This topic describes how to open and display NITF and MIE4NITF files, as well as how to view their metadata. An ENVI NITF/NSIF Module license is required to open these data formats. The NITF Dataset Browser can be used to browse and display NITF files with multiple image segments, as well as MIE4NITF files with multiple series of image frames.

NITF


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 opens the NITF Dataset Browser so that you can choose which image segment(s) to display. See the NITF Dataset Browser section below.

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 starts and lists the metadata on its right side.

Details on Displaying NITF Datasets

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.

MIE4NITF


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.

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. It 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 comprise the MIE4NITF dataset.

MIE4NITF files will always open into the NITF Dataset Browser. There, you can choose to open the frames of these cameras into ENVI as a raster series to animate as well as to open individual frames as standalone rasters. The NITF Dataset Browser will also let you load or display a subset of a camera's frames by specifying a start frame, end frame, and frame increment.

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 comprise 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 particular file will be loaded into the NITF Dataset Browser.

NITF Dataset Browser


The NITF Dataset Browser was designed to manage 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 NITF Dataset 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 it by clicking the button in the ENVI toolbar.

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

For MIE4NITF files, the left side of the browser lists all of the camera frame collections as well as 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.

Here are some general tips for using the browser:

  • To open additional NITF or MIE4NITF files, click the Open button in the browser toolbar and select the files.
  • To collapse or 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 comprise the multi-segment file.
  • To copy metadata to your system clipboard, click the Copy Text button on the upper-right side of the browser. 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 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.

Tips for Working with MIE4NITF Datasets

  • When you load a series to the Data Manager or display a series in the view, ENVI takes a few moments to build a raster series. You can use the Series Manager to animate a raster series.
  • You can also load and display individual frames that comprise a series. 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 frames as individual rasters.
  • You can choose to only load or display a subset of a series before loading it to the Data Manager or displaying it. This is useful to more quickly identify content of interest without having to load the entire MIE4NITF dataset. Follow these steps:
    1. Select a series in the 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 option to display the subsetted series after it is created.
    5. Click OK.

See Also


To learn more about the structure of NITF files, see the following topics:

To learn more about saving files to NITF format and editing NITF metadata, see Save NITF Files.

ENVI programmers can use the ENVINITF routine to manage NITF and MIE4NITF data.