Fitting an Image to a Projection

IDL gives you the ability to open image data within a map projection through iMap. IDL warps the image to fit the map automatically. In this example, we'll use IDL's automatic capabilities to open an image containing 1 km resolution global land cover data. (Image data courtesy of Reto Stöckli, NASA/Goddard Space Flight Center.)

  1. Open an iMap window by typing IMAP at the IDL command line.
    imap_selectmollweide.gif
  2. Select Operations →  Map Projection. This command opens the Map Projection dialog, shown here:
  3. Choose the Mollweide projection from the Projection pull-down list, then click OK.
  4. Now, open image data from the IDL examples files. Select File → Open and navigate to the IDL examples/data directory. Choose the file named Day.jpg.

    5. The IDL Map Register Image Step 1 dialog appears.

  5. Click Next to accept the default settings. Step Two of the IDL Map Register Image dialog appears, displaying the default data that IDL uses to fit the image to the projection.
  6. Click Finish to accept the default settings. In the iMap window, the image data display in the Mollweide projection:
    imap_day.gif

See also Warping Images to Maps.