... because the Earth's not flat

Getting Started with Geoida

The following topics summarise the steps required to perform various processing operations in Geoida:

Create a new job

A job must be created or opened prior to any data operations

• Select File -> New Job
• Enter details of job configuration

Survey processing

Survey data processing consists of two major stages: 1. Defining control stations, and 2. Reducing the observation data.

1. Control point setup
   • Enter control point details - select Points -> Enter Points (E/N) or Enter Points (Lat/Long) and mark as Fixed
     
   
   
2. Survey processing
   • Radiations option - enter data and reduce
     
     
   • e-Data option - set data format, select data file and define settings required, then
     • Traverse/Network setting
       • No adjustment or Bowditch adjustment - reduce data as-is
       • Least Squares adjustment
         1. Provisional points must exist, create by any of:
            • Points menu -> Enter Points (E/N) or Enter Points (Lat/Long)
            • Points menu -> Digitise Provisional Points
            • Prior reduction with None or Bowditch adjustment setting
         2. Compute - set to LS Network adjustment
     • Radiations only setting - reduce radiations after traverse or network is adjusted
     
     
   • Traverse option - enter data, then
     • No adjustment or Bowditch adjustment - reduce data as-is
     • Least Squares adjustment
       1. Provisional points must exist, create by any of:
          • Points menu -> Enter Points (E/N) or Enter Points (Lat/Long)
          • Points menu -> Digitise Provisional Points
          • Prior reduction with None or Bowditch adjustment setting
       2. Compute - set to LS Network adjustment
     
     
   • Least Squares Network Adjustment option
     1. Observation data entry
        • Manual data entry
          1. Enter observation data
          2. Select points required (must exist)
        • Load pre-defined observation data (eg Extract file from other Survey menu options, manual Traverse data, or digital terrestrial or GPS/GNSS observations) - points will be automatically loaded
     2. Set options and reduce

Transformation

Transformation of coordinate data requires firstly that a suitable transformation be defined for the current data location and datum.

1. Define transformation in Definitions -> Transformations option
   • Existing - check if there is an existing transformation suitable for use as-is
   • New - define a new transformation as follows:
     • NTv2 Grid File transformation
       1. Acquire grid file required for data location
       2. Define new transformation using acquired grid file
     • Other transformation types - Define as required
   
   
2. Apply to data
   • During importation of point data - Points -> Import
   • Whole job - Points -> Transform Job
   • Apply to exported data - Points -> List Points / Export

Interpolation of geoid

Geoid interpolation requires the correct definition for both location and datum.

1. Check Interpolation Method in Job Configuration
   • Fixed-point triangles setting - must run Points -> Form Geoid Model prior to interpolation
   • AUSGeoid (bilinear/bicubic) settings - acquire appropriate geoid grid file if necessary
   
   
2. Computation of gravity values
   • Survey menu reduction options - values are interpolated during processing
   • Points imported, entered via Enter Points or manually entered - use Points -> Interpolate Geoid Values in Window