Resize Rasters

Use Resize Raster to resample a raster to different dimensions.

You can also write a script to resample / resize rasters using the following tasks: DimensionsResampleRaster, MappingResampleRaster, and PixelScaleResampleRaster. Or, use the ENVIResampleRaster routine.

  1. From the Toolbox, select Raster Management > Resize Raster. A Data Selection dialog appears.
  2. Select an input raster and perform optional spatial and/or spectral subsetting, and masking.
  3. Click OK. The Resize Raster dialog appears. The Image Size values are automatically populated based on the original image size.
  4. Change the output dimensions by setting the Image Size, Resize Factor, or Pixel Size values. When you specify any of these values, the other values will update accordingly to provide the same geographic extent as the input raster.
    • Image Size: The first value is the number of columns (x). The second value is the number of rows (y).
    • Resize Factor: This is the factor by which you will reduce or enlarge the image, in the x and y directions. For example, a Resize Factor value of 4 (x and y) for an input raster that is 200 x 200 pixels will produce a 800 x 800 raster that covers the same geographic extent as the input raster.
    • Pixel Size: Use these values to set the desired pixel size of the output raster. Columns and rows will update accordingly.
  5. Enable the Lock Aspect Ratio option to maintain the original aspect ratio of the raster as you change any of the x or y dimension values.
  6. Select a resampling option from the Resampling Method drop-down list. The choices are as follows:
    • Nearest Neighbor (default): Uses the nearest pixel without any interpolation.
    • Bilinear: Performs a linear interpolation using four pixels to resample.
    • Cubic Convolution: Uses 16 pixels to approximate the sinc function using cubic polynomials to resample the image.

  7. To write the output to disk, select the File radio button and specify a filename and location. To produce output in memory only, select the Virtual radio button.

  8. Enable the Display result check box to display the output in the view when processing is complete. Otherwise, if the check box is disabled, the result can be loaded from the Data Manager.

  9. To reuse these task settings in future ENVI sessions, save them to a file. Click the down arrow and select Save Parameter Values, then specify the location and filename to save to. Note that some parameter types, such as rasters, vectors, and ROIs, will not be saved with the file. To apply the saved task settings, click the down arrow and select Restore Parameter Values, then select the file where you previously stored your settings.

  10. To run the process in the background, click the down arrow and select Run Task in the Background. If an ENVI Server has been set up on the network, the Run Task on remote ENVI Server name is also available. The ENVI Server Job Console will show the progress of the job and will provide a link to display the result when processing is complete. See ENVI Servers for more information.

  11. Click OK.