| 4.0 |
Models, Conventions, and Formats
Data models, conventions, and formats are at different levels of abstraction. |
| 4.1 |
NetCDF Data Models
NetCDF supports two data models: classic and enhanced. |
| 4.2 |
NetCDF Files
NetCDF files are containers for Dimensions, Variables, and Global Attributes. |
| 4.3 |
Dimensions
Dimensions are used to specify variable shapes, common grids, and coordinate systems. |
| 4.4 |
Variables
Variables hold data values. In the classic netCDF data model, a variable can hold a multidimensional array of values of the same type. |
| 4.5 |
Variable Methods
Things you can do with a netCDF variable include getting information about it, putting data values into it, and getting data values out of it. |
| 4.6 |
Attributes
Attributes hold metadata (data about data). An attribute contains information about properties of a variable or dataset. |
| 4.7 |
Attribute Methods
Things you can do with a netCDF attribute include inquiring about its type or length, defining its value, and getting its value. |
| 4.8 |
The "Classic" NetCDF Data Model
The classic netCDF data model uses dimensions, variables, and attributes, to capture the meaning of array-oriented scientific data. |
| 4.9 |
Introducing CDL (Common Data Language)
CDL (Common Data Language) is text notation for netCDF objects and data. It will be used for examples during the workshop. |
| 4.10 |
Another Simple Example
In this example, a simple data file is examined with ncdump, showing its dimensions, variables, and attributes as CDL. |
| 4.11 |
A Convention for Coordinates: Coordinate Variables
Coordinate Variables contain the coordinate values for a dimension. |
| 4.12 |
An Example of Coordinate Variables
A concrete example of simple coordinate variables. |
| 4.13 |
Variables Versus Attributes
When should you use variables or attributes? |
| 4.14 |
Classic NetCDF Model Limitations
The classic netCDF data model used for netCDF-3 has some limitations. |
| 4.15 |
The NetCDF-4 Data Model
The netCDF-4 data model adds Groups and User-Defined Types to the classic netCDF data model, but backward compatibility is preserved. |
| 4.16 |
When to Use the Enhanced Data Model
The enhanced data model offers rich features, but breaks backward compatibility. |