Transformation from Lambert72 to Lambert 2008 in ArcGIS Pro and ArcGIS Enterprise

August 25, 2026 | Romain Kahn & Miriam Baudewyn

The Belgian Lambert 2008 projection system (EPSG: 3812) is based on the ETRS89 geodetic reference system. Compared with the older Lambert 72 projection system, Lambert 2008 provides better integration with European and cross-border geographic data.

For projects in Belgium, the Belgian Lambert 2008 is recommended as the standard map projection. This is in line with current national and European standards and is compatible with GNSS measurements. If you are working with datasets that were created using Lambert 72, accurate transformation methods are available. 

Two transformation methods are integrated by default in ArcGIS software. These are a basic Helmert-type transformation with an accuracy of 1 m (EPSG :1652) and a more refined 7-parameter Helmert transformation with an accuracy of 0,2 m (EPSG : 15748). 

The Belgian National Geographical Institute (NGI) provides an NTv2 transformation grid. In addition to using a 7-parameter Helmert transformation, the NTv2 grid transformation first employs a correction grid to compensate for distortions that arose during the development of the Lambert 1972 system, thereby providing an accuracy of approximately 1 cm.

In ArcGIS, this NTv2 transformation is not integrated by default, but is available through the ArcGIS Coordinate Systems Data module. In this article we will discuss how to use this most accurate transformation in ArcGIS Pro and on ArcGIS Enterprise / ArcGIS Server.

The NTv2 transformation grid has been integrated by ESRI with every version of ArcGIS software. However, they are not included with the default software. Grid files are compact, but including NTv2 grids for every country would make ArcGIS Pro too large. That’s why NTv2 grids are available as a separate, easy-to-install package, the “ArcGIS Coordinate Systems Data” module. 

To find this module, you must go to My Esri. You can find this module under the download tab. The “ArcGIS Coordinate System Data” module is to be downloaded from the ArcGIS Pro related modules, under “Data and Content”. Make sure that you download the version corresponding to your ArcGIS Pro version.

Note: when upgrading ArcGIS Pro, a new version of ArcGIS Coordinate Systems Data must be installed, corresponding to the new ArcGIS Pro version

You need to consider the installation type of ArcGIS Pro (determined by the installation settings, see https://pro.arcgis.com/pro-app/get-started/arcgis-pro-installation- administration.htm). 

If it’s a “per user” installation (this is the default installation option, parameter ALLUSERS = 2), you will need to install the “ArcGIS Coordinate Systems Data for ArcGIS Pro Per User Install” module.

If it’s a “per machine” installation (parameter ALLUSERS = 1), the “ArcGIS Coordinate Systems Data” module must be installed.

If you do not need all transformations, you can choose to install part of the contents of this module during the installation process. To do so, click on the icon next to the specific component:

After installation, the NTv2 transformation from the Belgian 72 Datum to the ETRS89 Datum is available under the name “Belge_1972_To_ETRS_1989_3”.

Below an example in ArcGIS Pro:

When a map is published, the specifications of the used transformations are stored with the map service. However, the transformation grid itself must be available to the server when the transformation is performed on the server side. If the required grid files are not available on ArcGIS Server, ArcGIS Server will automatically use a less accurate transformation.

For this reason, you need to install the ArcGIS Coordinate System Data module on the ArcGIS Server machine. 

Note: For ArcGIS Online, the required grid files are always accessible, so no  additional installation of configuration is required.

To find this module, you must go to My Esri. You can find this module under the download tab. The “ArcGIS Coordinate System Data” module is to be downloaded from the ArcGIS Enterprise related modules, under “Data and Content”. Make sure that you download the version corresponding to your ArcGIS Enterprise version.

Install ArcGIS Coordinate Systems Data on the ArcGIS Server machine. The transformation files must be placed in the C:\Program Files (x86)\ArcGIS\CoordinateSystemsData\pedata directory. 

For the Belgian Lambert 72 → Lambert 2008 NTv2 transformation, the required grid is named BD72LB72_ETRS89LB08.gsb.The expected directory structure is: C:\Program Files(x86)\ArcGIS\CoordinateSystemsData\pedata\geographic\europe\belgium\ntv2\ with the .gsb file located in that directory.

If the ArcGIS Server site contains multiple machines, the Coordinate Systems Data module must be installed on every machine in the site.

When upgrading ArcGIS Enterprise, the previous version of ArcGIS Coordinate Systems Data must be uninstalled before installing the new version. We therefore recommend including the Coordinate Systems Data installation and the verification of the required NTv2 grid as part of the ArcGIS Enterprise upgrade procedure. 

If you have any questions about this topic or need help with the transformation from Lambert72 to Lambert 2008, please feel free to contact info@esribelux.com.