DX allows you to store data in many different ways to make it easy to use the data in a DX program. As well as its built in DX format for files, it also accepts three other industry standards that are used to store scientific data.

Native File Formats:

• DX Format Files (.DX)
• DX Colormap Files (.CM)

Other File Formats:

• CDF - Common Data Format
• NetCDF - Network Common Data Form
• HDF/SDS - Hierarchical Data Format

A DX data file consists of header and body sections. The headers describe one or more DXobjects, and the data section is a text or binary representation of the data.

Sample .DX File:

# Regular Grid Example (3x3x2 box)
# Object 1 - regular grid positions
#	   - Origin at [0,0,0]
#          - Deltas are [1,1,1]
#

object 1 class gridpositions counts 3 3 2
origin	0	0	0
delta	1	0	0
delta	0	1	0
delta	0 	0	1

# Object 2 - connections betweem the grid positions

object 2 class gridconnections counts 3 3 2
attribute "element type" string "cubes"
attribute "ref" string "positions"

# Object 3 - data for the grid

object 3 class array type float rank 0 items 18 data follows
10.1	5.2	3.2	4.3	-12.2	3.4
-43.2	32.1	3.2	6.3	-5.0	3.2
9.2	-1.4	0.0	-23.1	20.1	5.2

# Creation of a field to hold the 3 objects

object "Sample DX file" class field
component "positions" value 1
component "connections" value 2
component "data" value 3

end

This DX file defines a 3x3x2 box with regular connections between its points & with data values associated with each point.

In this example object one defines a 3x3x2 set of positions that are based on a normal coordinate system, which is specified by the deltas. Object two defines the connections between the positions that were created in object one, and sets a one to one correspondence between object one and two. Object three consists of the data that is assigned to each of the points in our file. Finally all of the components are merged into one field so they can be manipulated by DX.

This DX file format is very extensive, and can represent almost any type of data because of this complexity, there are too many possible examples to present here. You are encouraged to read more about the DX data format in the User's Guide starting on page B-3.

DX colormap files are created by using the Save As... option in the File menu of the colormap editor. This file type is useful for preserving colormaps across different programs.

When CDF files are imported, unless the variable parameter is set, all fields are imported into a DX Group. Only CDF r-variables are supported by DX.

CDF Homepage at the National Space Science Data Center - This site contains all of the latest disrtibutions for the CDF Libraries, and other information relating to the CDF data format.

The netcdf files are imported similarily to the CDF files, in that all variables will be imported into a corresponding group in DX, unless the variable field is inputed in which case only those variables will be imported. Data can be both regular and irrecular, as well as scalar, vector, or tensor.

NetCDF Homepage at University Corporation for Atmospheric Research - Contains information about the netCDF data format, and has implementations in 'C', C++, Fortran, and Perl.

In the HDF files, scientific data sets are read in as fields. If there is more that one set in the HDF file, the variable will control which data is loaded. If a scale is present, it is interpereted as "positions" with regular "connections". Normally the data is imported as a regular grid with regular connections.

HDF Homepage at University of Illinois at Urbana-Champaign - Contains all of the latest information about HDF & SDS and the latest updates to the standard and libraries to implement HDF in programs.

Other soures

Import Module Tutorial
sci.data.formats newsgroup FAQ