Use Reproject Raster to reproject georeferenced images to another projected coordinate system. ENVI performs a reprojection by first converting the input dataset's map extents into the selected output coordinate system to determine the output map extents. Based on the warping method that you specify, any number of pixels in the input dataset are reprojected into an output raster dataset using the reprojected map extents and the selected output coordinate system.

You can also use this tool to convert from a Rational Polynomial Coefficient (RPC) model, pseudo projection, or Geographic Lookup Table (GLT) to a standard Geographic Lat/Lon WGS-84 projection. In these cases, the input and output coordinate system strings can be the same.

You can also write a script to reproject images using the ReprojectRaster task.

  1. From the Toolbox, select Raster Management > Reproject Raster.
  2. Select an Input Raster and perform optional spatial and spectral subsetting, and/or masking.
  3. Choose an option to select an Output Coordinate System:
    • Click the Browse button . The Select Coordinate System dialog appears. Refer to the Select Coordinate Systems topic for instructions on choosing a pre-defined or custom coordinate system.
    • To use the coordinate system from another dataset, click the From Dataset button .
    • To use the coordinate system of the current view, click the From Current View button .
    • To reset the selection, click the Reset button .
  4. From the Reprojection Method drop-down list, select a warping method. The choices are Polynomial, Triangulation (default), and Rigorous. The rigorous method is the most accurate because it reprojects every pixel in the input image, but it is also the slowest.
  5. From the Resampling Method drop-down list, select a method for interpolating the input pixels to the output raster dataset. The options are Nearest Neighbor (default), Bilinear, and Cubic Convolution. The cubic convolution method is the most accurate but also the slowest.
  6. Optional: Enter a pixel value in the Data Ignore Value field that represents the output image background value. All pixels outside of the warped-image boundary will be set to this value.
  7. Specify the filename and location for the Output Raster.
  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.

See Also

Overview of Map Information in ENVI, Reproject Vectors