User's Manual

GPR4 Concrete Scanner

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User Manual

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Earth Science Systems, LLC

February

2019

Page 27 of 28

6.9 Data File Format

Data recorded by the GPR system are stored using the HDF5 file format. HDF5 allows

storage of large datasets in complex data structures. In addition to the data stored in an HDF5

file, the files provide all of the data type and format information needed for reading the data. A

helpful utility for quickly browsing HDF5 file is the HDFView utility which is freely available from

the HDF5 Group (https://www.hdfgroup.org/downloads/index.html). The HDF5 Group provides

free software interfaces for HDF5 in most popular computer languages including Fortran, C,

Java, Python, and Matlab. Figure A3 is a screenshot from HDFView showing the contents of an

H5 file recorded by the sonic logging system. On the left is a tree structure that lists the

datasets in the file. The JobInformation dataset contains information about the jobsite. There is

a folder for each data server (e.g., gpr4, odometer, irTemperature, pavementDensity, etc.) on

each node (e.g., the logger or the probe), and each folder contains configuration information

and data. As shown below, the detailed format of each dataset is included in the file. This self-

describing feature of HDF5 files along with the open software interfaces allows the data to be

easily read by user-developed software.

Figure A3. Screenshot from HDFView showing the contents of an H5 file recorded by the

sonic logging system.