(The Input / Output module is required for this procedure.)
This procedure is used to create and edit a Traverse file, and carry out any of the following traverse adjustments:
- Bowditch
- Crandall's
- Transit
- Elevation Adjustment
The resulting adjusted co-ordinates or elevations may then be transferred to the currently open data base.
- Ensure that there is a data base open.
Refer to the procedures for creating or opening a data base. - Use the Utilities/Configure/Earth Constants commend to check that the Earth Constants settings
are correct. Refer to the procedure for Configuring Earth
Constants.
These values will be used if curvature & refraction correction or mean sea level correction are applied during the extraction or adjustment process. - Select the Field Transfer task.
- Select the Settings/Instrument command and use the Instrument dialog box to ensure that the theodolite vertical circle type is correctly set to match the theodolite used, and also to set the default standard deviations for the observations. These default standard deviations will be used for computing standard deviations in a traverse report.
- Select the Settings/Tolerances command and use the Tolerances dialog box to set the tolerances used by the system to generate warnings in the adjustment report if the adjustments to observations are outside the maximum standard deviation tolerance set.
- Select the Resolve/Traverses command to display the Traverse File Editor. An empty traverse file will automatically be opened in the traverse file editor.
- Use the View Menu to govern what is displayed and whether point identifiers are to be automatically generated when entering data in the Traverse File Editor. The Options may be changed at any time.
- If desired, use the File/New command to create
and open a different traverse file.
Alternatively, you may wish to use the File/Open command to open a different traverse file that you had already created and done some work on.
You may also use the Edit/New Traverse command to create additional traverses within the open traverse file. This allows multiple independent traverses, or nesting of successive traverses which are reliant on each other. - If there is a Field File containing traverse observations
that you wish to adjust, use the File/Extract
command to extract the traverse observations from the selected field file, into a currently viewed
traverse or a new traverse.
The Field file may have been created manually using one of the following Field Transfer/Input/Manual Entry commands: Alternatively, it may have been created automatically from a Raw file using the Resolve/Create Field File command.
The traverse observations that will be automatically extracted from the field file to the traverse file consist of the following:
- Observations to an instrument set up point in the traverse;
- Observations to a fixed point of known co-ordinates at the start or end of a traverse;
- Observations to a reference object of unknown co-ordinates but of known bearing at the start or end of a traverse.
Note that slope distances in the field file are reduced to horizontal distances which are passed to the traverse file. Height differences extracted directly are passed to the traverse file unchanged. However height differences will also be computed if a traverse observation contains a slope and slope distance. If requested, these computed height differences are also corrected for curvature and refraction using the settings in the Earth Constants dialog box before being passed to the traverse file. - You may use the Edit Menu at any time to insert, delete, clear, cut, copy or paste rows in the editor. First, highlight the appropriate record by clicking the row number.
- Use the Traverse File Editor to add to, delete, or edit the traverse observations. Refer to
the Traverse File Editor topic for details on editing traverse
file data.
Note that it is advisable to use the File/Save command at regular periods when entering data to minimise possible loss of data in the event of hardware or power failure. When editing is complete, you should again use the File/Save command, and you may wish to also use the File/Print command to send the contents of the control file to the Windows Print Manager. - Carrying out the Traverse Adjustment or Computation
Horizontal
First, ensure that the traverse observations are in correct order around the traverse, and that co-ordinates are present for the starting and ending traverse points for independent traverses. Co-ordinates in the database may be copied to the traverse file using the Edit/Retrieve Co-ordinates command.
If the observation at the first traverse point is an angle observation from a reference object, ensure that the preceding row contains either:
-the reference object identifier in the At column with its co-ordinates in the East and North columns;
or
-the traverse point identifier in the At column, the reference object identifier in the To column, and a bearing (traverse point to reference object) in the bearing column.
Similarly, if the observation at the last traverse point is an angle observation to a reference object, ensure that the following row contains either:
-the reference object identifier in the At column with its co-ordinates in the East and North columns;
or
-the traverse point identifier in the At column, the reference object identifier in the To column, and a bearing (traverse point to reference object) in the bearing column.
If the observation at the last traverse point is a bearing observation to the closing point, ensure that the following row contains:
-the closing point identifier in the At column with its co-ordinates in the East and North columns;
Ensure that Radius values are present for any traverse observation defining an arc. This will ensure that the arc segment area is included in the area calculation. For any such observations, use the Edit/Set as Arc command to set whether the distance is an arc distance or a chord distance.
Ensure that any radiation observations which are not part of the traverse are identified as such by using the View/Set Radiation command.
Select the Compute/Traverse command.
- Use the Corrections button to control the corrections that will be applied in the distances in the adjustment.
- Use the Report button to control the report that will be generated.
- Use the Settings button to control the minimum accuracy warning settings, and the positioning of bearing and distance text objects to be created in the project.
- Select the Angular Misclosure option to calculate the angular misclosure and generate adjusted or unadjusted bearings in the Bearing column.
- Select the required horizontal adjustment technique from:
- None
- Unadjusted
- Bowditch
- Transit
- Crandall's
- Select whether you wish to adjust angles and/or elevations.
- Select OK to do the adjustment.
Vertical:
First, ensure that the Elevation Differences are in the correct order along the traverse, and that there is an elevation present for the first and last traverse points for independent traverses. Elevations in the database may be copied to the traverse file using the Edit/Retrieve Co-ordinates command.
Use the Compute/Traverse command and with the Elevations option to do the adjustment.
When the process is successfully completed, an appropriate report is produced and you have the opportunity to update the traverse file with the resulting elevations. Refer to step 13. - Updating the Data Base.
After an adjustment is successfully carried out, the appropriate Report is displayed. Note that you may send the adjustment report to the Windows Print Manager, or save the report to a text file.
When exiting the report screen, you have the option of saving the resulting co-ordinates or elevations in the Stations window. If you are satisfied with the results, then select yes when prompted with "Update Co-ordinates into spreadsheet".
Once you have done this update of the spreadsheet, you are in a position to update the database. Use the Update command to update the co-ordinates or elevations in the database with the values in the traverse file.