GEF-CPT - A standard exchange format for CPT's

GEF (Geotechnical Exchange Format) is a general language structure for storing and transferring geotechnical information. GEF states in a procedural way how a new structure (a set of rules for the storage of measurements) should be composed. This report provides a basis for a general exchange of digital cone penetration test data. Existing formats are specifically directed at a client and are therefore not unambiguous and exchangeable. In cases where there are large quantities of penetration test data delivered in a variety of formats, this not only leads to communication problems but also to delays and increased costs.

GEF and GEF-CPT-Report

There is a distinct difference between GEF and e.g. GEF-CPT-Report. GEF is a method for the exchange of data of an arbitrary test on soil. More info on GEF itself can be found on the GEF-Language page.
GEF-CPT-Report is a way to exchange data of precisely one, very specific test on soil, i.e. data obtained during a Cone Penetration Test (CPT).


The new format, which is described in the GEF-CPT-REPORT document shows a number of advantages:


Example of a visualisation of a CPT,
with pore pressure u2, fricton and friction number

Example of a CPT with pore pressure u2, fricton and friction number. The graph has been made using the programm "GEFPlottool". For more info about this programm, visit the website of Delft Geosystems

Viewer and GEF Verification

In order to view the CPT-results graphically, you can use the GEF-CPT-viewer software. The cone resistance, sleeve friction, friction ratio and pore water pressure (u2) are displayed in conformity with the NEN 5140 standard (however mind the paper format!)

Visualisation of the same CPT as above, made by the 
programm 'GEF verification'

GEF-Verification is part of the GEF-viewer. It can be used to verify whether files comply with the GEF-CPT-Report format. Verification consists of checking for syntax errors and contextual inconsistencies in digital CPT-files using the GEF-CPT-Report format. The software opens a GEF-file and performs a verification. A log of the errors that are found is given. Verification of GEF-files in batches is also possible.
In September 2002 the program has been updated, version: 1,1,0,0. It is now compatible with GEF-CPT-Report 1,1,0. Read readme.txt for installation. Download the program (340kB, 2003-05-23).

GEF Library

NENGEO conversion tool

The NENGEO-format has been used since years as a standard format for CPT's in the Netherlands. If you are running Windows-XP, it is possible to convert a file in the NENGEO-format to GEF-format and vice versa by means of the GEF-NENGEO-converion tool.

The conversion tool has been written in Java. In order to run the tool, you must install SUNs© java runtime engine; you can download it via SUN©s website. On the SUN© website you must choose 'Windows Off line' (situation: November 2006). First of all: DO read the installation instructions. Alternatively you can download SUN©s file jre-1_5_0_08-windows-i586-p.exe. Note: you must login on your PC as a (local) administrator in order to install the java runtime engine on your PC.

GEF-CPT-Report to Excel

An Excel conversion tool to import data of a GEF-CPT-Report file into an Excel spreadsheet can be downloaded (77kB, 2000-12-14)


The full documentation of GEF-CPT-Report and many other standards can be found in the public table of standards.

GEF-CPT-Report helpdesk

Any questions or comments you might have, can be adressed electronically to the helpdesk of GEF.

GEF community

The latest news on GEF-CPT-Report can be found on this website via News and information.

Further information

Got interested for any new national standards? Phone or mail ing. A. Jonker of the CUR (telephone +31 182 540630 or e-mail A. Jonker).


CUR and all contributors to the software on have taken every possible care during the preparation and release of the software. However, it can not be guaranteed that this software is complete and/or free of faults. The use of this software and the responsibility of the results by using this software is entirely for the user's own risk and CUR hereby excludes any and all liability for any and all damage which may result from the use of this software or data based on the use of this software, except insofar as this damage is a result of intentional fault or gross negligence of CUR and/or the contributors.

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