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ENVI

Open and Display Files

Open and Display Files

Use File > Open, File > Open As, File > Data Manager, or toolbar buttons to open and display supported file types. To display data in multiple views, see Image Window Views.

See the following topics:

Open Files


To open files:

  • From the menu bar, select File > Open and browse for a file from the Open dialog.
  • From the toolbar, click the Open button.
  • From the menu bar, select File > Open As and choose a sensor or file type from the options listed. Opening files through this menu option ensures the correct metadata and ancillary files are read along with the respective image files.
  • Files that you opened recently using File > Open or File > Open As are available under File > Open Recent for easier access in the current or future ENVI sessions.
  • From the menu bar, select File > Open World Data to open the following sample data files:
    • OpenStreetMap vectors
    • Shapefiles of world airports, coastlines, countries, geographic lines, lakes, minor islands, populated places, ports, rivers, roads, and states/provinces. Data courtesy of Natural Earth. Free vector and raster map data are available at naturalearthdata.com. Select the All Vectors menu option to open all of these vector layers at once.
    • Shaded Relief: The 1:10 Natural Earth I dataset in JPEG2000 format; it includes a shaded relief raster layer with water bodies.
    • Elevation (GMTED2010): Global Multi-resolution Terrain Elevation Data 2010.
  • Georeferenced files automatically display with a North arrow if the Show North Arrow preference is set. North arrows are not displayed on geographic lookup table (GLT)-based images.
  • Windows users can drag and drop a file from ArcMap™ software, ArcCatalog™ software, or the Windows File Manager into the Image window. If multiple views are open, you can drag and drop files to a desired view in the display or to the view icon in the Layer Manager.
  • Select a file or files to open in the Open dialog. You can multi-select files by using Ctrl+click or Shift+ click.
  • If the Auto Display Files On Open preference is set to True (the default), ENVI automatically displays the true-color image, a grayscale image, an annotation layer, a vector layer, an Esri® feature class, or an Esri layer in the Image window.
  • If the Auto Display Files On Open preference is set to False, the Data Manager appears for you to select how to display the data.
  • To remove an image from the Image window, right-click on the filename in the Layer Manager and select Remove. The file remains open in the Data Manager but is not displayed in the Image window.
  • To close all files, select File > Close All from the menu bar. Files are removed from the Data Manager and Layer Manager.

ENVI uses information from the image metadata to determine how to automatically load the image. The following items assume the Auto Display Method For Multispectral Files preference is set to True Color.

  • If the image has wavelength information and bands are available for visible red, green, and blue wavelengths, they will be assigned red, green, and blue. ENVI defines true color as the smallest difference in the wavelength values closest to red as 0.64 µm, green as 0.55 µm, and blue as 0.47 µm.
  • If the image has wavelengths, but they are not in the visible region, or the image does not have wavelength information, the following rules apply:
  • If the image has three bands, ENVI assumes that they are red, green, and blue (in that order), and assigns band 1 to red, band 2 to green, and band 3 to blue.
  • If the image has four bands, ENVI assumes that they are blue, green, red, and near infrared (in that order), and assigns band 3 to red, band 2 to green, and band 1 to blue.
  • If the image has more than four bands, ENVI loads band 1 into a grayscale display.
  • If the image is in NITF format and has default bands set, default bands take precedence.
  • If the image has an associated header file with default bands set, those take precedence upon loading the image.

Open and Display Files from the Data Manager


The Data Manager lists all datasets that are open in the current ENVI session. While the Layer Manager only lists the bands that are displayed in the Image window, the Data Manager lists all available bands of a raster. If wavelengths are defined in the ENVI header file, the Data Manager shows wavelength colors next to each band. Bands with invisible wavelengths are colored black. If bad bands are defined in the header file, those bands are marked with a warning symbol.

To open files using the Data Manager:

  • From the menu bar, select File > Data Manager and click the Open button in the Data Manager toolbar browse for a file from the Open dialog.
  • From the toolbar, click the Data Manager button.
  • If the Auto Display Files On Open preference is set to True (the default), ENVI automatically displays a true-color image, a grayscale image, an annotation layer, a vector layer, an Esri® feature class, or an Esri layer based on your file type.
  • If the Auto Display Files On Open preference is set to False, select how to display the data.
  • Esri layer files display in the Layer Manager and Data Manager with the layer name (not the filename).
  • To close files, use the Close or Close All button in the Data Manager. You can also select File > Close All from the menu bar to remove all files from the Data Manager and Layer Manager.
  • Click the Pin button in the Data Manager toolbar to have the Data Manager persist on the screen as you load subsequent layers into the display. Click the button again to have the Data Manager close whenever you load layers into the display.

To manually display raster data:

  • To assign an RGB combination, expand the Band Selections category of the Data Manager. Click the band name you want to assign to red, then repeat to make the green and blue selections. Click Load Data.
  • To load a true-color image, right-click on a filename in the Data Manager and select Load True Color. The image must have wavelengths defined for this option to be available. ENVI defines true color as the smallest difference in the wavelength values closest to red as 0.64 µm, green as 0.55 µm, and blue as 0.47 µm.
  • To load a color-infrared (CIR) image, right-click on a filename in the Data Manager and select Load CIR. The image must have wavelengths defined for this option to be available. ENVI defines color infrared as the smallest difference in the wavelength values closest to near-infrared as 0.86 µm, red as 0.65 µm, and green as 0.55 µm.
  • To load a grayscale image, select a band and click the Load Grayscale button.
  • Right-click on a filename and select Load Default to display an image that has assigned default bands in the associated ENVI header. If you do not define default bands to load but the image file contains wavelength information, Load Default uses the default setting in the Auto Display Method For Multispectral Files preference.
  • You can drag-and-drop individual bands from the Data Manager to multiple views.
  • You can drag-and-drop a multispectral filename from the Data Manager to a view to display an RGB image in that view.
  • To open a file in a new view, enable the Load in New View check box, right-click on a filename, and select from one of the Load options.

To manually display other data types:

  • To load an ROI, right-click on the ROI name and select Load ROI, or select multiple ROIs, right-click, and select Load Files. You can also click and drag one or more ROIs from the Data Manager to the raster to associate it with in the Layer Manager. If the raster already has associated ROIs, you can click and drag to the Regions of Interest folder under the raster layer.
  • For NITF files with multiple image segments: each NITF segment appears in that group as a separate layer. NITF files with multiple image segments appear as subfolders under the NITF file. An image segment name consists of a base filename followed by its image identification (IID). The image segment name is then followed by the security level of the image segment (if it is not Unclassified). This is followed by the band name, which includes the word Band and the index number (except in the case of a single-band image).
  • For vector shapefiles that are stored in the CSSHPA Data Extension Segment (DES), right-click on a vector name in the Data Manager and select Load Vector.
  • To display Esri® layer source data, expand the Esri layer, select the data source, and load the source data. Layer files in ArcGIS® software consist of a set of rules for displaying and working with datasets. Information in files can include symbols, classifications, labeling rules, and other information describing the appearance and actions of the layer. When visualizing an Esri layer, ENVI inherits properties from ArcGIS. If you open the source data for an Esri layer, you will be using ENVI properties (e.g. stretch) and the two may not display the same way.
  • You can load multiple Esri layers with the same filename into the Data Manager.

    Note: Layer files reference data sources; they do not include the actual data. If referenced data in a file is renamed or moved, the layer files must be updated in ArcMap software or ArcCatalog software to use the new path. For more information on files and data sources, see the ArcGIS Help.

Special Cases for NITF Files

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.
  • If a NITF file contains a lookup table and mask, the software ignores the lookup table and uses the mask.

File Type Icons

The different file types are indicated by icons that appear next to the filename in the Data Manager. The icons are as follows:

Multispectral dataset Multispectral file

Grayscale image Grayscale file

Classification image Classification file

NITF file

Esri raster, point, or line and polygon file

Annotation file

Point file

Polyline file

Polygon file

ROI file

File Information

The File Information category of the Data Manager provides detailed information about a file. This category is collapsed by default. You can expand or collapse this category by clicking the arrow next to the category name. When expanded, the File Information category lists information derived from the file header.

You cannot edit the File Information fields in the Data Manager. To edit header information, see ENVI Header Files.

Raster Layer Information

  • File: Filename, including the full path.
  • Dims: File dimensions, including number of rows, columns, and bands; and interleave (BIL, BIP, or BSQ).
  • Data Type: Data type (unsigned integer, byte, etc.)
  • Size: File size in bytes. This information is available for all datasets except for WCS, WMS, and JPIP remote datasets.
  • File Type: File format.
  • Wavelength: Wavelength range, if wavelength information is available.
  • Projection: Projection name (for georeferenced images), including datum and pixel size. If the file contains rational polynomial coefficient (RPC) information, the text *RPC* precedes the projection type.
  • Upper Left Corner: Image coordinates for the upper-left pixel in the image for images with XSTART and YSTART values (extracted from the ENVI header). If your image is a spatial subset of a larger image, the image coordinate system references the parent (or larger) image.

Vector Layer Information

  • File: Filename, including the full path.
  • Shape Type: Type of vector record (Point, Polyline, Polygon).
  • Number of Records: Number of vector records in the file.
  • Number of Vertices: Number of vertices in the file.
  • Number of Quad-Tree Nodes: Number of quadtree nodes created.
  • File Size: File size, in bytes.
  • Attributes: Indicates whether or not an attribute table exists for this layer.
  • Projection: Projection name (for georeferenced data), including datum and measurement units.

Annotation Layer Information

  • File: Filename, including the full path.
  • Number of Annotation Items: Number of annotation items in the file.
  • Number of Quad-Tree Nodes: Number of quadtree nodes created. Annotations currently use only one node.
  • Projection: Projection measurement units.

Esri Layer Information

  • File: Filename, including the full path.
  • Data Name: Esri layer name (name displayed in the ArcMap Table of Contents).
  • Layer Type: Feature Layer or Raster Layer
  • Shape Type (for Esri feature classes only): Type of vector record (Point, Polyline, Polygon).
  • Data Type (for Esri raster layers only): Data type (unsigned integer, byte, etc.)
  • Dims: File dimensions, including number of lines, samples, and bands; and interleave (BIL, BIP, or BSQ).
  • Top/Bottom/Left/Right: The left, top, right, bottom coordinates of the raster dataset.
  • Projection: Projection name (for georeferenced data), including datum and measurement units.

ROI Layer Information (for .roi files)

  • Region Name: Region of interest name.
  • Number of Elements: The number of elements, which is 1.
  • Name: Region name from ENVI Classic.
  • Dims: File dimensions as samples and lines.
  • Npts: The number of image pixels for this ROI.



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