OPeNDAP FreeForm ND Data Handler User's Guide
Using the OPeNDAP Server with Unusual Formats

This document describes the OPeNDAP FreeForm ND Data Handler, which can be used with the OPeNDAP data server. It is not a complete description of the FreeForm ND software. For that, please refer to the FreeForm ND manual.

This document contains much material originally written at the National Oceanic and Atmospheric Administration's National Environmental Satellite, Data, and Information Service, which is part of the National Geophysical Data Center in Boulder, Colorado.

This document has been updated to include information on FreeForm ND, the last release of FreeForm. FreeForm is now supported only for use with the Distributed Oceanographic Data System; see the OPeNDAP Home page for more information.

We are interested in your comments about the OPeNDAP software, and the FreeForm ND software and this document. Send them to: support@unidata.ucar.edu.

• Preface
• 0.1 Tasks Illustrated in this Guide
• 0.2 Who is this Guide for?
• 0.3 Organization of this Document
• 0.4 Conventions
• 0.5 Notices
• THANKS
• TRADEMARKS
• 1 Introduction
• 1.1 The FreeForm ND Solution
• 1.2 The FreeForm ND System
• 1.3 Installing the OPeNDAP FreeForm ND Data Handler
• Compiling the OPeNDAP FreeForm ND Data Handler
• 2 Quick Tour of the OPeNDAP FreeForm ND Data Handler
• 2.1 Getting Started Serving Data
• 2.2 Examples
• 2.2.1 Sequence Data
• 2.2.2 Array Data
• One-dimensional Arrays
• Multi-dimensional Arrays
• A Little More Complicated
• 3 Format Descriptions for Tabular Data
• 3.1 FreeForm ND Variable Types
• 3.2 FreeForm ND File Types
• 3.3 Format Description Files
• 3.4 Format Descriptions
• 3.4.1 Format Type and Title
• Format Descriptors
• 3.4.2 Variable Descriptions
• 4 Format Descriptions for Array Data
• 4.1 Array Descriptor Syntax
• 4.2 Handling Newlines
• 4.3 Examples
• 4.3.1 Tabular versus Array Descriptions
• 4.3.2 Array Manipulation
• 4.3.3 Sampling and Data Manipulation
• 5 Header Formats
• 5.1 Header Treatment in FreeForm ND
• 5.1.1 New Behavior
• 5.2 Header Types
• 5.2.1 File Headers
• 5.2.2 Record Headers
• 5.2.3 Separate Header Files
• Separate File Header
• Separate Record Headers
• 5.2.4 The dBASEfile Format
• 6 The OPeNDAP FreeForm ND Data Handler
• 6.1 Differences between FreeForm ND and the OPeNDAP FreeForm ND Data Handler
• 6.2 Data Type Conversions
• 6.2.1 Conversion Examples
• Arrays
• Collections of Variables
• Multiple Arrays
• 7 File Servers
• 7.1 The Problem
• 7.2 The OPeNDAP File Server Solution
• 7.2.1 Selectable Data
• 7.2.2 What It Looks Like
• 8 FreeForm ND Conventions
• 8.1 File Name Conventions
• 8.2 File Name Extensions
• 8.3 File Name Relationships
• 8.4 Determining Input and Output Formats
• 8.5 Locating Format Files
• 8.5.1 Search Sequence
• 8.5.2 Case Sensitivity
• 8.6 Command Line Arguments
• 8.6.1 Specifying Input and Output Files
• 8.6.2 Specifying Format Description Source
• 8.6.3 Changing Run-time Parameters
• 8.6.4 Defining Filters
• 9 Format Conversion
• 9.1 newform
• 9.2 chkform
• 9.3 readfile
• 9.4 Creating a Binary Archive
• 9.4.1 Simple ASCII to Binary Conversion
• 9.4.2 Converting to Binary
• 9.4.3 Reconverting to Native Format
• 9.4.4 Reading the Binary File
• 9.4.5 Conversion to a More Portable Binary
• 9.4.6 Converting to Binary Long
• 9.4.7 Reading the Binary File
• 9.4.8 Including a Query
• 9.5 File Names and Context
• 9.5.1 "Nonstandard" Data File Names
• 9.5.2 "Nonstandard" Format Description File Names
• 9.6 Changing ASCII Formats
• 10 Data Checking
• 10.1 Generating the Summaries
• 10.2 Example
• 10.3 Interpreting the Summaries
• 10.3.1 Processing Summary
• 10.3.2 Variable Summaries
• A HDF Utilities
• A.1 makehdf
• A.1.1 Example
• A.2 splitdat
• A.2.1 Index Creation
• Example
• A.2.2 HDF Translation
• Example
• A.3 pntshow
• A.3.1 Extracting Headers and Data
• Example
• A.3.2 Extracting Data Only
• Examples
• B Error Handling
• B.1 Error Messages
• Index
• Footnotes