "            040.72
1468     "            007.60
1469     183.4005     059.19
1470     260.5657     160.73
1471     000.0812     061.41
1460     002.1748     077.60
Example 2:   A traverse with curves.
This traverse has a series of compound curve radials (see § Traversing Curves on how to define curves along a map traverse).
Map Traverses
C:\Documents and Settings\martinf\My Documents\Whistler\13031.mt
5819     089.1140     166.64
5820     s11.5550w     34.06
5821     "            108.57               bc
5827     s78.0410e   3105.89               cc
5823     n79.1910w     "                   poc
5822     s79.1910e   2342.01               cc
5824     n89.4134w     "                   poc
5822     s89.4134e     "                   cc
5825     s89.1943w     "                   poc
5822     n89.1943e     "                   cc
5826     s86.3512w     "                   ec
5787     w           103.24
5788     s08.02w      46.4

5. Curve Adjustments

If a traverse that contains curves is adjusted, its curves are affected as follows:

6. Export

Use the Export... button to export the current map traverses (starting from where you specify), in ESRI Traverse File format.

You specify the location and file name (the default being the current folder and current map traverse file, without the .mt) and Copan will save to file-name\file-name.txt (that's the funny way ArcGIS expects it).

Copan uses the latest saved coordinates for the start and end of each traverse, whether or not the traverse was adjusted. Also, it outputs traverse data in their combined interpreted and converted form (i.e., after expressions are evaluated and conversions are applied), but not in their adjusted form (i.e., before any traverse adjustments).

7. Reverse

Occasionally, you'd like to use an already entered traverse but in the reverse direction. Use the Reverse button to reverse the current map traverses (from last to first), each one in reverse point order.

Note that reversed traverse data are shown in their combined interpreted and converted form (i.e., after expressions are evaluated and conversions are applied). So if you want only the raw (or unconverted) data reversed, you must first temporarily remove the conversions.

8. Notes

updated: 24-Mar-2011