updated: 24-Mar-2011

 Copan for Windows

Map Checks

Property (lot or parcel) boundaries on many maps, plans/plats or deeds are commonly annotated with azimuths (or bearings), horizontal distances, curve parameters, and areas. Bearing and distance pairs are often known as calls, courses, or metes. Copan refers to sequences of such reduced data as map traverse data and the process of checking the consistency of such data as map check. (Elsewhere, it may be known as closure check, lot check or deed check.)

Use this module to check the closures and areas (where appropriate) of any number of map traverses, including ones with curves, independently of any coordinate file. In fact, Map Check is disabled if a coordfile is open.

Note that if you need to adjust azimuth and distance traverse data or save new points, you should use the § Map Traverses module. Also, this module cannot be used for field data, involving horizontal or vertical circle readings or slope distances. For such needs, use the § Field Data Processing module. Finally, hile there are certain similarities between the Map Check 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 Check Bearing-Distance Traverses

1. If you have a coordfile open, close it.
2. Calculate | Check Brng-Dist Traverse (Map Check)...
3. Optionally Load... a traverse Data file. This may be an older-format loop file or a newer-format map traverse file (see Map Traverse Files below).
4. 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 a combined map projection and sea-level (or elevation) factor.
5. Enter or edit the bearing-distance traverse data in the big edit box. See below for a description of map traverse data for checking.
   To move the text cursor within the big edit 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.
6. Optionally List the map traverse Data.
7. Save the Data for reuse.
8. Optionally Reverse the direction of the map traverse Data.
9. Calculate (or OK) the traverses.
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 Check window.

click for larger view

2. Map Traverse Data for Checking

• Begin each traverse by a starter line, which must contain the first point number, under Start Pnt, and may contain a label, under Trav Label, identifying the traverse. Since there is no use of coordfiles, any valid point number may do.
• A traverse must have a sequence of leg lines. Each leg
  • must contain these three items: To Point number, Bearing (or azimuth) and Distance,
  • and may contain a Pnt Note (under Trav Label), Pnt Code, and a Curve Code. However, Pnt Notes and Pnt Codes are ignored.
• For a Bearing or Distance, an appropriate expression may be used (see § Bearing Expressions and § Distance and Offset Expressions), except that, because no coordfile is open, no point numbers may be used. If a Bearing or Distance is the same as the previous one, a double-quote character (") may be used for ditto.
• At any point along a traverse you may need to change the scale or distance factors or the azimuth correction. To do this, enter a separate line with
  • SF=value,
  • UF=value, or
  • AC=value
  under Conversion. From that point on the new value is used instead of the original head value. Optionally, a differential azimuth correction
  • da=value
  may be used, where the value is added to the current value for subsequent azimuth corrections. Or, a relative azimuth correction
  • ac=value
  may be used, where the value is added to the original head value for subsequent azimuth corrections. Note that these commands are case-sensitive.
• Blank lines may be used for readability but have no affect on traverse demarcation or calculation.

3. Map Traverse Files

• The first line must contain only this text:

      Map Traverses

• The next three lines can contain anything as they are not currently used.
• The next three lines must contain the head correction values — scale-factor, units-factor, and azimuth-correction — one each per line, respectively.
• Each subsequent line must be either a comment line or a tab-delimited data line with these six fields:

      point-num, bearing, distance, trav-label/conversion/pnt-note, pnt-code, and curve-code

  While some or all of those fields may be empty there must be five tabs per line. Which fields can be left blank depends on the purpose of the particular data line (see Map Traverse Data for Checking above).

• Single-byte character encoding, such as ANSI, DOS or UTF-8 must be used. Note: multi-byte character encodings (such as Unicode or UTF-16) will not work.

Example Map traverse file.

Map Traverses
1st dummy line
2nd dummy line
3rd dummy line
1.0000000000
1.0000000000
0.0000000000
1                       Parcel B
2   092.2112    160.40
3   182.0352    160.93
4   "           048.32
5   183.4005    059.19
6   260.5657    160.73
7   000.0812    061.41
8   002.1748    077.60
1   002.1748    161.24

4. 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.

5. Notes

• If you have multiple traverses, when you Calculate you may begin from a specific traverse rather than from the top by entering the start point number or traverse label.
• When you Calculate, Copan always checks and computes the traverse data currently in the edit boxes.
• Changes to the data in the edit boxes are only saved (to disk) when you Save Data.
• After you Calculate, Copan lists the reduced traverse data (i.e., legs are in their combined interpreted and converted form).
• If a traverse is a loop (i.e., it ends on its own start point) Copan provides the enclosed area in squared distance units. And if a units factor was involved, the area is also given in converted units. For example, if distances are entered in feet and a UF=0.3048 conversion is entered, then area is given in m² and in ft².
• Copan does not calculate areas that are only enclosed by separate different traverses, but it does still calculate all the other paramaters of any non-loop traverses.
• If Copan complains about the data when calculating, and you cannot see what is wrong, visually inspect the data by selecting it all with the mouse cursor. Often, you can see the inconsistency via the selection block outline.
• If you List traverse data to the Info Display file,
  • multiple blank lines are ignored, and
  • azimuth (or bearing) and distance expressions or dittos are shown in their interpreted form (i.e., expressions are evaluated), but not in their converted form (i.e., AC, SF, UF are not yet applied).
• List All... is equivalent to the sequence List data and Calculate.

updated: 24-Mar-2011