landgate / datumspreadsheets

Excel spreadsheets to assist with data transformation, conversion and geodetic computations

Datum Spreadsheets

Excel spreadsheets to assist with :

• transformation of spatial data between geodetic datums (e.g. GDA94 to GDA2020)
• conversion of coordinate systems (e.g. Geographic (lat, lon) to Cartesian),
• projection of data to a map grid
• common geodetic computations (e.g. azimuths, distances)

Detailed information about these spreadsheets and the geodetic operations they support is contained in the Geocentric Datum of Australia 2020 Technical Manual www.icsm.gov.au. More general explanations of the concepts and terminology are available at the ICSM Fundamentals of mapping site www.icsm.gov.au/mapping/index.html

// Coordinate Transformations //

• Transformation_Conversion.xlsx: 7-parameter similarity transformation and coordinate conversion between Cartesian and Geographic coordinate systems.

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// Coordinate Conversions //

• Krueger n-series.xlsx: Geographic to Grid and Grid to Geographic (recommended for working outside beyond a single MGA / UTM zone).
• Krueger lambda series.xlsx: also known as Redfearn's equations. Accurate within a single MGA / UTM zone.
• Transformation_Conversion.xlsx: 7-parameter similarity transformation and coordinate conversion between Cartesian and Geographic coordinate systems.

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// Ellipsoid Computations //

• Vincentys.xlsx: Direct and Indirect methods to calculate accurate geodetic positions, azimuths and distances on the ellipsoid.

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// Grid Calculations //

• GridCalc_GDA94_NSW.zip: contains GridCalc_GDA94_NSW.xlsm (macro enabled spreadsheet) and GridCalc_GDA94_NSW_UG.pdf (user guide).

  GridCalc_GDA94_NSW.xlsm provides output of various geodetic quantities between two points given input of the MGA94 co-ordinates, AHD values and MGA zone of two points within New South Wales.

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// Geodetic Calculations // Perform Bulk transformations, projections and geodetic calculations directly in excel. Functions include: Vincenty Redfearn Decimal degrees >> Hours Minutes Seconds, Hours Minutes Seconds >> Decimal Degrees 7 Parameter transformations GDA2020 >> GDA94, GDA94 >> GDA2020

• The Geodetic-Calculations-v4.xlsm spreadsheets demonstrates the functions
• Geodetic-Calculations-v4.xlam the functions demonstrated in Geodetic-Calculations-v4.xlsm are available as an excel add-in. This can be referenced to excel and the functions can then be used in any excel spreadsheet.
• Geodetic-Calculations.bas Contains the vba code that can be imported into any project.

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