Region of Interest Layers

Region of Interest (ROI) layers are loaded as sub-layers of a raster. See the following sections for details:

• Open, Load, and Manage ROIs
• ROIs, EVFs, and Shapefiles as Input

Open, Load, and Manage ROIs

Open a file, as described in Open and Display Files. Supported ROI input formats include .xml files created with the Region of Interest (ROI) Tool, .shp files, and ENVI Classic .roi and .evf files.

When ROIs contain map information, such as those created from the Region of Interest (ROI) Tool or certain .xml files, they can be displayed with any raster that contains a compatible geographic overlap. If the base raster visualization contains a different resolution or map projection than the ROI definition, the ROI visualization layer will be reprojected to match the base raster. For information on how ROI reprojection works, see ROI Pixel Reprojection Background. A single ROI may contain multiple pixel and geometry definitions in different resolutions and projections; however, the Region of Interest (ROI) Tool only allows direct manipulation of definitions that match the current resolution and projection of the base raster visualization.

ENVI cannot reproject ROI pixel, threshold, and geometry definitions that were created without map information.

To manage ROI layers:

• To edit the name or color properties of an ROI, right-click the ROI in the Layer Manager and select Properties. The Edit ROI Properties dialog appears. Property changes apply to the edited ROI in the Data Manager display and the Layer Manager.
• To revert the most recent change to ROIs, from the Layer Manager, right-click the Regions of Interest folder or right-click the ROI and select Revert.
• To save changes to ROIs, see Save ROIs.
• To center an ROI in the Image window view, right-click the ROI and select Go to Item.
• To view statistics for an ROI, from the Layer Manager, right-click the Regions of Interest folder and select Statistics for All ROIs. Or, right-click the ROI and select Statistics.
• To remove all ROIs, from the Layer Manager, right-click the Regions of Interest folder or the individual ROI and select Remove. When you remove ROIs from the Layer Manager, they remain open in the Data Manager where you can access them for redisplay.
• You can change the transparency of ROIs with the Transparency tool. In the Layer Manager, select an individual ROI or select the Regions of Interest folder, then apply transparency.

ROIs , EVFs, and Shapefiles as Input

• When a tool accepts ENVI Classic .roi or .evf files as input, select the file as described in the help steps for that tool. The .roi or .evf file can be open before you start the tool, or open the file when you are prompted to input ROIs.
• When using an ROI .xml file as ROI input, open the file before starting the tool.
• When using a .shp file as ROI input, open the shapefile before starting the tool. When prompted to input ROIs, the shapefile will be available in the selection list.
• To convert ENVI Classic .evf files to a shapefile, see Convert an ENVI Classic .evf File to a Shapefile.
• To convert ENVI Classic .roi files to a shapefile, see Convert an ENVI Classic .roi File to a Shapefile.