Now available, Version 7.5 of the most powerful and popular coordinate conversion tool available today now offers support for legacy ATS grid formats in addition to the existing support for Alberta Township System 4.1. There is also enhanced batch file processing features, such as a new batch interface for point data conversions and the ability to use an unlimited number of Desktop jobs in a batch conversion. These tools extend the power of the Calculator to enable geospatial data definition, manipulation and management across the user’s organization. Manage your mapping data easily, accurately and quickly with the tool that more companies depend on to make certain they have the correct data. With this latest version the Vector File conversion tab now supports spatial data from ESRI geodatabases, Oracle and PostGIS as well as the full functionality of the Geographic Translator: multi-file translation for Vector and CAD formats, including DWG, DGN, Shape, Tab, Google's KML and much more along with powerful batch tools.

Over the last seventeen years the Geographic Calculator has become the standard tool for coordinate conversion worldwide. You should have this product in your toolbox!

On a basic level, the Geographic Calculator converts individual coordinates, point databases, and map files from virtually any coordinate system, datum, and map projection, to any other.

You can transform between coordinate systems, calculate the distance and azimuth between coordinates, and calculate a coordinate at a specific distance and azimuth from known starting point. The Geographic Calculator also computes grid convergence, point scale factor, datum shifts, and grid shifts. Of course, the Geographic Calculator is professionally documented and supported.

Some of the great features introduced in Calculator v7 include:

• An extension enabling the use of the Calculator in ArcGIS
• Dockable windows
• Workspace settings that can be saved and shipped to other users
• Administrative tools that can be used to lock down editing of the coordinate
• Datasource to protect definitions and guide users
• Complete FLEXnet licensing for easier porting of licenses and WAN usage
• Dongle licensing
• A datasource merge tool
• The ability to transform between any datum (not just WGS84)
• And much, much more.

Features

Interactive Conversions

Select your source and destination coordinate systems, enter your coordinates, choose the datum transformation you would like to use, and then press the "Calculate" button. Yes, it's that easy! The Interactive conversion tab allows you to convert, forward a position, and calculate the distance and azimuth between two points.

Interactive conversions with the click of a button

Horizontal Time Dependent Positioning (HTDP)

Horizontal Time Dependent Positioning provides a means to predict and adjust for data transformations related to movements of the Earth's crust over time. When using Calculator, if both the source and target coordinate systems support HTDP, and have active specified dates, then an HTDP transformation will be created for use by the current calculation.

Horizontal Time Dependent Positioning

Point Database Conversions

A point database job allows you to perform coordinate conversion, forward and inverse and other calculations on your point database files. Work with flat files or files from a database such as Oracle, Sql, MS Access or any other ODBC type database. With a given distance and direction, you can easily compute coordinates from an origin, or the distance and azimuth between points. Load in data from a variety of file types and output back to that file type or send your results directly to AutoCAD DWG/DXF files.

The point database tab has excellent support for Oil and Gas exploration specific formats like SEG and UKOAA. The interface is extremely fast able to transform one hundred thousand records in 8 seconds or 50 million records in under an hour and a half. Users can easily work with large files by loading only a sample of the file to set up the job.

Additionally, you may:

• Load an existing spreadsheet/database file in dBase v.3-5, Excel XLS v.2-2000, or ASCII text files.
• Or use an ODBC Data Source to load data from Oracle, Postgres, SQL Server or another ODBC database. Spatial database support is available through our extension to ArcGIS. See below for more information.
• Perform coordinate transformation on a variety of Oil and Gas industry formats: SEG-P1, SEG-Y, UKOAA P1/90, and SPS
• Right-click to modify the grid: insert, delete, clear and rename columns, and insert or delete a row.
• Specify output coordinates display format.
• Define custom text file formats, including custom header information.
• Print the entire grid.
• Save the point database in dBase, Excel XLS, ASCII text, MS Access, or as an AutoCAD DWG/DXF R12 map file.
• You may read in and write out from and to any ASCII based format (not recommended for Oil and Gas formats).
• We even include SEGP1 text file support.

Convert point databases, including your own text file formats

Alberta Township System (ATS) Support

The Alberta Township System (ATS) is a surveying system used in parts of Western Canada including Alberta Province. It is a variation of the Dominion Land Survey (DLS). In the Blue Marble Desktop, ATS is supported using a string-based point style using the universal well identifier format. Included is support for Alberta Township System legacy grids, versions 2.1-2.6, 3.1. 3.2 NAD27, 3.2 NAD83, and version 4.1. Users can convert single points or files of points between the ATS system and any of our many geodetic or projected coordinate systems.

Alberta Township System Coordinate Point Definition

Expanded Database Support

Calculator now supports all ODBC databases permitting reading and writing to:

• MS Access
• MS SQL Server
• Oracle
• MySQL
• Postgres

Spatial database support is available through the extension to ArcGIS where we support ArcSDE, Geodatabase, and Personal Geodatabase. The addition of the Spatial Connect module provides access to ESRI geodatabases, as well as Oracle and PostGIS native spatial geometry types.

Expanded Database Support

Batch Point Database Conversions

The Batch Point Database Conversions option can be used to convert multiple similar point database files at one time. Set up one conversion and use that as a template to convert a group of files - just select the files to convert and run the process. The latest Calculator version also includes enhanced batch file processing features, such as a new batch interface for point data conversions and the ability to use an unlimited number of Desktop jobs in a batch conversion.

Projection Recovery Tool for Vector Datasets

This tool allows the user to assign coordinates to an image and perform projection recovery for unknown projections. If the reference coordinate system is not based on WGS 84, the tool can even transform through another datum before determining the unknown projection.

Projection Recovery Tool

Vector File Conversions

Convert individual vector and CAD files, batch process an entire folder from different formats and coordinate systems - AutoCAD DWG/DXF, Microstation DGN, ESRI Shapefile, ArcInfo Generate, E00, Google's KML, GML Simple Features, MapInfo TAB/MIF, Velocity files and much more are fully supported for both read and write.

Vector file conversions with a click of a button

The World's Most Comprehensive Coordinate Conversion Parameter Database

Over 12,000 coordinate system conversions are supported with pre-defined linear and angular units, ellipsoids, geodetic datums and coordinate systems. In addition, use our "two point fit" transformation and easy-to-use designers to create custom ellipsoids, datums, coordinate systems, and units.

Design your own coordinate systems

Best-fit polynomial method with Error Plot

View map files before and after conversion

Admin Tools

• New Administrative Tools allows you to control data source access
• Create Password based Access
• Restrict Data source overwrite

View map files before and after conversion

• Control view of objects: datum shifts, coordinate systems, ellipsoids
• Filter out unnecessary coordinate system objects
• Choose from all parts of a coordinate system
• Select objects for your area of work
• Option to 'Include' or 'Exclude' objects
• Define Geographic Envelope for Transformation Area

Point and click draw tool to create envelope

• Define acceptable datum shifts for said area

Project Manager

The project manager panel introduces the concept of workspaces, projects and jobs. Switch back and forth between multiple conversion projects. Save off a workspace and send it to other users to use your settings.

Project Manager

ArcGIS Extension

• Work with the Calculator in ArcGIS
• Switch between our data source and their PRJ files
• Define a coordinate system using BMG dialogues and generate a PRJ
• Pt to Pt conversion comparison
• Convert a point layer in calculator and add to Arc
• Use Admin conversion rules and add layer to Arc

ArcGIS Extension

Support of the new OGP WRS Registry

• Check for updates using color coding system
• Query an object for information on it
• Update your definitions

OGP WRS Registry Update Check

Additional Features

The Geographic Calculator also offers:

• USB Dongle Licensing option
• Area Calculation Tool
• Extended Coordinate System Support
• Hundreds of unit, ellipsoid, datum transformation, and coordinate system definitions, including many from standard government, corporate, and NPSG/POSC databases.
• The ability to design your own text file formats with an easy-to-use designer.
• Transformation to and from NAD27 in Canada using the Canadian National Transformation v2. We've even added the Double Stereographic map projection for our Canadian friends.
• Print enhanced reports with print preview.
• The Getting Started Guide provides a direct, project oriented approach to learning the capabilities of the Geographic Calculator

Details

Point Database Formats

• ODBC databases including:
  • Oracle
  • MySQL
  • MS SQL Server
  • MS Access
  • Postgres
• dBase
• Excel XLS
• ASCII text (including custom text file formats, UKOOA for example)
• SEGP184, SEGP190
• Write to AutoCAD DWG/DXF
• MS Access
• Shell Processing Support

GIS Data Type Support

• Write to MapInfo MIF
• Write to ESRI Shapefile
• Write to MapInfo TAB
• Write to Microstation DGN

Supported Input Vector File Formats

• AutoCAD support through AutoCAD 2010 (*.dwg, *.dxf)
• Blue Marble Layers (*.bml)
• Digital Line Graph (*.dlg)
• ESRI ArcInfo Export (*.e00)
• ESRI ArcInfo Generate (*.gen)
• ESRI Shapefile (*.shp)
• GML Simple Features - Version 3.1.1. See Note 1 below. (*.gml)
• Google Keyhole Markup Language (*.kml)
• GPX Data File (*.gpx)
• LiDAR Data Exchange - Version 1.0, 1.1 and 1.2. See Note 2 below. (*.las)
• MapInfo Import (*.mif)
• MapInfo Table (*.tab)
• Microstation Design (*.dgn)
• S-57 (*.000)
• Spatial Data Transfer Standard (*catd.ddf)
• TIGER/Line (*.rt1)
• Velocity File (*.txt)

  Note 1: Reading and direct transformation of GML data conforming to the Simple Features Profile conformance level Zero, and Simple Feature Collections in version 3.1.1 (support for 2.1.2 coming soon). The writer always writes to the Simple Features Profile. There is no firm limit to the size of file that can be read into the Viewer in Blue Marble Desktop, but if the GML file has coordinate lists exceeding one million characters, the odds of display issues will increase.

  Note 2: Reading, writing, and direct transformation of LAS version 1.0, 1.1 and 1.2 data is supported. It is not recommended that LAS datasets larger than 5MB be loaded into the Blue Marble Desktop Viewer.

Supported Output Vector File Formats

• AutoCAD write support through AutoCAD 2010 (*.dwg, *.dxf)
• ESRI ArcInfo Export (*.e00)
• ESRI ArcInfo Generate (*.gen)
• ESRI Shapefile (*.shp)
• GML Simple Features - Version 3.1.1. See Note 1 below. (*.gml)
• Google Keyhole Markup Language (*.kml)
• GPX Data File (*.gpx)
• LiDAR Data Exchange - Version 1.0, 1.1 and 1.2. See Note 2 below. (*.las)
• MapInfo Import (*.mif)
• MapInfo Table (*.tab)
• Microstation Design (*.dgn)
• Velocity File (*.txt)

  Note 1: Reading and direct transformation of GML data conforming to the Simple Features Profile conformance level Zero, and Simple Feature Collections in version 3.1.1 (support for 2.1.2 coming soon). The writer always writes to the Simple Features Profile. There is no firm limit to the size of file that can be read into the Viewer in Blue Marble Desktop, but if the GML file has coordinate lists exceeding one million characters, the odds of display issues will increase.

  Note 2: Reading, writing, and direct transformation of LAS version 1.0, 1.1 and 1.2 data is supported. It is not recommended that LAS datasets larger than 5MB be loaded into the Blue Marble Desktop Viewer.

Spatial Databases

The Spatial Connect Module supports:

• ESRI Geodatabase
• ArcSDE, Personal and File Geodatabase
• Oracle
• PostGIS

Coordinate Conversion Parameters

We include a comprehensive coordinate conversion parameter database that contains most common coordinate systems in use throughout the world. You can completely customize this XML file by adding or removing parameters. Currently, the coordinate conversion database contains:

• Over 3500 pre-defined coordinate systems
• Over 1200 datum shifts
• Over 400 horizontal datums
• Over 80 various unit definitions
• 14 prime meridians
• A dozen vertical datums

Common coordinate systems included:

• Bell Wire Center V & H (V & H)
• Earth Geopotential Model of 1996 global geoid model support
• Gauss-Kruger Modified, 3TM, and 6TM
• Japanese Grid 2000 coordinate system
• Maine Coordinate System 2000
• Military GridReference System (MGRS)
• New Zealand Map Grid
• US State Plane 1927 (both original and exact solutions)
• US State Plane 1983
• UTM (Universal Transverse Mercator) North and South zones
• World Geographic Reference System coordinate string support
• XYZ Cartesian Earth-Centered Earth Fixed (ECEF)
• Grids for Argentina, Australia, Austria, Bahrain, Belgium, Borneo, Columbia, Cuba, Egypt, England, France, Ghana, Greece, India, Iraq, Ireland, Italy, Japan, Minnesota, Netherlands, New Brunswick, New Zealand, Nigeria, Peru, Philippines, Qatar, Quebec, Romania, Veracruz, and many more.

Alberta Township System (ATS) Grid Versions

• 2.1 NAD27
• 2.2 NAD27
• 2.3 NAD27
• 2.4 NAD27
• 2.5 NAD27
• 2.6 NAD27
• 3.1 NAD27
• 3.2 NAD27
• 3.2 NAD83
• 4.1 NAD83

Map Projections

• Aitoff
• Alaska State Plane 27
• Albers Equal-Area Conic
• Azimuthal Equal Area
• Azimuthal Equal Area (Polar Aspect)
• Azimuthal Equidistant
• Azimuthal Equidistant (Polar Aspect)
• Behrmann
• Belgium 72
• Bipolar Oblique Conic Conformal
• Bonne
• Cassini
• Craster Parabolic
• Danish System 34
• Danish System 34 (1999)
• Double Stereographic
• Eckert I
• Eckert II
• Eckert III
• Eckert IV
• Eckert V
• Eckert VI
• EOV (Egyseges Orszagos Vetulet)
• Equal-Area Cylindrical
• Equidistant Conic
• Equidistant Cylindrical
• European Stereographic
• Fuller (Dymaxion)
• Gall Stereographic
• Gnomic
• Goode Homolosine
• Guam State Plane 27
• Hammer Aitoff
• HSO/RSO (Deprecated)
• IMW Polyconic
• Krovak
• Laborde
• Lambert Conformal Conic (1 parallel)
• Lambert Conformal Conic (2 parallel)
• Lambert Conformal Conic Extended
• Lambert State Plane 27
• Loximuthal
• McBryde-Thomas Flat-Polar Quartic
• Mercator
• Military Grid Reference System (Deprecated)
• Miller Cylindrical
• Mollweide
• New Zealand Map Grid
• Oblique Mercator Azimuth
• Oblique Mercator Two Point
• Orthographic
• Perspective Conic
• Polar Stereographic
• Polar Stereographic (Variant C)
• Polyconic
• Popular Visualisation Pseudo Mercator
• Quartic Authalic
• Robinson
• Sinusiodal
• Space Oblique Mercator
• Stereographic
• Stereographic 70
• Swiss Oblique Mercator
• Tilted Perspective
• Times
• Transverse Mercator (Gauss-Kruger)
• Transverse Mercator Extended
• Transverse Mercator Snyder
• Transverse Mercator South Oriented
• Transverse Mercator State Plane 27
• Two-Point Fit
• Universal Transverse Mercator
• V and H
• Van der Grinten
• Van der Grinten IV
• Vertical Perspective
• Winkel I
• Winkel II
• Winkel Tripel

Vertical Datums

• Canadian Vertical Datum CVGD28
• Local Geodetic Datum Ellipsoid Height
• *National Geodetic Vertical Datum of 1929 (NGVD29)
• *North American Vertical Datum of 1988 (NAVD88)
• GEOID03 model available for vertical datum transformations

Vertical Datum Transformation Methods

• Local Ellipsoid Height to/from Local Ellipsoid Height

  Bursa/Wolfe or Molodensky methods

• *NAD83 to/from NAVD88

  Geoid 96 model implementation

• *NGVD29 to/from NAVD88

  The NGS VERTCON method is used to compute the difference in orthometric height between the NAVD29 and NAVD88 vertical datums for a specific latitude and longitude (the appropriate orthometric height will be displayed after the conversion). VERTCON implements predetermined grid shifts (analogous to NADCON horizontal grid shift files) for any particular point on the grid. THIS METHOD IS ONLY VALID IN THE CONTERMINOUS UNITED STATES OF AMERICA FOR CONVERSIONS BETWEEN NGVD29 and NAVD88.

Horizontal Datum Transformation Methods

• Bursa/Wolfe
• Canadian National Transformation V2
• DMA MRE
• FD58 Datum (Final Datum 1958)
• HPGN
• Irish Grid polynomial datum shift to match OSi parameters
• JGD2000 Datum
• Molodensky
• Molodensky-Badekas 10
• NADCON
• OSTN02

NAD27 to NAD83 Conversions

NAD27 to NAD83 conversions (or vice versa) with the United States and associated territories are performed using exactly the same algorithm and data files as used by the National Geodetic Service's NADCON program. Results are numerically identical to those of NADCON. Version 2.0 of the Canadian National Transformation is fully supported for conversion within Canada.

NAD83 to HPGN Conversions

NAD83 to HPGN (NAD83/91 or HARN) conversions (or vice versa) are performed using the exact same algorithm and data files used by, and results are numerically identical to, the National Geodetic Service's NADCON program.

ArcGIS Extension

Geographic Calculator v7 now has the ability to recognize when a user has ArcGIS installed on their desktop. The Calculator will install a special toolbar in ArcGIS, enabling users to access Blue Marble features directly in ESRI's ArcGIS Software. This exciting new capability for Calculator extends the power of ArcGIS as a geodetic definition and geospatial management interface. Calculator can also load reference files from other applications and output PRJ files which can be used and displayed in ArcGIS. Blue Marble’s coordinate conversion technology is used worldwide by thousands of GIS analysts at software companies, universities, oil and gas companies, civil engineering, surveying, technology, enterprise GIS groups, government and military organizations.

ArcGIS Extension

The new Arc Extension allows users to work with the Geographic Calculator directly in ArcGIS. Some of the main features of this extension include:

• The ability to switch between geodetic definitions found in the Blue Marble GeoCalc XML data source and other geodetic definitions contained in existing ArcGIS
• Define and generate a custom PRJ using the Blue Marble coordinate system dialogues
• Load reference file info from 'application x', and output a PRJ file that can be used and displayed in ArcGIS
• Compare data conversion results from ArcGIS projects in Blue Marble.
• Convert a point layer in the Geographic Calculator and add it as layer in ArcGIS
• Use Blue Marble’s Administrative conversion rules and apply them for your ArcGIS or ArcMap users.
• ESRI Geodatabase conversions in the ArcGIS Extension for SDE, File Geodatabase, and Personal Geodatabase

Working with the Geographic Calculator directly in the Arc environment compliments the work that many Blue Marble users have been doing for years. Many GIS professionals double-check their coordinate conversion work in ESRI with Blue Marble’s Calculator to ensure data quality and consistency. However the latest new enhancements to the Calculator introduce new ways of extending the geodetic power of the ArcGIS environment. The new Administrative Tools in the Geographic Calculator allow users to define appropriate datum selection and thus datum shift by geographic envelopes. This will ensure that the GIS Administrator has control over conversion definition for project work in the Arc environment.

Who's Using The Geographic Calculator

We have hundreds of thousands of customers and users around the world, here are just a few:

• ExxonMobil
• Shell
• Chevron
• ConocoPhillips
• Halliburton
• BP
• British Geological Survey, UK Ministry of Defence
• NOAA NGA
• Department of the Interior
• Google
• Microsoft
• Landmark
• Harvard University
• Yale University

User Comments

"The software has exceeded all of our expectations regarding ease of use, intelligence and accuracy. The Calculator has also proven to interact well with additional software applications we use."

- B. Pelzmann BP

"The Geographic Calculator has allowed us to perform multiple adjustments and transformations using standard methods as well as customized localized parameters. The accuracy and speed of the Geographic Calculator have allowed us to move forward quickly with building the Bahamian NSDI and the technical support provided by Blue Marble has been outstanding in working through EPSG tables and other items."

- P. Rabley Bahama National GIS Center

"I have found the Geographic Calculator to be a very flexible and easy to use application. The range of conversion options are quite comprehensive. Exceptional technical support at all levels accompany this product nicely."

- P. Halton True North Surveys

"The Calculator plays a great part in the accuracy of our survey projects here in the United States and abroad. We use the NAD27 to NAD83 conversions on a daily basis; we find the Calculator accurate and easy to use!"

- T. Maultsby & P. Eick Conoco, Inc.

"Indispensable. When I'm converting large files from NAD 27 to NAD 83 there's no other program I'd rather have on my side. It should be in every GIS/GPS professionals toolbox!"

- M. Eustis Ashtech

"I've been looking for this app for years. It's very polished, very easy to use, and very reliable. The Geographic Calculator paid for itself the first day on the job!"

- K. Domingue Domingue, Szabo, and Associates

"This program is great! Really makes GIS data conversions a snap!"

- B. Anderson Ohio State University

"The Geographic Calculator worked beautifully when converting the coordinate systems of my vector map files. This product gives me accurate results, and it's easy to use. All of the features were in the right place."

- Dave Snyder Aero-Data

"Blue Marble's Geographic Calculator is indispensable for my research on the pre-Hispanic southwest. I use it to confirm archaeoastronomical alignments, to record spatial relationships between sites and to perform coordinate transformations. Geographic Calculator gives me the ability to quickly and efficiently explore different combinations of alignments. There is no substitute for it."

- Phillip Tuwaletstiwa Hopi

Frequently asked Questions

Q: Can I create my own custom datums within the Geographic Calculator?

Q: Can I create my own custom coordinate systems within the Geographic Calculator?

Q: What format input files can I use?

Q: Has the Geographic Calculator been well tested?

Q: How do I define a NADCON-based datum for Alaska or Hawaii?

Q: Can I integrate Geographic Calculator features into my own application?

Q: Will the Geographic Calculator convert coordinates from NAD27 to NAD83?

Q: Does the Geographic Calculator support the HARN/HPGN datum transformation method? What is the HARN/HPGN method?

Q: What is the NADCON Datum Transformation method? Can I use this method with the Geographic Calculator?

Q: I have a number of Latitude/Longitude coordinates (NAD83), with associated geodetic ellipsoid heights. Can I use the Geographic Calculator to derive MSL height from ellipsoid height?

Q: Which vertical datum transformation method is used by the Geographic Calculator and how accurate is it?

Q: How do I transfer a license from one computer to another?

Q: How do I transfer my floating license from one computer to another?

Q: How do I install and configure my network license for Geographic Calculator 6.3?

Q: Can I create my own custom datums within the Geographic Calculator?
A: Certainly, the Geographic Calculator supports custom datums based on Molodensky, Bursa/Wolfe, NADCON, HPGN/HARN, and the Canadian National Transformation datum transformation methods. You simply need to know the required parameters for your custom datum. The Geographic Calculator provides a simple datum designer that provides an interface for entering the required parameters for your custom datum.

All datum parameters are stored in an external coordinate conversion database, an ASCII file that can be shared between users and different Blue Marble applications.

Q: Can I create my own custom coordinate systems within the Geographic Calculator?
A: Yes, the Geographic Calculator supports custom coordinate systems based on any supported datum, map projection, and unit. The Geographic Calculator provides a simple coordinate system designer that provides an interface for entering the required parameters for your custom coordinate system.

All coordinate system parameters are stored in an external coordinate conversion database, an ASCII file that can be shared between users and different Blue Marble applications.

Q: What format input files can I use?
A: The Geographic Calculator supports point database files in Excel, Lotus, dBase and Text formats. You can also define your own custom ASCII file format. We have defined the SEGP1 file format as a custom file format and ship the definition with the Geographic Calculator as an example of how to define your own ASCII file format.

The Geographic Calculator supports map files in AutoCAD DWG and DXF (R2000 or earlier), MapInfo MIF and TAB (the native MapInfo format), and ESRI Shapefile (the native ArcView format) formats.

Q: Has the Geographic Calculator been well tested?
A: We have invested many person years in testing the coordinate conversion algorithms within the Geographic Calculator. We have also developed relationships with many organizations worldwide who have independently tested the product before deploying it within their businesses. The Geographic Calculator may very well be one of the most significantly tested geographic software applications on the market today!

Q: How do I define a NADCON-based datum for Alaska or Hawaii?
A: We don't ship the required NADCON grid shift files for Alaska and Hawaii with the Geographic Calculator. They are very large. You will need to download the files from our website. Once you have download the Alaska.zip and Hawaii.zip files you need to unzip them in the folder where the coordinate conversion database (geocalc.dat) resides, typically the data folder within the Geographic Calculator installation folder. Once you have downloaded and unzipped the grid shift files into the proper folder you need to use the datum designer in the Geographic Calculator to define a new datum.

Q: Can I integrate Geographic Calculator features into my own application?
A: Yes. Be sure to check out our GeoCalc component. GeoCalc is the underlying coordinate conversion engine within the Geographic Calculator.

Q: Will the Geographic Calculator convert coordinates from NAD27 to NAD83?
A: The Geographic Calculator can use up to 5 different datum transformation methods for this conversion:

• NADCON - the most accurate method for conversions within the U.S. and other territories wherein NADCON grid shift files have been created.
• Canadian National Transformation (NTv2)- the most accurate method for conversions within Canada.
• Bursa/Wolfe - a seven parameter transformation that can be highly accurate if appropriate parameters are used. Generally published parameters will generally yield inferior results to the NADCON or CNT V2 methods.
• MRE - a general polynomial "best-fit" method, not highly recommended unless you have other coordinate data converted using this method.
• Molodensky - a three parameter transformation. Generally published parameters will generally yield inferior results to other methods.

Q: Does the Geographic Calculator support the HARN/HPGN datum transformation method? What is the HARN/HPGN method?
A: Yes. The Geographic Calculator fully supports HARN/HPGN, and uses grid files in a format published and provided by the National Geodetic Survey.

HARN is an acronym for High Accuracy Reference Network, and HPGN is an acronym for High Precision Geodetic Network. These systems are designations used for statewide geodetic network upgrades. HARN is generally used to refer to either system. This upgrade is an improvement to the accuracy of NAD 83 datum, and is most frequently used with the State Plane 1983 Coordinate Group and systems. The HARN datum use GPS (Global Positioning System) observations that are the basis of grid shift files. In GeoCalc, these grid shift files are incorporated in to datum, and referenced during coordinate transformations.

HARNs are being established within the U.S. on a state-by-state basis by the National Geodetic Survey. HARNs have been established for 28 states and Puerto Rico and the Virgin Islands: Alabama, Arizona, California, Colorado, Florida, Idaho-Montana, Kentucky, Louisiana, Maine, Maryland-Delaware, Michigan, Mississippi, Nebraska, New England (CT, VT, MA and RI), New Mexico, Oklahoma, Tennessee, Texas, Virginia, Washington-Oregon, Wisconsin and Wyoming.

You can think of a HARN as a geodetic datum, most easily viewed as an enhanced NAD 83 datum. HARNs are also known as NAD 83/91 and High Precision Grid Networks (HPGN). The NGS HARN method is actually very similar to the NGS NADCON method. As with the NADCON method the shift values for a geographic area are stored in a set of grid files, one representing latitude shifts (named with the extension .las) and one representing longitude shifts (named with the extension .los). The major difference is that the HARN data files contain shifts from NAD 83 to a HARN instead of NAD 27 to NAD 83.

Q: What is the NADCON Datum Transformation method? Can I use this method with the Geographic Calculator?
A: The NADCON method transforms coordinate values between the North American Datum of 1927 (NAD 27) and the North American Datum of 1983 (NAD 83). The National Geodetic Survey (NGS) NADCON method provides a transformation that is accurate to within 0.15-0.5 meters and is highly recommended for NAD27 and NAD83 conversions within the U.S. and other territories. The NGS NADCON method applies a simple interpolation algorithm using a gridded set of standard datum shifts as parameters. The shift values for a geographic area are stored in a set of grid files, one representing latitude shifts (named with the extension .las) and one representing longitude shifts (named with the extension .los). The Geographic Calculator uses grid files in a format published and provided by NGS.

Q: I have a number of Latitude/Longitude coordinates (NAD83), with associated geodetic ellipsoid heights. Can I use the Geographic Calculator to derive MSL height from ellipsoid height?
A: Yes, the Geographic Calculator supports vertical datum conversions from local geodetic ellipsoid (NAD83) height to NAVD88 geoid height, which approximates mean sea level. This specific conversion is implemented using the Geoid 96 model.

Q: Which vertical datum transformation method is used by the Geographic Calculator and how accurate is it?
A: The National Geodetic Survey (NGS) VERTCON method is used to compute the difference in orthometric height between the NAVD29 and NAVD88 vertical datums for a specific latitude and longitude. VERTCON implements predetermined grid shifts (analogous to NADCON horizontal grid shift files) for any particular point on the grid. THIS METHOD IS ONLY VALID IN THE CONTERMINOUS UNITED STATES OF AMERICA FOR CONVERSIONS BETWEEN NGVD29 and NAVD88.

The VERTCON model is accurate to 2 cm (assuming that data collection methods are at least that accurate or better). Since most of the data used to calculate the model fall in the eastern United States, accuracies in that part of the country will tend to be better than elsewhere.

DATA REQUIREMENTS TO USE THE VERTCON VERTICAL DATUM TRANSFORMATION

• Data points must be within the conterminous 48 United States
• Conversion is ONLY valid for conversions between NGVD29 and NAVD88
• Data points must be on the NAD27 or NAD83 horizontal datum for valid transformations

Q: How do I transfer a license from one computer to another?
A: Please consult the License Manager Help for instructions on how to transfer a license. Access this help file from the Help section found on the main menu of the Geographic Calculator.

Q: How do I transfer my floating license from one computer to another?
A: You will find step by step instructions for doing this in our 'Installing and Configuring the Floating License' White Paper found here.

Q: How do I install and configure my network license for Geographic Calculator 6.3?
A: You will find step by step instructions for doing this in our 'Installing and Configuring the Network License for Geographic Calculator Version 6.3' White Paper found here.