Display Output Options

ENVI Image displays, plots, or vector windows can be saved to postscript files, image files, or directly to printers. All overlays (annotation, grid lines, vectors, etc.) can be included in (burned into) the output.

Postscript File

Image Files: ENVI file (RGB binary image with an ASCII header file), BMP, HDF, JPEG, JPEG2000, PICT, PNG (Portable Network Graphics), SRF (Sun Raster File), TIFF (including GeoTIFF and TIFF World files [.tfw]), XWD (X-Windows Dump) Image Files, ERDAS (.lan), ER Mapper, PCI (.pix), and ArcView (.bil) Files

Directly to a system printer.

Saving to Postscript Files

Use ENVI's postscript output to scale an image, burn in graphic overlays, to output an encapsulated postscript file, and to select from other output options.

To output a displayed image to a postscript file, select File

Save Image As

Postscript File from the Image window menu bar. The Output Display to Postscript File dialog appears, where you may modify the output of images, plots, and vectors. The output page is shown schematically as a draw window in the upper-right hand corner of the dialog. See the following subsections for setting the output display parameters in the dialog.

To output a plot or vector window to a postscript file, select File

Save Plot As

Postscript in the plot or vector window.

Setting Page Size and Image Scaling

Set output page sizes and image placement in either inches or cm, as specified in the envi.cfg file. Precision scaling and multiple page output is available when outputting to postscript. Any ENVI image can be scaled to a specific map scale-the image size values change automatically based on the image pixel size. If the resulting image is larger than a single page as defined in the Page text box, ENVI automatically determines the number of pages required to output the image and shows the pages in the draw window in the upper-right hand corner of the dialog. Multiple page images cannot be repositioned with respect to the page layout specified by ENVI.

In the Output Display to Postscript File dialog, set the page size by entering the desired dimensions in the text boxes labeled Page.

Set the output image size on the page by entering the desired values into the xsize and ysize labeled text boxes.

Note
To maintain the relative aspect between X and Y when one dimension is changed, select the Aspect check box.

Set the position of the image origin on the page (with respect to the lower left corner) using the xoff and yoff parameters. An outline of the image showing its relative size and position on the page appears within the draw window in the upper-right of the dialog.

To position the image on the output page using your mouse, click and hold the left mouse button inside the image outline in the draw window and drag the image to a new position.

To center the image outline on the page using your mouse, click the right mouse button anywhere on the output page.

Click on the arrow toggle button to select Landscape or Portrait as the page orientation.

Select from the following options.

To scale an image to a specified map scale, enter the desired scale in the Map Scale 1: text box. The xsize and ysize values will change automatically based on the image pixel size (a default size of 30 meters is assumed if no pixel size is present in the header).

To toggle color on or off, select or de-select the Color check box.

To select encapsulated postscript output, select the Encapsulate check box.

To select the number of output bits for the postscript image use the Bits pull-down menu.

Setting Graphics Overlay Options

Graphics options (annotations, grid lines, regions of interest, vectors, etc.) can be permanently incorporated in the saved PostScript file. All currently displayed valid ENVI graphics objects are automatically selected when the Output to PostScript File dialog is started. A border is automatically placed on the output image if grid lines are selected. The grid text-labels are placed exterior to the image.

In the Output Display to Postscript File dialog, click Change Graphic Overlay Selections. The Change Graphics Overlay Options dialog appears with a list of the currently displayed graphics objects.

Change the graphic overlay selections using the following options:

To remove a graphics overlay, click on its name in the Currently Selected Options list.

To add graphics overlays, select the desired overlay using the Add Graphics Option pull-down menu (with the exception of annotation, these overlays must be displayed on your image or plot).

To add an annotation file that is not currently displayed to the graphics overlay, select Additional Annotation File from the Add Graphics Option pull-down menu and select the desired annotation filename.

Click OK to return to the Output to Postscript File dialog.

Note
To clip all graphics at the edge of the page when multiple pages of output are generated, select the Clip Graphics check box.

Subsetting and Resizing Output Images

To select a spatial subset of the output image, click Spatial Subset. For subsetting details, see Selecting a Spatial Subset.

To resize the image, enter a resize factor (less than 1 for subsampling) in the Input Image Resize Factor text box.

Applying Masks

In the Output Display to Postscript File dialog, you have the option of applying a predefined mask to your output image. This means that if you want to apply a mask to the image, you do not need to do it before selecting the output options.

In the Output Display to Postscript File dialog, click Select Mask.

Select the input band for the mask.

In the Background R, G, and B boxes, enter desired color values that you want to use where the mask is turned off.

Click OK.

Note
To clear the selected mask and output a complete image, click Clear Mask.

Saving Output Files

Enter the output filename or use the Choose button to select the output filename.

Click OK when all options are correctly set.

If the parameters you have chosen result in multiple page output, the filename is used as a root filename, and numbers designating the position of the multiple pages in the composite image are appended to the filename. For example, an image with 6 pages (3 columns by 2 rows), using the file root name test creates the output files test_11, test_12, test_21, test_22, test_31, and test_32, where the first appended number indicates the column, and the second appended number indicates the row.

Saving to Image Files

ENVI has many image output options for the Image and Zoom windows. They include output to an ENVI format image file, and output to BMP, HDF, JPEG, JPEG2000, PICT, PNG, SRF, TIFF (including GeoTIFF), and XWD files. ENVI can also output to various image processing format files including ERDAS (.lan), ER Mapper, PCI (.pix), and ArcView (.bil) files.

To output a displayed image to an image file, select File

Save Image As

Image File from the Image window menu bar. The Output Display to Image File dialog appears with options to select the type of output file, set the graphics overlay selections, select a spatial subset, resize the image, and change the border size. See the subsections below for details.

To output the contents of the Zoom window to an image file, select File

Save Zoom As

Image from the Image window menu, or right click on the image and select Save Image As. The Output Zoom to Image File dialog appears with options to select the type of output file and graphic overlay selection. See the following sections for details.

To output a plot or vector window to an image file, select File

Save Plot As

Image File in the plot or vector window. The Output Plot to Image file dialog appears with options to select the type of output file, set the graphics overlay selections, select a spatial subset, resize the image, and change the border size.

Selecting Output File Types and Resolutions

ENVI's output to image file supports many different output file types (listed above). Each file type has a selection of available output formats. These output formats (resolutions) include 8-bit grayscale, 8-bit with an associated color table, and 24-bit BSQ (band sequential), BIL (band interleaved by line), and BIP (band interleaved by pixel) formats.

To select the desired output file type, use the Output File Type drop-down button.

Note
When you output a georeferenced image to a JPEG file, an associated .jgw file is also created to contain the TIFF World File information. When you open a JPEG file (using File

Open External File

Generic File Formats

JPEG) that has a .jgw file associated with it, ENVI reads the map information from .jgw file.

Select the desired output format and resolution using the Resolution drop-down button.

Setting Graphics Overlay Options

Graphics options (annotations, grid lines, regions of interest, vectors, etc.) can be permanently incorporated in the output image file. All currently displayed valid ENVI graphics objects are automatically selected when the Output to Image File dialog is started. A border is automatically placed on the output image if grid lines are selected. The grid text-labels are placed exterior to the image. Note the grid must have been previously displayed and configured on the image using the Grid Lines option on the Image window menu (see Grid Lines).

Click on the Change Graphic Overlay Selections button. The Change Graphics Overlay Options dialog appears with a list of the currently displayed graphics objects.

Change the graphic overlay selections using the following options:

To remove a graphics overlay, click on its name in the Currently Selected Options list.

To add graphics overlays, select the desired overlay using the Add Graphics Option pull-down menu (with the exception of annotation, these overlays must be displayed on your image or plot).

Click OK to return to the Output to Image File dialog.

Changing Border Sizes and Colors

Click on the Change Image Border Size button.

When the Change Image Border Size dialog appears, enter the desired border sizes in the top, right, bottom, and left text boxes.

Select the desired border color from the pull-down menu. The corresponding RGB values appear in the text boxes.

Click OK to return to the Output to Image File dialog.

Subsetting Output Images

In the Output Display to Image File dialog, you have the option of selecting a spatial subset or specifying a resize factor.

To select a spatial subset of the image to output, click Spatial Subset to perform typical ENVI subsetting. For subsetting details, see Selecting a Spatial Subset.

To resize the input image, enter a resize factor (less than 1 for subsampling) in the Input Image Resize Factor text box.

The Input Image Resize Factor text box.

In the Output Plot to Image File dialog, you have the option of specifying the xsize and ysize of the image. The default xsize and ysize values are the size of the plot window.

The output size of the image, in pixels, is shown in the Output Image Size text box.

Applying Masks

In the Output Display to Image File dialog, you have the option of applying a predefined mask to your output image. This means that if you want to apply a mask to the image, you do not need to do it before selecting the output options.

Click Select Mask.

Select the input band for the mask.

In the Background R, G, and B boxes, enter desired color values that you want to use where the mask is turned off.

Click OK.

Note
To clear the selected mask and output a complete image, click Clear Mask.

Saving Output Image Files

Select output to File or Memory and enter an output filename if needed.

Click OK when all options are correctly set.

Printing

ENVI allows output of the image display, plot, and vector windows directly to system printers. You should be able to output to any of your system printers or plotters through your native system printer dialog.

Select one of the following options:

To output a displayed image to a system printer, select File

Print from the Image window menu bar.

To output a plot or vector window to a system printer, select File

Print in the plot or vector window.

When the Print setup dialog appears, set any options specific to your system and click OK.

When the Output Display to Printer dialog appears, you will have several options for setting the output display parameters. See the following subsections for detailed instructions.

After setting the parameters, click OK in the Output Display to Printer dialog to print the image or plot.

Selecting Output Print Sizes

You can set the output X or Y print size or set the desired output map scale if a georeferenced image displays. When a size is set, the other size parameters will change to preserve the aspect ratio of your image.

In the Output Display to Image File dialog, set the output image size on the page by entering the desired values into the xsize and ysize labeled text boxes.

Note
To maintain the relative aspect between X and Y when one dimension is changed, select the Aspect check box.

To position the image on the output page using your mouse, click and hold the left mouse button inside the image outline in the draw window and drag the image to a new position.

To center the image outline on the page using your mouse, click the right mouse button anywhere on the output page.

Click on the arrow toggle button to select Landscape or Portrait as the page orientation.

To scale an image to a specified map scale, enter the desired scale in the Map Scale 1: text box. The xsize and ysize values change automatically based on the image pixel size (a default size of 30 meters is assumed if no pixel size is present in the header).

Subsetting and Resizing Output Images

To select a spatial subset of the image to output, click on the Spatial Subset button to perform typical ENVI subsetting. For subsetting details, see Selecting a Spatial Subset.

To resize the image, enter a resize factor (less than 1 for subsampling) in the Input Image Resize Factor text box.

Setting Graphics Overlay Options

Graphics options (annotations, grid lines, regions of interest, vectors, etc.) can be permanently incorporated in the print. All currently displayed valid ENVI graphics objects are automatically selected when the Output Display to Printer dialog is started. A border is automatically placed on the output image if grid lines are selected. The grid text-labels are placed exterior to the image. Note the grid must have been previously displayed and configured on the image using the Grid Lines option on the Image window menu bar (see Grid Lines).

In the Output Display to Printer dialog, click on the Change Graphic Overlay Selections button. The Change Graphics Overlay Options dialog appears with a list of the currently displayed graphics objects.

Change the graphic overlay selections using the following options:

To remove a graphics overlay, click on its name in the Currently Selected Options list.

To add graphics overlays, select the desired overlay using the Add Graphics Option pull-down menu (with the exception of annotation, these overlays must be displayed on your image or plot).

Click OK to return to the Output Display to Printer dialog.

Applying Masks

In the Output Display to Printer dialog, you have the option of applying a predefined mask to your output image. This means that if you want to apply a mask to the image, you do not need to do it before selecting the output options.

Click Select Mask.

Select the input band for the mask.

In the Background R, G, and B boxes, enter desired color values that you want to use where the mask is turned off.

Click OK.

Note
To clear the selected mask and output a complete image, click Clear Mask.