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You are here: Advanced Job Options > Band Options > Selecting and Mapping Bands

Selecting and Mapping Bands

For raster multispectral images, you can select and map image bands from a source image to a MrSID or JPEG 2000 output image. Not all workflows are available for all output formats.

The following table shows which workflows each format supports.

 

Support for Band Selection and Mapping in GeoExpress Output File Formats
Workflow:   Supported by Output File Format:
  MG2 MG3 MG4 JPEG 2000
Choose one band from an RGB or multispectral source image to represent the single output ("grayscale") band ♦ ♦ ♦ ♦
Map any three bands from an RGB or multispectral source image to the red (R), green (G) and blue (B) output bands ♦ ♦ ♦ ♦
Choose to carry all source bands over to your output image in their original order     ♦ ♦
Map an arbitrary subset of bands (more than 3) from a multispectral image to your output image in any order     ♦  

By default, GeoExpress retains all source bands in order.

The following procedures assume you have loaded one or more images into the Job List.

Selecting a Grayscale Band

You can select a single band for MrSID or JPEG 2000 output.

  1. Select a MrSID or JPEG 2000 format from the Output Format drop-down menu.
  2. Click the Advanced button in the Properties tab.

    3. The Advanced Job Options dialog box appears.

  3. Select the Bands tab.
  4. From the Color Space drop-down menu choose Grayscale.

    5. A drop-down menu appears listing all the available bands in the source image.

  5. Choose any single band from the drop-down menu.
  6. Set other options on this tab or click OK.

Selecting Bands for RGB Output

You can select and map bands for RGB output in MG3, MG4, or JPEG 2000 format.

  1. Select a MrSID or JPEG 2000 format from the Output Format drop-down menu.
  2. Click the Advanced button in the Properties tab.

    3. The Advanced Job Options dialog box appears.

  3. Select the Bands tab.
  4. From the Color Space drop-down menu choose RGB. Several drop-down menus appear listing all the available bands in the source image.
  5. Choose any three bands from the drop-down menus.
  6. Click OK.

Retaining All Source Bands in Order

You can carry over all source bands to MG4 or JPEG 2000 output formats in their original order.

  1. Select MrSID Generation 4 or JPEG 2000 from the Output Format drop-down menu.
  2. Click the Advanced button in the Properties tab.

    3. The Advanced Job Options dialog box appears.

  3. Select the Bands tab.
  4. From the Color Space drop-down menu choose Same as source.
  5. Set other options on this tab or click OK.

Selecting and Mapping Bands for Multispectral Output

You can select and map more than three bands for MG4 output.

  1. Select MrSID Generation 4 from the Output Format drop-down menu.
  2. Click the Advanced button in the Properties tab.

    3. The Advanced Job Options dialog box appears.

  3. Select the Bands tab.
  4. From the Color Space drop-down menu choose Multispectral, then click Select Bands.

    5. The Select Bands dialog box appears. By default, all bands are carried over from the input list to the output list.

    NOTE: The Alpha band is encoded losslessly and is not displayed in the list of bands. For more information on Alpha bands in MrSID images, see Alpha Options. For more information about Alpha bands in JPEG 2000 imagery, see Encoding with Alpha Bands in JPEG 2000.

  5. If the image contains red, green, and blue (RGB) bands, re-order the bands with the up and down arrows so that these bands are at the top of the bands list, then select the option to Apply RGB Color Transform to First Three Bands.

    6. When you set the first three bands of the image as the RGB bands and apply the RGB Color Transform, GeoExpress optimizes the image compression ratio of each one of the RGB bands to create a smaller image without sacrificing visual quality.
    For more information on the RGB color transform, see The RGB Color Transform.

    This option is enabled by default for multispectral images.

  6. Optionally, select the bands that you want to remove from the output image and click the left arrow to remove them.
  7. Click OK.

NOTE: For information on setting per-band compression ratios, see Specifying Per-Band Compression Ratios.