May 19, 2021

GeoTalks Express Managing 3D Coordinate Systems using Global Mapper and Geographic Calculator Questions and Answers

Thank you for attending the GeoTalks Express webinar, Managing 3D Coordinate Systems using Global Mapper and Geographic Calculator. Registered attendees for this webinar should have received an email granting access to the recorded presentation posted on our YouTube channel.

Is the training free?​

We offer a few different training classes as well as a basic self-training guide. The public training classes we offer are in an online format and we have options for Global Mapper training, Lidar Module training, and Applied Geodesy training for Geographic Calculator. For more information on the training classes we offer, please contact our training team at

Will we receive a certificate after the webinar?

Certificates are distributed to users who attend our public training classes. For more information on the certificate requirements and our training program, please contact our team at

Does Geographic Calculator require a separate license?

Yes, Global Mapper and Geographic Calculator are separate programs that require separate licenses. With both of these programs installed and licensed on a machine you do have the opportunity to connect them with GeoCalc Mode in Global Mapper to manage 3D systems as shown in the webinar. 

What is the exact application use of Geographic Calculator? Does the latest version of Geographic Calculator work with previous versions of Global Mapper?​

Geographic Calculator is a program designed for advanced coordinate system management and transformation. Geographic Calculator and Global Mapper can be installed on the same machine and operated separately. 

In order to link the programs through GeoCalc Mode in Global Mapper you need to be working with compatible versions of the programs. The best option would be to make sure you are using the current release version for both Geographic Calculator (2020 SP1) and Global Mapper (v22.1).

Can I convert LAS files from ITRF08 to NAD83 CGVD2013?

You can convert LAS files in Global Mapper with GeoCalc Mode by reprojecting and exporting the data. You can also transform a LAS file in Geographic Calculator with a Vector Data Conversion job. To search for specific transformations you can look through the Geographic Calculator transformation datasource or explore transformations and systems on GeoCalc Online

I heard NOAA is introducing a new set of Vertical/Horizontal datum in 2022. How would that affect the old versions of the datums?

The new vertical component set to be rolled out in 2022 will show as new a new vertical datum in the Geographic Calculator datasource. The new object will be a distinct vertical datum and vertical system separate from the current NAVD88 definitions. 

Can this transformation be used to transform point clouds created from Pixel to Points?

Once you have run the Pixels to Points tool in Global Mapper and generated the point cloud, it can be exported to a lidar format and worked with or transformed like any other point cloud. 

Can you address the importance of keeping the various geoid models with the compatible horizontal datum?

As more data is collected and refined models and systems are adjusted and updated. Keeping up with the systems created by national survey authorities helps to keep your data accurate and relevant to the current standards. 

Can Geographic Calculator be used to create user defined coordinate systems?

Yes, users of Geographic Calculator can define their own coordinate systems and transformations as needed. 

Can we combine TLS generated point cloud data with UAV point cloud data in Global Mapper to create a 3D model?

Point cloud datasets can be easily combined into a single file in Global Mapper by loading them into the same workspace and then exporting all the data together. 

Similarly, if you would like to perform analysis processes on multiple point clouds together, load them into the same workspace and with all the source layers enabled and visible proceed with the processing. Global Mapper will by default consider all visible data. 

​Can you illustrate NAVD88 value when GeoCalc isn’t turned on in Global Mapper?

Without GeoCalc Mode enabled in Global Mapper the program will not specifically interpret or transform vertical systems. The elevation for any feature will be displayed at the Z value found in the file. 

I typically use USGS LIDAR DEM as base topography for my sites.  I update the terrain with orthodata from our drone. I typically try to clip in the updated terrain with the USGS data. Sometimes the data does not edge match very well. To get the data to match better do I need to use the GeoCalc tool to do this?

I do not think that Geographic Calculator or GeoCalc mode would be necessary unless you know your datasets reference different vertical systems. 

Often with DEM layers generated from drone collected lidar there is some level of vertical error. You can try adjusting the elevations in your layer if you know there is a particular offset, or before processing the data into an elevation model, use the QC lidar tool to rectify the point cloud to collected control points. 

In the end if the transition from one terrain dataset to another is not smooth, and there is some overlap between the datasets, consider using the feathering tool in Global Mapper to help blend the edges together. 

Which geoid grids do you have available for Europe?

The Geographic Calculator datasource does contain geoid grids for Europe. Looking at the coordinate transformation definitions you can look under vertical transformations for Europe you should see the available transformations. 


For more information on Geographic Calculator and the systems and transformations supported, download a free trial. If you’d like to try out Global Mapper and the Lidar Module, download a 14-day free trial and request a demo today

If you are interested in our upcoming webinars, or would like to register and view past webinars, check out the GeoTalks Express schedule. For more information, contact us.

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