updated: 21-Sep-2010

 Copan for Windows

COGO Calculations

Using Copan's COGO — coordinate geometry — calculator you can do many different computations involving bearings (or azimuths), distances (or ranges), offsets, angles, and coordfile points.

Note that to do freestation calculations, use the § Field FreeStations Processing module.

To COGO

• Calculation | COGO... or CoGo Lite.

• CoGo Lite has all of the same functionality as has COGO except the ability to use an Azimuth Correction or Scale Factor or to view and enter point Names, Codes and Notes.
• Distances are all horizontal (not sloped).
• When entering bearings, distances and offsets, you may use bearing and distance expressions (see § Bearing Expressions and § Distance and Offset Expressions), or you can select a previously entered or computed value from the drop-down lists.
• An offset is a (relatively small) optional distance perpendicular to a given bearing — positive right and negative left.
• An intersection line may be specified as being offset from and parallel to a given point and bearing by entering an offset expression (see § Distance and Offset Expressions) along with the point and bearing.
• If you select Auto increase To #, you should not need to enter a new To# (unless you'd like an alternative to that provided). Copan will automatically provide an unused To# when a From# is entered.
• Use the To --> From button if you wish to transfer the just-calculated To point # to a From point #, ready for another calculation.
• If entering a Note (not in CoGo Lite) for a new point, you can select a previously entered value from the drop-down list.
• If desired, use an Azimuth Correction (not in CoGo Lite) to adjust a bearing: Enter an angle, optionally negate it via –AC, then Apply it to convert the current contents of the Bearing box or boxes.
• If desired, use a Scale Factor (not in CoGo Lite) or Units Factor to scale a distance and offset: Choose a factor, optionally invert it via 1/SF or 1/UF, then Apply it to convert the current contents of the Distance and Offset box or boxes.
• You do not need to save the coordfile — in fact there is no Coordfile | Save menu item — because whenever you add or update points, Copan updates the coordfile instantaneously, wherever it is stored.

1. To do a Direct (or traverse) Calculation
(compute new point using bearing, distance and offset from existing point)

• Click the Direct / Inv radio button.
• Enter the From point #.
• Enter the Bearing.
• Enter the Distance and Offset, one of which may be blank or zero.
• Enter the new To point #.
• Calculate or OK. The new point will be added.

To do a long sequence of direct calculations — especially if you wish to adjust the traverse for closure — use the § Map Traverses module.

To do multiple direct calculations from one to many points, use the § Field Bearings Processing module.

2. To do an Inverse (or join) Calculation
(compute bearing, distance and offset between two existing points)

• Click the Direct / Inv radio button.
• Enter the From point #.
• Enter the To point #.
• Optionally, enter a Bearing constraint or an Offset constraint.
• Calculate or OK. The bearing and distance will be computed. If you entered a bearing or offset constraint, the bearing, distance and offset will be computed.

To do a long sequence of inverse calculations between successive points, use the § Area and Perimeter Calculations module.

To do multiple inverse calculations from one to many points, use the § Multiple Inverse Calculations module.

3. To do a Bearing-Bearing (or line-line) Intersection
(intersect bearings from two existing points to new point)

• Click the Intersection radio button.
• Enter one From point # (in either of the two From boxes).
• Enter the relevant Bearing and optional Offset (in the same line).
• Enter the other From point # (in the other From box).
• Enter the relevant Bearing and optional Offset (in the same line).
• Enter the new To point #.
• Calculate or OK. The distances, or distances and offsets, to the new point will be computed and the new point will be added.

4. To do a Distance-Distance (or arc-arc) Intersection
(intersect distances from two existing points to new point)

• Click the Intersection radio button.
• Enter one From point # (in either of the two From boxes).
• Enter the relevant Distance (in the same line).
• Enter the other From point # (in the other From box).
• Enter the relevant Distance (in the same line).
• Enter the new To point #.
• Calculate or OK.
• Choose which of the two solutions you require. The bearings to the new point will be computed and the new point will be added.

5. To do a Bearing-Distance (or line-arc) Intersection
(intersect bearing from one point and distance from another, to new point)

• Click the Intersection radio button.
• Enter one From point # (in either of the two From boxes).
• Enter the relevant Bearing and optional Offset (in the same line).
• Enter the other From point # (in the other From box).
• Enter the relevant Distance (in the same line).
• Enter the new To point #.
• Calculate or OK.
• If necessary, choose which solution you require. The missing dimensions to the new point will be computed and the new point will be added.

6. To do an Angle Calculation
(compute corner angle at one point, between two others)

• Click the Angle radio button.
• Enter the at point # in the At box.
• Enter the from point # in the From box.
• Enter the to point # in the To box.
• Optionally, click Angle Left if you need the counter-clockwise angle.
• Calculate or OK. The bearings and distances from the at point to the from and to points will be computed.
• The resulting horizontal angle is shown under the two Bearings (and by default is clockwise from From, to To, at At).

To do multiple angle calculations at one point, from one reference point, to many points, use the § Multiple Inverse Calculations module.

updated: 21-Sep-2010