Regions of Interest (ROIs) are selected samples of a raster, such equally areas of h2o, that are identified for a particular purpose. You can utilise ROIs for processing in some ENVI tools, such as to extract statistics for classification. To create and manage ROIs, click the Region of Involvement (ROI) Tool push on the toolbar. When you define an ROI, you specify the pixels of an image that volition be in or out of the ROI. For more data on the rules that decide when a pixel is included in an ROI, see the ROI Pixel Inclusion Background topic.

ENVI performs a real-time orthorectification for ROI layers created on elevation of an RPC image. The ROI layers will incorporate projected coordinates that tin display with other projected imagery, and projected ROI layers will display on top of an existing RPC epitome without reprojecting the RPC image.

The following are described in this section:

  • Create ROIs from Geometry
  • Create ROIs from Pixels
  • Grow ROI Polygons Using the Magic Wand Tool
  • Grow ROIs from Neighboring Pixels
  • Create ROIs from Band Thresholds
  • Catechumen ASCII Data to ROIs
  • Convert Feature Counts to ROIs
  • Catechumen GeoJSON Features to ROIs
  • Convert ROIs to Classification
  • Convert ENVI Classic ROIs to XML
  • Convert Vectors to ROIs
  • Study the Expanse of ROIs
  • Relieve and Export ROIs
  • Compute Statistics from ROIs
  • Create a Buffer Zone from ROIs
  • Merge ROIs
  • Pixelate ROIs
  • Ship ROIs to the northward-D Visualizer
  • Compute ROI Separability

Create ROIs from Geometry

To create ROIs from geometry, draw shapes or mark points on the raster layer. You can as well create multi-part ROIs, which are polygon, rectangle, or ellipse shapes that incorporate holes.

  1. In the Region of Interest (ROI) Tool, click the New ROI push button on the toolbar. In the Layer Manager, the selected raster in the Layer Manager becomes the parent to the new ROI layer that is added below it.
  2. Select the Geometry tab.
  3. Click the Polygon, Rectangle, Ellipse, Polyline, or Bespeak push. An ROI can contain any combination of these geometry.
  4. By default, vertices do not snap as y'all draw ROIs. To snap vertices, enable the Vertex Snap bank check box.

  5. Create ROIs in the Epitome window as follows:

    • Polygon or Polyline ROIs: Click to mark the vertices of the polygon or polyline, or click and drag to draw the shape. To complete the shape, press the Enter primal once, or right-click and select Complete shape_type . Until you "accept" the shape, it appears translucent and yous can edit its size or vertices, or motion it.
    • Rectangle or Ellipse ROIs: Click and drag to draw the rectangle or ellipse. Until yous "take" the shape, it appears translucent and you can edit its size or vertices, move it, or rotate it.
    • Point ROIs: Click to marking points. Until yous "accept" the points, they announced as crosshairs.

    When calculation whatever shape or point, you tin press the Delete key to clear it, or correct-click and select Clear shape_type . For polygons or polylines, press the Backspace key to delete the last vertex fatigued.

    With polygons, you lot can employ a shortcut to draw a rectangle at an angle: Click two vertices to define one side of the rectangle. These two points make up one's mind the angle at which the rectangle will be drawn. Press and concur the Shift key and drag the previewed rectangle to the end of the object. Click the mouse when you are fix to accept the rectangle.

    You can also rotate a ROI every bit follows: Draw a shape, then right-click in the view and select Consummate shape type . Move the cursor near the center handle and click the Shift primal. A rotation icon appears (see the circled icon in the figure below). Click and drag to rotate the object as needed, then release the mouse key.

  6. Printing the Enter key a second time to take the shape or points, or right-click and select Accept shape blazon . The new ROI is added to the ROI layer, and the Record Count in the ROI Tool increments. Once accepted, a shape appears in solid color. If you marked ROIs every bit points, the advent of the points changes from crosshairs to marked pixels.
  7. Assign an ROI Name and change the ROI Color as needed.

To create a multi-part ROI from a polygon, rectangle, or ellipse:

  1. In the Geometry tab, click the Polygon, Rectangle, or Ellipse button.
  2. Enable the Multi Office check box.

  3. Draw the shape to create the first part.

  4. Printing the Enter key twice to complete the part, or right-click and select Consummate shape Part. The shape appears in a transparent color as you draw the 2d role on top of it to create the hole.

  5. Depict the second part. The shape must be contained within the premises of the first part.

    Tip: To remove all holes from the current shape, correct-click and select Remove Holes.

  6. Press Enter to complete the shape, or correct-click and select Complete shape Part. A hole displays in the ROI.

  7. Press Enter a last time to take and consummate the multi-function, or right-click and select Accept Multi Part.

Edit Geometry ROIs

To edit geometry ROIs, click the Go To pointer buttons at the bottom of the ROI Tool to navigate the private records of the selected ROI layer. As you click through the individual ROIs, the Image window centers over the each tape. To navigate to a different ROI layer, click the Select Next ROI button on the toolbar.

Notation: Editing functions are disabled if the ROI has been reprojected onto a base paradigm layer that has a different resolution or map information.

  • To edit a record, right-click the record in the Image window and select Edit Record. Move or resize the shape by dragging the selection handles. Movement vertices by dragging the circles that appear when you hover over the shape. Add a new vertex earlier or after a option by pressing the keyboard keys + and -, or past correct-clicking and selecting from the bill of fare options. To have the edits, right-click and select Have shape type , or press the Enter cardinal.
  • To edit the size of the rectangle or ellipse before the shape is accepted, click the edges of the box and drag, or right-click on the shape and select Rectangle Size or Ellipse Size to enter verbal values in the Edit Size dialog. To move the shape, click within it and drag.
  • To indistinguishable a record and move it to another location, correct-click the record in the Image window and select Duplicate Tape. Movement or resize the shape by dragging the selection handles as needed. To take the edits, right-click and select Accept shape blazon , or press the Enter key.
  • To delete a single tape, right-click the record in the Prototype window and select Delete Tape. You tin also click the Delete Record button in the ROI Tool.
  • To delete all records from an ROI, select the Delete All Records push button in the ROI Tool.

You tin can also delete a group of polygon, rectangle, or ellipse ROI records at once. Follow these steps:

  1. Select the Geometry tab in the Region of Involvement (ROI) Tool.
  2. Hold downward the Shift cardinal and left mouse push button simultaneously. The cursor changes to a minus symbol (-).
  3. Drag the cursor to draw a polygon around the ROI records that you want to remove.
  4. Release the left mouse button. The selected ROI records are removed.

This action cannot be undone. To abort the selection while you are drawing a polygon, click the right mouse button (while standing to hold down the left mouse push).

Create ROIs from Pixels

To create ROIs from pixels, select pixels on the raster layer. Y'all tin can select a single pixel at a time (1x1), or up to an area of 5x5 pixels at a time.

  1. In the ROI Tool, click the New ROI push button on the toolbar. In the Layer Managing director, the selected raster in the Layer Manager becomes the parent to the new ROI layer that is added below information technology.
  2. Select the Pixel tab.
  3. Select the Brush Size from the driblet-down list. Y'all tin select 1x1, 2x2, 3x3, 4x4, 5x5, 10x10, and 25x25 pixels for the castor size.
  4. In the Paradigm window, click a pixel, or click and drag to "pigment" an area of pixels.
  5. Assign an ROI Proper noun and modify the ROI Color as needed.

Edit Pixel ROIs

To edit pixel ROIs, click the Get To pointer buttons at the bottom of the ROI Tool to navigate the individual records of the selected ROI layer. As yous click through the individual ROIs, the Image window centers over the each record. To navigate to a different ROI layer, click the Select Adjacent ROI button on the toolbar.

Annotation: Editing functions are disabled if the ROI has been reprojected onto a base image layer that has a different resolution or map information.

To delete an individual pixel, place the selection box cursor over the pixel. Zoom into the view if needed. Then right-click and select Delete Pixel, or printing the Delete fundamental. If y'all added pixels using a brush size larger than 1x1, y'all can also delete the pixel group every bit a whole, or simply part of it.

To delete all pixels from an ROI, select the Delete All Pixels button in the ROI Tool.

You can also delete a group of pixel ROIs at once. Follow these steps:

  1. Select the Pixel tab in the Region of Interest (ROI) Tool.
  2. Hold down the Shift key and left mouse button simultaneously. The cursor changes to a minus symbol (-).
  3. Elevate the cursor to draw a polygon around the pixel ROIs to remove.
  4. Release the left mouse button. The selected pixels are removed.

This action cannot be undone. To arrest the selection while you are cartoon a polygon, click the correct mouse push (while standing to hold downward the left mouse button).

Grow ROI Polygons Using the Magic Wand Tool

Manually cartoon polygons around complex objects such as clouds, tree crowns, and lakes can exist time-consuming and labor-intensive. In these cases, you can use the Magic Wand tool to grow complex polygons from one or more "seed" pixels. Follow these steps:

  1. In the ROI Tool, click the New ROI button on the toolbar.
  2. Select the Geometry tab in the ROI Tool.
  3. Click the Polygon button.
  4. Find an object in your image whose shape you desire to capture.
  5. Hold downward the Ctrl fundamental, then click on a pixel inside of the object. The Magic Wand Parameters dialog appears. ENVI grows the region effectually the seed pixel by including neighboring pixels that are within the specified Threshold value. Here is an example within a cloud:

  6. Adjust the Threshold value to shrink or aggrandize the current region. The range of values is 0 to 255, where 0 is the seed pixel and 255 is the entire image. The Magic Wand tool calculates thresholds based on the byte-stretched information that is displayed in the view.
  7. Optional: You tin experiment with different Bands to use options to improve the initial polygon result. For multispectral images, the choices are:RGB (default), Cherry-red, Green, Blue, HSI, Hue, Saturation, Intensity. For unmarried-ring images, the only selection is Grayness Calibration.

    8. If the size of the region exceeds the Tile Size (1000 pixels by default), and the Utilise Pyramids choice is enabled, the Magic Wand tool will employ a coarser pyramid level to abound the region. This allows large regions to be represented by a polygon only at a reduced pixel resolution; for instance:

    If you disable the Use Pyramids option, then the polygon volition be at full pixel resolution merely will simply grow equally large as the specified Tile Size.

  8. Use Ctrl-click to add more seed points inside the same object to help it abound correctly. Or, add together more seed points to similar objects to create a multi-part polygon. The Number of Seed Points is incremented. To remove the last seed point, click the Remove Seed Point push button .
  9. To remove all holes inside of a polygon, right-click and select Remove Holes. This will make the polygon a solid object.
  10. To delete the current polygon, right-click and select Clear Multi Part or Clear Polygon.
  11. Once y'all are satisfied with the extent of the polygon, correct-click and select Have Multi Function or Have Polygon. Here is an example result:

Grow ROIs from Neighboring Pixels

To abound ROIs from neighboring pixels, select an ROI that was previously created and set a threshold. The threshold defines the number of standard deviations away from the mean of that selected tape. Employ either 4 or 8 neighboring pixels to decide the growth pattern. The surface area to grow is calculated using the displayed ring for a gray scale display, or the R,G,B bands for a color display.

  1. In the Geometry tab or Pixel tab of the Region of Interest (ROI) Tool, use the arrow keys to navigate to the record yous want to grow.
  2. Select the Grow tab.
  3. Set up the Max Growth Size in pixels. This determines the maximum size the ROI tin can grow to.
  4. Enter a value for the Std Dev Multiplier. The standard deviation multiplier sets how many standard deviations away from the mean of the fatigued ROI to include in the grown ROI.
  5. Enter the number of Iterations to perform to abound the ROI. The higher the number of iterations, the more pixels that volition be included in the concluding ROI.
  6. Enable the 8 Neighbors check box to employ the eight nearest-neighbour pixels. If this cheque box is disabled, then only the four nearest-neighbor pixels will be used.
  7. Click Apply.
  8. Repeat this process and change the settings every bit needed until yous attain the desired upshot. To reset the ROI to its original country earlier you grew the ROI, click Reset.

To edit the ROIs, click the Get To pointer buttons at the bottom of the ROI Tool to navigate the individual records of the selected ROI layer. As you lot click through the individual ROIs, the Image window centers over the each tape. To navigate to a different ROI layer, click the Select Next ROI push on the toolbar.

Notation: Editing functions are disabled if the ROI has been reprojected onto a base image layer that has a different resolution or map information.

  • To delete pixels, place the option box cursor over the pixel to remove (zoom into the view, if needed), then right-click and select Delete Pixel, or press the Delete cardinal.
  • To delete all pixels from an ROI, select the Delete All Pixels button in the ROI Tool.

Create ROIs from Band Thresholds

To create ROIs from band thresholds, set specific image values or ranges of values.

You can write a script to perform this job using the ImageThresholdToROI job.

  1. Do i of the post-obit:

    • In the ROI Tool, click the New ROI push button on the toolbar. In the Layer Manager, the selected raster becomes the parent to the new ROI layer that is added below it. In the ROI Tool, select the Threshold tab, then click the Add New Threshold Rule button .

    • From the Toolbox, select Regions of Interest > Ring Threshold to ROI.

    A new ROI is added to the Layer Manager, and the File Pick dialog appears.

  2. Select a band to threshold, and click OK. The Cull Threshold Parameters dialog appears, which includes a histogram of the band. To change the selected band, click .

  3. Use the Min Value and Max Value fields to define the ROI as follows:

    • Enter simply a Min Value to create an ROI using pixels that are greater than or equal to the value.
    • Enter only a Max Value to create an ROI using pixels that are less than or equal to the value.
    • Enter both minimum and maximum values to create an ROI using pixels that autumn within the specified range.

    You tin can also utilize the histogram to select the pixels to include in the ROI. Click and drag the color bars inside the histogram to select pixels. If you accessed the threshold tool from the Threshold tab, you tin enable the Preview check box to view the selected pixels in the Image window.

  4. Click OK to accept the ROI. If y'all accessed the band threshold tool from the Threshold tab, the ROI automatically loads in the Image window. If you accessed the tool from the Toolbox, open up the Data Manager and load the ROI. ENVI lists the ROI in the ROI Tool by the name of the ring used to excerpt the ROI.
  5. To assign an ROI proper name and modify the default ROI color, edit ROI Name and ROI Color values. You can also edit the Min and Max values in the tabular array in the Threshold tab.

Catechumen ASCII Data to ROIs

You can create ROIs from ASCII text files or comma-separated value (CSV) files that contain data and geolocation values. An example is creating a point-based ROI from an ASCII file that contains GPS records. The ROI will incorporate i record consisting of all of the data points.

Yous can write a script to convert ASCII data to ROIs using the ASCIIToROI chore.

If the data comprise a combination of numeric and text values, they must be separated by commas. If the data consist entirely of numeric values, they tin can be separated past spaces or commas. You can add records to a new or existing ROI. ENVI volition ignore whatever header information or column labels.

Tip: The ENVI Feature Counting Tool provides an pick to export feature counts to CSV files or ASCII reports.

Follow these steps:

  1. From the Region of Involvement Tool menu bar, select File > Import > Import from ASCII. A Select Input Coordinates File dialog appears.
  2. Select an ASCII text file (.txt) or CSV file (.csv) with the records y'all desire to import and click Open. The Import from ASCII dialog appears.

    3. The File Preview section shows the columns of information that were imported; for example:

  3. In the X field of Data Columns, select the column number that contains longitudes or eastings.
  4. In the Y field of Data Columns, select the column number that contains latitudes or northings.

    5. Using the case above, the X field is column #three since that column contains longitudes. The Y field is column #2 since that column contains latitudes:

  5. From the Geometry Type drop-down list, select the ROI geometry blazon to create. The choices are Polygon (default), Polyline, or Point.
  6. Select the Coordinate Arrangement of the imported ASCII data. See Select Coordinate Systems for further instructions. The default is Geographic Lat/Lon WGS-84.
  7. Click OK. The ROI geometry displays over the image that is associated with the ROI.

Convert Feature Counts to ROIs

You can create point ROIs from a saved feature count file (.efc). The ROI will accept the same colour equally the feature counts.

You tin can write a script to convert characteristic counts to ROIs using the FeatureCountToROI task.

Follow these steps:

  1. From the Toolbox, select Regions of Interest > Convert Feature Count to ROI. The Characteristic Count to ROI dialog appears.

  2. Select an Input Characteristic Count File (.efc).

  3. Specify an Output ROI location and filename (.xml).

  4. To run the process on a local or remote ENVI Server, click the down arrow and select Run Task in the Groundwork or Run Task on remote ENVI Server name. The ENVI Server Task Console volition prove the progress of the job and volition provide a link to brandish the issue when processing is complete. See the ENVI Servers topic for more data.

  5. Click OK. ENVI adds the outcome to the Data Manager.

Catechumen GeoJSON Features to ROIs

Yous can convert GeoJSON features to one or more than ROIs. GeoJSON is a geospatial format based on JSON lawmaking that is used for encoding geographic data structures. For more information, see the GeoJSON Format Specification. Also see the GeoJSONLint web page for example code and for tools that validate GeoJSON code.

You can write a script to catechumen GeoJSON features to ROIs using the GeoJSONToROI task.

Follow these steps:

  1. From the Region of Interest Tool menu bar, select File > Import > Import From GeoJSON. A Select Input GeoJSON File dialog appears.
  2. Select a .json file and click OK. The Import ROIs from GeoJSON dialog appears.
  3. Choose how to import the GeoJSON features into ROIs:
    • If the GeoJSON file contains i feature, the "ROI to import" field lists that characteristic. If an existing ROI is open up in ENVI, you tin select Merge with active ROI proper name. Or, select Import as new ROI to create a new ROI from the GeoJSON feature.
    • If the GeoJSON file contains multiple features, select the ROIs that you lot want to import. If an existing ROI is open in ENVI, you can select Merge with active ROI name. Or, select Import as new ROIs to create a new, individual ROIs from the GeoJSON features.
  4. Click OK.

Catechumen ROIs to Classification

You can convert selected ROIs into an ENVI classification image. The grade colors are the same equally the ROI colors.

You tin also write a script to convert ROIs to a nomenclature image using the ROIToClassification task.

  1. Do one of the following:

    • From the Region of Interest Tool carte bar, select Options > Create Classification Image from ROIs.
    • From the Toolbox, select Regions of Interest > Convert ROIs to Nomenclature.

    The Convert ROIs to Classification dialog appears.

  2. Select an Input Raster and perform optional spatial and spectral subsetting.
  3. Select the Input ROIs.
  4. Specify a filename and location for the Output Raster (the classification raster).
  5. Enable the Preview cheque box to see a preview of the settings before you click OK to process the data. The preview is calculated just on the area in the Image window. See Preview for details on the results. To preview a different area in your prototype, pan and zoom to the surface area of interest and reenable the Preview option.
  6. Enable the Display result bank check box to display the output rule raster and/or output rule raster in the Image window when processing is complete. Otherwise, if the check box is disabled, the raster can exist loaded from the Data Director.

  7. To run the process on a local or remote ENVI Server, click the down arrow and select Run Task in the Background or Run Job on remote ENVI Server name. The ENVI Server Job Console volition show the progress of the chore and volition provide a link to display the consequence when processing is complete. See the ENVI Servers topic for more than data.

  8. Click OK. ENVI adds the resulting output to the Data Manager and, if the Display Upshot cheque box was enabled, adds the layer to the Layer Manager and displays the output in the Epitome window.

Convert ENVI Classic ROIs to XML

ENVI Archetype ROIs (.roi) have the same spatial size equally their parent raster and cannot be displayed on rasters with a different resolution unless they are converted and saved to an .xml file. To convert the .roi to a georeferenced .xml, do the following:

  1. With a raster open and displayed, open an ENVI Classic .roi through the File menu or the Data Manager. The Choose Associated Raster of the Classic ROIs dialog appears.
  2. Select the raster to associate, then click OK. The ROIs open in the Layer Manager and the Epitome window, but the layer is non however saved to .xml.
  3. In the Layer Manager, correct-click the Region of Interest folder and select Save Equally. The Save Regions to .XML dialog appears.
  4. Enter a output filename, and click OK.

Convert Vectors to ROIs

To create ROIs from vectors, import a vector file, then select the vector records to convert. You can convert the records and add them to an existing ROI, or you tin convert them and create a new ROI.

You can write a script to create ROIs from geometry records using the following tasks:

VectorAttributeToROIs

: create ROIs from specific attributes in a vector file.

VectorRecordsToROI

: create a single ROI from all geometry records in a vector file.

VectorRecordsToSeparateROI: create individual ROIs from each geometry tape in a vector file.

  1. Exercise one of the post-obit:

    • From the Region of Involvement Tool carte du jour bar, select File > Import > Import Vector.
    • From the Toolbox, select Regions of Interest > Vector to ROI.

    The Select Input File Associated dialog appears.

  2. Select a .shp file, then click OK. The Convert Vector to ROI dialog appears.

  3. Select from the following conversion parameters.

    • All records to a single ROI converts the vector records to 1 ROI.
    • Each tape to a divide ROI converts each vector record to an individual ROI.
    • If unique records are saved in the shapefile, select Unique records of an aspect to divide ROIs to convert vector records of an aspect type to separate layers. For example, vectors with a CLASS_ID of 0 are grouped in i ROI, vectors with a CLASS_ID of ane are grouped in some other ROI, and so along. Select the Attribute to apply from the drop-down list that appears.
    • If unique attributes are saved in the shapefile, select Specific aspect query to convert vectors of the selected aspect type to a single ROI. For example, vectors with the CLASS_NAME water are converted to an ROI. Select the attribute to apply from the drib-down listing that appears.
    • To select a subset of the vector records to output to a unmarried ROI, select Record subset to a unmarried ROI, then click Select Record Subset to select the records from a table every bit follows:
    • The Number of Output ROIs shows how many ROIs will exist output, based on your conversion choice.
  4. Select whether to output the ROIs to a New ROI or add them to the Agile ROI.
  5. By default, the conversion results display in the Image window view. Disable the Display Results check box if you lot exercise not want the results to display.
  6. Click OK to convert the vectors.

Written report the Expanse of ROIs

You tin view a report of the area covered by each ROI in meters, kilometers, feet, U.Southward. survey feet, yards, miles, nautical miles, acres, hectares, or units squared.

The pixel count relates to the resolution of the image on which the ROIs are displayed. If an ROI was defined by choosing a discrete point, that point e'er defines a single pixel for the ROI, regardless of the resolution of the image. And so whether the image comprises 1-meter pixels or ten-meter pixels, the selected point translates to a unmarried, 1-meter pixel. If an ROI was divers past selecting a single pixel, information technology is different than choosing a discrete point. In this instance, the number of pixels included in the ROI is affected by the resolution of the image. If an image comprises 1-meter pixels, then an ROI defined by a unmarried pixel translates to x 1-meter pixels, and an image that comprises 10-meter pixels translates to 100 1-meter pixels.

  1. At the lesser of the ROI Tool, click the Area tab to expand it.
  2. Select the units to use in the report from the driblet-downward list.
  3. The ROI size is reported in the Area tab. If you are working with a very large image, the Pixel Count Refresh button is enabled. Click the button to refresh the pixel count for the ROIs.
  4. To save ROI Area Information to an ASCII File, click the Export Areas to ASCII button.

Salvage and Consign ROIs

To relieve ROIs to the current file format:

  • From the Region of Interest Tool card bar, select File > Save.
  • From the Layer Manager, right-click the Region of Interest folder or an private ROI and select Save.

To relieve ROIs to XML format:

  • From the Region of Interest Tool menu bar, select File > Save As. Select the ROIs to output and provide a filename, then click OK.
  • From the Layer Manager, right-click the Region of Involvement binder or an individual ROI and select Save As. Select the ROIs to output and provide a filename, then click OK.

To export ROIs to other formats:

  • From the Region of Interest Tool bill of fare bar, select File > Export > Export to Classic to salvage to a .roi file format.
  • From the Region of Interest Tool menu bar, select File > Consign > Export to Shapefile to save to a .shp file format.
  • From the Region of Interest Tool card bar, select File > Export > Consign to CSV to save to a .csv file format.
  • From the Region of Involvement Tool menu bar, select File > Export > Export to GeoJSON to save to a .json file format.

Compute Statistics from ROIs

You tin summate statistics for the pixels in the ROI, including:

  • Pixel count per ROI.
  • Basic statistics (minimum, maximum, mean, and standard divergence) for single- or multi-band images.
  • Histograms (frequency distributions) for single- or multi-band images.

For details, see Region of Interest Statistics.

Create a Buffer Zone from ROIs

Y'all can calculate a buffer zone epitome from the original paradigm. In the resulting buffer zone image, every pixel has a floating-point or integer value that is defined as the altitude from that pixel to the nearest pixel of the selected ROI. Designate a maximum distance value, and the result is that whatever pixels with a distance larger than that value are gear up to the maximum distance value.

  1. Do i of the following:

    • From the Region of Involvement Tool menu bar, select Options > Create Buffer Zone from ROIs.
    • From the Toolbox, select Regions of Involvement > Buffer Zone from ROIs.

    The Buffer Zone from ROIs dialog appears.

  2. Select an Input Raster and perform optional spatial and spectral subsetting.

  3. Select the Input ROIs.
  4. Select an option from the Output Data Type drop-down list. The choices are Integer (default) or Float.
  5. Optional: Specify the Maximum Altitude, in pixels, for the buffer zone.
  6. Specify a filename and location for the Output Raster (the classification raster).
  7. Enable the Preview check box to see a preview of the settings before y'all click OK to process the information. The preview is calculated only on the area in the Image window. Come across Preview for details on the results. To preview a dissimilar area in your image, pan and zoom to the surface area of interest and reenable the Preview pick.

  8. To run the procedure on a local or remote ENVI Server, click the down arrow and select Run Task in the Background or Run Job on remote ENVI Server name. The ENVI Server Job Console will show the progress of the task and will provide a link to display the event when processing is complete. Run across the ENVI Servers topic for more information.

  9. Click OK. ENVI adds the resulting output to the Data Manager and, if the Brandish Result check box was enabled, adds the layer to the Layer Manager and displays the output in the Image window.

Merge ROIs

Y'all tin can merge multiple ROIs into a unmarried ROI, such every bit create a union or intersection.

  1. Do one of the following:

    • From the Region of Interest Tool menu bar, select Options > Merge (Matrimony/Intersection) ROIs.
    • From the Toolbox, select Regions of Interest > Merge (Union/Intersection) ROIs. The File Choice dialog appears. Select the input raster and click OK.

    The Merge Regions dialog appears.

  2. Select the ROIs to merge, or click Select All Items if you want to merge all.
  3. Enable the Delete Input ROIs check box to remove the private ROI layers from the Layer Director and Data Manager after they are merged into a unmarried, new layer. If you leave this check box disabled, the individual ROI input layers remain open up.
  4. Click OK. ENVI creates a new layer for the merged ROIs named Region #due north. You lot can then load the merged ROI layer through the Information Director.

Pixelate ROIs

To pixelate ROIs:

  1. From the Region of Interest Tool menu bar, select Options > Pixelate ROIs. The Choose Regions dialog appears.
  2. Select the ROIs to pixelate.
  3. Click OK.

Send ROIs to the due north-D Visualizer

Yous can export selected ROIs to the n-D Visualizer and then you can run into the distribution of the points inside and between the ROIs. This choice is useful for checking the separability of your classes when you use ROIs equally input into supervised classifications.

For good classification results using these ROIs, the groups of pixels for the different ROIs should be split up from each other and should non overlap. If the pixels overlap, edit the groups of pixels by selecting the appropriate colors from the Class menu to add pixels to an ROI or past selecting White to remove pixels from an ROI.

  1. From the Region of Interest Tool menu bar, select Options > Transport ROIs to n-D Visualizer. The Choose Regions dialog appears.
  2. Select the ROIs to include in the n-D Visualizer.
  3. Click OK. The n-D Visualizer window and n-D Controls dialog appear.
  4. Select the ring numbers for rotation.
  5. Click Start. The pixels for the selected ROIs appear in the n-D Visualizer window in the same colors every bit the ROIs.

For a description of the n-D Visualizer window, run into n-D Visualizer/Controls Options.

Compute ROI Separability

Apply the ROI Separability tool to compute the spectral separability betwixt selected ROI pairs for a given input file. Both the Jeffries-Matusita and Transformed Deviation separability measures are reported. These values range from 0 to 2.0 and signal how well the selected ROI pairs are statistically divide. Values greater than 1.9 indicate that the ROI pairs have practiced separability. For ROI pairs with lower separability values, you should attempt to improve the separability by editing the ROIs or by selecting new ROIs. For ROI pairs with very depression separability values (less than 1), you lot might want to combine them into a unmarried ROI.

References:

J.A. Richards, 1999, Remote Sensing Digital Paradigm Analysis, Springer-Verlag, Berlin, p. 240.

H. Jeffreys, "An Invariant for the Prior Probability in Estimation Problems," Proc. Roy. Soc. A., Vol. 186, pp. 454-461, 1946.

  1. Practise one of the following:

    • From the Region of Interest Tool menu bar, select Options > Compute ROI Separability.
    • From the Toolbox, select Regions of Interest > ROI Separability. The Select Input File for ROI Separability dialog appears. Select the file and click OK.

    The ROI Separability Calculation dialog appears.

  2. Select ROIs for the separability adding.
  3. Click OK. The separabilities are calculated and reported in a ROI Separability Report dialog. Both the Jeffries-Matusita and Transformed Divergence values are reported for every ROI pair. The end of the report shows the ROI pair separability values listed from the least separable pair to the most separable.
  4. To save the report to an ASCII file, select File > Save Text to ASCII.

See Too

Region of Interest Shortcuts, Region of Interest Layers