Data

The Data page is where you import or enter all data for the current project. Each time you import a new file, the data (stations and observations) extracted from that file are added to the current project. You must select a project to be active, before you can access the Data page.

You can import Columbus 4 files, as well as Columbus 3.8.x.x files. Several third-party file formats are also supported, including:

  • OPUS XML and Text files
  • Google KML files containing latitude, longitude and height coordinates
  • Star*Net files containing many of the commonly used keywords
  • Trimble Data Exchange, SSF, SSK, WAVE and some limited JXL file data
  • TDS RW5 files
  • Ashtech "O" files
  • Leica Ski files containing GPS data
  • Topcon XML
  • NGS Bluebook "B" and "G" Files

After importing data (or without importing data) you can edit, add and delete station and observation data using the Station and Observation grids found in the lower half of the Data page.

When using the Stations grid, there is only one set of North and East coordinate values for each station. If you are working with Grid (State Plane) coordinates, you would enter them in the North and East columns. If you are working with a Local Plane coordinate system, you would use the same columns. Columbus knows how to interpret these coordinates based on the adjustment type setting you select in the Adjust page.

Latitude and longitude

Latitude and longitude must always be provided in DMS (degree, minute, second) units. For example:

N 40-10-15.123456 must be entered as: 40.1015123456
S 40-10-15.123456 must be entered as: -40.1015123456 (negative)

E 105-3040111111 must be entered as: 105.3040111111
W 105-3040111111 must be entered as: -105.3040111111 (negative)

Using observation grids

When using the various observation grids (for example, Horizontal Angle Set grid), you can enter up to three observations for each record (for example, hor angle, zenith angle and slope distance). If you did not measure one of these observations, simply leave the specific observation cell blank (for example, leave the Slope Dist field blank if you did not make that measurement).

Direction sets

For Direction sets, assign a unique number (Set Num) to all direction records that are part of the same set. This can be any number between 1 and 999999.

Entering data within the grids

When entering data within the grids, you will receive and error message if you make an invalid entry. Be sure to enter linear and angular measurements in the active linear pr angular units (as set up in Preferences). The exception to this rule are Latitude and Longitude as described above.

Field observations

  • Azimuth: An astro-geodetic azimuth usually obtained from solar or polaris observations
  • Direction: An alternative to horizontal angles. Minimum of two directions required to be in every set.
  • Bearings: A bearing (derived from an azimuth) or an average bearing (commonly obtained from Public Land Surveying System records within the United States). Set up Preferences to indicate true bearings or average bearings. You cannot mix both types in same network.
  • Horizontal Angle (turned to right): An alternative to the use of directions.
  • Zenith Angle: Where 90 degrees is equivalent to a vertical angle of zero.
  • Chord Distance: The distance from the instrument at the AT station to the target of the TO station (where Instr/Targ heights are measured). If the chord distance is a mark-to-mark distance, then set the Instr/Targ heights to zero.
  • Horizontal Distance” The local tangent plane distance (2D) from the AT station to the TO station. This is equivalent to using the corrected zenith angle and slope distance (measured from the AT station) to compute the horizontal distance where HD = sin(zenith angle) * slope distance.
  • Height Difference: The height difference between stations.
  • Local Delta North: A local north offset (often measured with a tape)
  • Local Delta East: A local east offset (often measured with a tape)
  • Local Delta Up: A local up offset (often measured with a tape). For projects with limited extent, this would be similar to an elevation change where minimal curvature is applicable.
  • GPS X, Y, Z: Vectors determined using GPS equipment.

Coordinate observations

Coordinate observations are useful when you don’t want to hold a station fixed, but you do want to constrain its movement by specifying its standard deviation or variance.

  • Latitude: A coordinate observation used in 2D and 3D geodetic adjustments.
  • Longitude: A coordinate observation used in 2D and 3D geodetic adjustments.
  • Height: A coordinate observation used in 1D and 3D adjustments.
  • North: A coordinate observation used in 2D and 3D Grid or Local Plane adjustments.
  • East: A coordinate observation used in 2D and 3D Grid or Local Plane adjustments.

Misc Observations

  • Geodesic Azimuth: Use when you know the geodesic azimuth between two points. The geodesic azimuth is the direction along the ellipsoidal surface between two points. It is rarely used.
  • Geodesic Distance: Use when you know the geodesic distance between two points. The geodesic distance is the distance along the ellipsoidal surface between two points. It is rarely used.

Note: Instrument and Target heights are not used in 2D Adjustments.