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 next to the OK button , select Save Parameter Values, then specify the path 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 saved your settings.

  10. You can run the process in the background on your computer or in the background on an ENVI Server (if available). Click the down arrow next to the OK button and select one of the following:

    • Run Task in the Background: Runs the process on your computer. This method does not use an ENVI Server. The job progress will show in the ENVI Job Console's Background Jobs tab.
    • Run Task on envi_server_name. Runs the process on the selected ENVI Server. The job progress will show in the ENVI Job Console's envi_server_name tab.

    See ENVI Job Console for details on monitoring ENVI Server jobs and viewing results. See ENVI Servers for details on configuring and using an ENVI Server.

  11. Click OK.