FAQ


Compatibility With Previous Versions

Q: What operating systems can I run Columbus 4.5 on?
A: Microsoft 64 bit Windows 7, 8 and 10.


Q: The Columbus file keywords used in Columbus 3.X have changed in Columbus 4.5; can Columbus 3.X data files be imported into Columbus 4.5?
A: Yes. Most keywords from Columbus 3.X are supported in Columbus 4.5.

Please note that in Columbus 4.5:


Q. What should I do if I am having trouble importing a Columbus data file (3.X or 4.5) or 3rd party data file?
A. When you encounter problems importing a data file, please contact us at your earliest convenience at support@bestfit.com. Include (or attach) to your email the problem data file. We support several input file formats from different vendors. It’s quite possible that you file contains a data field that we are not currently supporting. Gaining access to your file will streamline the process of fixing the issue. We will treat your data file confidentially. We never release customer info or data files to anyone.


Q: What enhancements have been made to the Columbus 4.5 network adjustment engine that were not found in Columbus 3.X?
A: The Columbus 4.5 network adjustment engine adds support for:


Q: How do you ensure quality control from one release to another – assuming you will be doing many small releases?
A: Good question! As we build out Columbus 4.5, we create individual test files that exercise non-user interface code, each of which generates a report. When we determine the report is correct, we give it “Golden” status. Before each release, we run all tests (an automated process) and compare the new results against the golden results. If nothing unexpected has changed, we are good for release. If any report changes are detected, we perform a manual inspection to determine if the change is warranted. To date, we have about 200 different network tests, and the list is growing. We are always looking for additional network files to add to our quality control. If you have a network you would like to add, please send it to support@bestfit.com. Your data will be kept confidential. One of the reasons we chose a “light” user interface for Columbus 4.5 is to improve reliability and lessen the chance of introducing problems when the software is updated. A straight-forward user interface is the best way to control quality year after year.


Setting Up Preferences

Q: How do I set up a UTM (Universal Transverse Mercator) zone in Columbus 4.5?
A: The UTM zone is based on the Transverse Mercator projection with its N-S origin at the equator and E-W origin at six degree longitude intervals.

To set up a UTM zone in Preferences (for interactive adjustments), enter the Preferences Page, Grid Projection tab. In the drop down grid list select “UD (user defined) Transverse Mercator,,,”, then fill in the Transverse Mercator edit boxes with these values:

CM: -111.0 for western longitude zone 111.0 west which covers 108.0 to 114.0 west longitudes. Western longitudes are always entered as negative.
SF: 0.9996 for scale factor
CP: 0.0 for central parallel (equator)
FE: 500,000 meters for false easting
FN: 0.0 for false northing

When adjusting by file (Adjust File page), add this line to your input data file:

_ADJUST_GRID_TM_PARMS; -111.00; 0.9996; 0; 500000.0; 0


Network Adjustment

Q: How large can my project extend when performing a Local North, East, Elevation adjustment?
A: We recommend the project span no more than one square kilometer. For larger projects, use a Grid or Geodetic adjustment.


Q: How do I capture and save the adjusted coordinates after a network adjustment?
A: After the network adjustment has completed, enter the Coords tab and click Keep (on the far right). Then select the stations for which you want to update the coordinates (with the adjusted coordinates) and click OK. The coordinates will be updated in memory only, so be sure to save the current project to a data file.


Q: How can I apply global deflection of the vertical settings for all stations in my network?
A: Deflection of the vertical settings (entered in seconds) allow Columbus to apply corrections to terrestrial measurements (azimuths, directions, bearings, horizontal angles and zenith angles). These corrections account for the differences between observations leveled in the direction of gravity and observations leveled in the direction of the ellipsoidal normal (used in geodetic computations). For high-accuracy surveys, you should strive to apply these corrections when using these terrestrial observations.

Columbus 4.5 allows you to provide deflection of the vertical values for each station. However, there may be times when you simply want to set all stations (at adjustment time) to have the same Deflections of the vertical settings (deflections in N-S and E-W). To establish a global setting, go to the Preferences page and select the Overrides tab, then the Others tab. Enter a non-zero value in the Defl N-S and Defl E-W fields. If you want to set the global Deflection values to zero, you must enter a very small number in each field (for example, 0.001 seconds). Entering zero means no global default will be set, resulting in the current deflection of the vertical settings at each station (if any) to be used.

This technique can also be applied when computing traverses and inverses on the Tools page.


Q: I am working on a project using orthometric heights. However, I want the computations based on ellipsoidal height. What are my options?
A: An adjustment based on ellipsoidal height vs. one based on orthometric height will affect the results. This is due to the fact that between any two stations on the ground, the distance between these stations varies with height. For example, if station AA has a height of 3000 meters and station BB has a height of 2500 meters, the slope distance between these two stations will be 587.547 meters (based on a known lat and lon for each station and the NAD 83 datum). If these two stations were lowered by 2500 meters (AA to 500 meters and BB to 0.0 meters), the slope distance between them would become 587.483 meters (a difference of 0.064 meters). Clearly, the height of an adjustment will affect the results in terms of the Lat, Lon or North, East coordinate components.

Option 1:
One option is to ensure all your control stations (1D or 3D) have known ellipsoidal heights and that you adjust based on ellipsoidal height.

Option 2:
A second option is to base the adjustment on the known orthometric heights and provide an average geoid height to the project area. During adjustment, Columbus will add the average geoid height to each station’s orthometric height to obtain a station pseudo-ellipsoidal height. These pseudo-ellipsoidal heights will then deliver results nearly identical to an adjustment based on known ellipsoidal heights. At reporting time, the adjusted orthometric heights will be presented by simply subtracting the average geoid height from the pseudo-adjusted ellipsoidal heights.

To set up Option 2, from the Preferences page select the Advanced tab. Enter a non-zero approximate geoid height for the project area in the Approx GHgt field. Then, base your adjustment on orthometric height.

This technique can also be applied when computing traverses and inverses on the Tools page.


Q: I want to perform a 2D network adjustment using the actual known heights for each station. I don’t want to use a mean height for the entire project, since the vertical terrain varies by thousands of feet between some stations. Can I do this?
A: Yes! If you are working in terrain that varies greatly, but want to perform 2D adjustment (using actual or approximate heights for each station) you need to select one of the 2D Network Adjustment types from the Adjust page and select the 2D Station Height. Be sure you have also provided approximate heights for every station in the network.

Why would you want to use this feature? One scenario is if you are getting poor results with a 3D adjustment due to height related observations (for example, zenith angles) that are distorting your results. If all you require are adjusted 2D coordinates, eliminating the affects of zenith angles may improve your adjustment. You still include the zenith angles in the adjustment, but the vertical corrections due to these angles are ignored.


Q: How can I set up a default standard deviation for all my horizontal and zenith angles in my current project?
A: Before adjustment, go to the Preferences page and select the Overrides tab. In the Hor Ang and Zenith edit box, enter the desired default value in seconds (values dependent on the active angular units). At adjust time, non-zero values will override observation-specific standard deviation values set up in the Data page.


Q: I need to perform my adjustment using UTM grid. How do I set up the grid parameters?
A: Prior to adjustment, set up the UTM grid and make it active. On the Preferences page, select the Grid Projection tab. Change the Grid Projection type to UD Transverse Mercator (User-Defined, near top of list) and enter the applicable UTM zone parameters in the Transverse Mercator column. For example, to set up zone 10 (western U.S.), enter the following:

Central Meridian: -123.0 (western longitude)
Scale Factor: 0.9996 (same for all zones)
Central Parallel: 0.0 (same for all zones)
False Easting: 500000.0 meters (same for all zones)
False Northing: 0.0 (same for all zones)

You can also set up custom TM zones (3TM, etc.) using this same procedure and providing zone-specific information to each of the fields above.

To obtain Grid results during adjustment, you must use one of the Grid or Lat, Lon adjustment modes (2D or 3D) set up in the Adjust page.


Q: I can solve a network interactively (modifying Preferences, Station and Observation data, Fix stations, etc.) or from a fully defined input file. When might I choose one method over another?
A: There are two ways to perform network adjustments: interactively or from a file.

Interactively: If you want to save your observations, adjusted coordinates and preferences to disk, you will probably be performing adjustments interactively (although it’s not required). This is the most common approach, since you need not have any knowledge of the multiple input file keywords available.

From file: Adjusting by file gives you the freedom to completely define your adjustment (with all settings) in a text data file. If you never change the file, adjustment results will always be the same. When adjusting by file, you simply enter the Adjust File page. From here, simply select your input data file and Columbus will load then adjust the network defined in that file. Adjusted reports are generated onscreen and the same results can be viewed in the user interface grids. However, adjusted coordinates cannot be saved to the original input file (most users don’t usually modify the original input file). If you need to modify the adjustment settings, simply edit your input file using an external editor such as notepad, then load and adjust the network file again.

For a list of all file-defined adjustment keywords and sample input files, go to Sample Network Files and Input File Keywords


Data Management

Q: Which StarNet file keywords does Columbus support on Import?
A: We support the following keywords in your StarNet data files. Please reference your StarNet documentation for their meaning:

# (pound sign)
- (dash or minus sign)
‘ (apostrophy)
\ (slash)

AT-FROM-TO, FROM-AT-TO, EN, NE

FEETINT, FEETUS, METERS
CSECONDS, DMS, GONS, MGONS,

NEGATIVEWEST, POSITIVEWEST, TURNS

DEFAULT, FACTOR, STDERRCORR, USE, WEIGHT

A, B, BM, C, CH, D, DV, E, EH, M, P, PH, SS, V
TB, T, TE
DB, DE, DM, DN
L

G0, G1, G2, G3
.2D, .3D, .3REDUCE, .DATA, .DELTA, .LONGITUDE, .LWEIGHT, .ORDER, .SCALE, .SEPARATOR, .UNITS, .GPS