Introduction

This paper describes the file format used by the SPRScan (Ground Penetrating Radar) from ERA Ltd for data storage. This format, based on the recommended standard SEG-2 format of the Society of Exploration Geophysicist (http://www.seg.org/), uses some extensions specific to the SPRScan radar.

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Abstract

File structure

The file consists of a File Descriptor Block, one or more Trace Descriptor Blocks and one or more Data Blocks. In the SPRscan context a Trace corresponds to the data recorded for a single A-scan (single point measurement in the z direction) and may contain either 256 or 512 integers. A single SPRscan data file may contain a maximum of 16'383 traces (about 17 Mbytes).

Pointers are used to indicate locations of blocks with respect to the beginning of the file. The pointers are always unsigned long integers (32 bits).

FILE DESCRIPTOR BLOCK

TRACE DESCRIPTOR BLOCK 1

DATA BLOCK 1

TRACE DESCRIPTOR BLOCK 2

DATA BLOCK 2

...

TRACE DESCRIPTOR BLOCK N

DATA BLOCK N

Block structures

File Descriptor Block

The first block in the file is the File Descriptor Block. This block holds information about structure and interpretation of the file and data common to all traces in the file.

Trace Descriptor Block

There is a one to one correspondance between Data Blocks and the Trace Descriptor Block that describes the Data Block. The file must contain at least one Trace Descriptor Block and matching Data Block.

Data Block

A data Block follows each Trace Descriptor Block. Each Data Block is a collection of numbers of the size and in the format specified in the preceding Trace Descriptor Block.