This topic describes how to open and display NITF and MIE4NITF files and view their metadata, Also described is how to use the NITF Dataset Browser, including how to animate NITF files with multiple image segments and MIE4NITF files with multiple series of image frames.

A NITF Module license is required to open these data formats; contact your sales representative for more information.

See the following sections:

Open NITF Files

To open a NITF dataset, select File > Open from the ENVI menu bar and select a .ntf, .nitf, .nsf, or .r0 file. If only one displayable image segment is included in the dataset, ENVI will display it in the view and add it to the Layer Manager and Data Manager. If the NITF dataset has multiple image segments and more than one can be displayed, ENVI will open the NITF Dataset Browser where you can choose which image segment(s) to display.

To view the metadata for a NITF dataset, right-click on the NITF layer in the Layer Manager or Data Manager and select View NITF Metadata. The NITF Dataset Browser appears with the metadata listed in the right-side panel.

The contents of the image representation (IREP) and band representation (IREPBAND) fields in the image subheader affect how NITF images display. The IREP values that occur most frequently are MONO (monochrome), RGB (three-band true color), RGB\LUT (single-band image with color palette), MULTI (multi-band imagery), and NODISPLY (image not intended for display). The IREPBAND values used in this process are R (Red), G (Green), B (Blue), M (Mono), and LU (Look-Up Table). The image contains one IREP value for the image segment, and one IREPBAND value for each band in the dataset.

  • Images with the IREP value RGB\LUT will be displayed in true color by default, and the image will be decomposed into red, green, and blue bands.
  • Multiple-band images with three bands identified as R, G, and B are displayed as RGB composites, and the three bands will be represented as red, green, and blue bands.
  • If no RGB values are found in the image, and there is a band marked LU, this band will be displayed with the lookup table applied. If the image contains a band with the value M, it is displayed as a grayscale image.

Open MIE4NITF Files

MIE4NITF datasets are NITF files that organize groups of image segments into "cameras" that represent time-lapsed motion. They can also contain standard NITF image segments. MIE4NITF files always open into the NITF Dataset Browser, which is described in the next section.

To open a MIE4NITF file, select File > Open from the ENVI menu bar and select a .ntf, .nitf, .nsf, or .r0 file. If you select the manifest file (.ntf), all cameras and image segments from the NITF files that make up the dataset are loaded into the NITF Dataset Browser. Alternatively, if you select a MIE4NITF file containing the frame data itself, only the frames and related segments from that file will be loaded into the NITF Dataset Browser.

A MIE4NITF dataset consists of one or more NITF files stored in the same directory. If the MIE4NITF dataset consists of more than one file, one of them will be a manifest file, which is easiest to identify based on its small file size (typically less than 1 MB). The manifest file is used as an index for how the camera frames are dispersed across the NITF files that make up the MIE4NITF dataset.

NITF Dataset Browser

The NITF Dataset Browser manages large NITF and MIE4NITF files with many image segments and series. You can view the contents of multiple files and view the metadata for selected files, segments, and series. The browser appears when you open a MIE4NITF dataset, or when you open a NITF file with more than one displayable image segment. You can also open the browser by clicking the NITF Browser button in the ENVI toolbar.

In the example below for a NITF file, the left panel of the browser lists the segments of the opened NITF file. These include image segments, security segments, text segments, Tagged Record Extensions (TREs), and Data Extension Segments (DESes). The right panel of the browser displays the security banner for the NITF file and the metadata for the selected segment.

The example below is of a MIE4NITF file. The left panel of the browser lists all of the camera frame collections, plus any standalone image segments. A MIE4NITF file can contain one or more cameras, each of which can be opened in ENVI as a raster series.

Tips for using the browser:

  • To open additional NITF or MIE4NITF files in the browser, click the Open button in the browser toolbar and select the files to open.
  • To collapse/expand the contents of all datasets at once, click the Collapse or Expand button in the browser toolbar.
  • To close one or more datasets, select the datasets and click the Close or Close All button in the browser toolbar.
  • To load image segments or series to the Data Manager, select one or more of them (using Ctrl-click) and click the Load to Data Manager button in the browser toolbar. Or, right-click on the selected items and select Load.
  • To display image segments or series in the ENVI view, select one or more of them (using Ctrl-click) and click the Display in View button in the browser toolbar. Or, right-click on the selected items and select Display.
  • To load and/or display a NITF file with multiple image segments, right-click on the filename and select Load Dataset as a Multiseg or Display Dataset as a Multiseg. The latter option will display all of the image segments that make up the multi-segment file.
  • To copy metadata to the clipboard, click the Copy Text button on the right side of the browser toolbar, then paste the text into an application of your choice.
  • To save metadata to a text file, select the filename and click the Save Metadata button in the upper-right corner of the NITF Dataset Browser. Select an output location and filename for the text file, then click Save.
  • To save DES data to a file, expand the DES tree in the left side of the browser, right-click User Defined Data, and select Save As.
  • To view or save metadata for an "associated file" in a MIE4NITF dataset, open the associated file directly in the NITF Dataset Browser.
  • If you encounter display issues with the NITF Dataset Browser on Linux platforms, try setting the NITF Browser Display preference to Plain Text.

Additional tips for working with MIE4NITF datasets:

You can load and display individual frames within a series as standalone rasters into ENVI. Select one or more frames in the browser and click the Load to Data Manager or Display in View button in the browser toolbar. ENVI treats the frames as individual rasters.

You can choose to load or display a subset of a series before loading it into the Data Manager or displaying it in the ENVI view. This helps to quickly identify content of interest without having to load the entire MIE4NITF dataset. Use the following steps:

  1. Select a series in the NITF Dataset Browser and click the Subset Camera Frames button in the browser toolbar. Or, right-click on the selected series and choose Subset. The Camera Frame Selection dialog appears.
  2. Enter the frame numbers to subset in the Start Frame and End Frame fields.
  3. Enter an Increment value to skip a certain number of frames. For example, a value of 5 will only include every fifth frame in the subset.
  4. Enable the Display result check box to display the subset in the ENVI view.
  5. Click OK.

Animate Datasets

You can select series, frames, or image segments from the NITF Dataset Browser to animate in the Xtreme Viewer or in the Series Manager.

To animate a MIE4NITF series or NITF image segments in the Xtreme Viewer:

  • For a MIE4NITF series: Select a series in the browser, then click the Play in Xtreme Viewer button on the toolbar Or, right-click a series and select Play in Xtreme Viewer.

  • For NITF image segments: Right-click to select an image segment to use as the baseline image segment and select Animate Similar > Using Xtreme Viewer.

    See Animate Using Xtreme Viewer for details.

To animate MIE4NITF series and frames, or NITF image segments in the Series Manager:

  • For MIE4NITF: Right-click a series and select Display to open it into ENVI. When the series opens in ENVI, the Series Manager appears.
  • For MIE4NITF: Right-click a series and select Subset to specify frames to load into ENVI as a series. When the series opens in ENVI, the Series Manager appears.
  • For NITF: Right-click an image segment to select it as the baseline image segment, and select Animate Similar > Using Raster Series.ENVI combines image segments that have IDs similar to the baseline into a series. When the series opens in ENVI, the Series Manager appears.

    See Animate Raster Series and NITF Image Segments for details.

See Also

NITF Background, NITF Tagged Record Extensions Background, NITF PIA TREs Background, Save NITF Files, ENVINITF Routine