layout: default title: fixarray parent: Grid Tools nav_order: 33 —

fixarray

Description

fixarray is a command-line utility for converting legacy JHC grid files into the modern, standardized “OMG1” JHC grid format. The tool reads the header information from an old-format binary array, creates a new standard 1024-byte JHC header, and combines it with the original data into a new, compliant file.

This tool is primarily used for data archeology to ensure backward compatibility with older datasets.

Usage 

fixarray [-really_old] <-8bit | -float> <badfile> <goodfile>

Arguments

Option Description
<badfile> Required. The path to the input legacy JHC-format grid file.
<goodfile> Required. The path for the new, corrected, standard-format JHC grid file.
-8bit Required (or -float). Specifies that the data type of the input file is 8-bit character.
-float Required (or -8bit). Specifies that the data type of the input file is 32-bit float.
-really_old A flag indicating the input file is from a very old format that is missing the ystep (Y pixel size) field in its header. If this is set, the tool assumes ystep is equal to xstep.
-v Enable verbose output.

How It Works

  1. File Opening: Opens the input legacy grid file (badfile) for reading and the new output grid file (goodfile) for writing.
  2. Header Reading (Legacy): Reads the old-format header from badfile. The structure of this old header is assumed to be known (e.g., 20 bytes for integer dimensions and bounds, then 16 bytes for float bounds).
  3. New Header Creation: A new JHC_header (good_head) is initialized with standard values. Relevant information (dimensions, bounds) is transferred from the old header to the good_head.
    • If -really_old is specified, ystep is explicitly set equal to xstep.
    • data_type is set based on -8bit or -float flags.
  4. Data Copying: The tool reads the raw pixel data directly from badfile (skipping the old header) and writes it to goodfile after the good_head. This effectively wraps the old data with a new, compliant header.

Output Files

  • <goodfile>: A new JHC-format grid file with a standard 1024-byte header.

Dependencies

  • array.h: For JHC_header structure.
  • support.h: For general utility functions and error handling.

Notes

This tool is specifically designed to handle older, non-standard JHC grid formats and migrate them to the current standard. This ensures that legacy data can be properly read and processed by modern tools that expect the current JHC_header structure. Without this tool, older files might be unreadable or misinterpreted.