Graphics > Graphics Gallery > Images > Binary Image Data

# Binary Image Data

## Display Binary Data

If your image data is in a nonstandard image format, you can use the READ_BINARY routine to read binary information from the file.

### Example 1 - Binary Data

The following example reads byte data out of the file `nyny.dat` in IDL's examples/data subdirectory into an IDL variable named `nyny`.

The code shown below creates the graphic shown above. You can copy the entire block and paste it into the IDL command line to run it.

file = FILEPATH('nyny.dat', $

SUBDIRECTORY = ['examples', 'data'])

nyny = READ_BINARY(file, DATA_DIMS = [768, 512])

; Display the image using the IMAGE function

im = IMAGE(nyny, RGB_TABLE=36)

### Example 2 - Regular-Grid Data

Regular-grid data points are presented by two-dimensional arrays. The following example shows one way of importing and displaying this type of data. The 248-by-248 two-dimensional array contained within the `convec.dat` binary file in the `examples/data` directory is imported into IDL with the READ_BINARY function. The image function then displays this data as an image.

The code shown below creates the graphic shown above. You can copy the entire block and paste it into the IDL command line to run it.

; Define the data

file = FILEPATH('convec.dat', $

SUBDIRECTORY = ['examples', 'data'])

; Use READ_BINARY to specify data dimensions

data = READ_BINARY(file, DATA_DIMS = [248, 248])

; Use the IMAGE function to display the data

IM = IMAGE(data)

### Example 3 - Assign an RGB Table

This example uses the surface.dat example data, which is elevation data from the Maroon Bells mountain range in Colorado, USA. This data is stored as integer data in a binary file.

The code shown below creates the graphic shown above. You can copy the entire block and paste it into the IDL command line to run it.

; Define the data.

file = FILEPATH('surface.dat', $

SUBDIRECTORY = ['examples', 'data'])

; Use READ_BINARY to specify data dimensions

mbells = READ_BINARY(file, DATA_DIMS = [350, 450])

; Use the IMAGE function to display the data

IM = IMAGE(mbells, rgb_table=6)

## Property Used in the Example

- `RGB_TABLE` - defines the color table used to display the image. If no color table is defined, this image displays in gray scale.

## Resources

- Changing graphics properties
- Multiple graphics in one window
- Save a graphic
- IMAGE
- READ_BINARY
- IDL Graphics Functions
- Formatting IDL Graphics Symbols and Lines