Use Georeference Data to georeference your HDF and CEOS format SeaWiFS data. ENVI extracts the header information for CEOS or HDF format SeaWiFS data and does a precision geocoding of the data based on a complete geometry model of the earth and satellite orbit.

Note: We recommend that you use the more accurate technique, Georeference from Input Geometry, instead of CEOS or HDF Georeference Data.

  1. Open a SeaWiFS file by selecting File > Open for HDF4 files or File > Open As > Optical Sensors > SeaWiFS > CEOS for CEOS files.
  2. Select one of the following from the Toolbox:
  • Geometric Correction > Georeference by Sensor > Georeference SeaWiFS CEOS
  • Geometric Correction > Georeference by Sensor > Georeference SeaWiFS HDF
  1. Select an input file and perform optional spatial and spectral subsetting, then click OK.
  2. If your input file is not in HDF or CEOS format, select the associated HDF or CEOS annotation file to read the header information from.
  3. Click OK. The Georeference SeaWiFS Parameters dialog appears.
  4. Select the desired output map projection from the list.

  5. Enter X and Y values for Number of Warp Points.

    You may select a number of warp points up to the number of samples and lines in your image. If you select fewer warp points, they will be evenly spaced throughout the image.

    To save the warp points to a GCP file, enter or choose an output filename.

    Note: Using many warp points increases the warping time considerably, but can significantly increase the accuracy of the georeferencing.

  6. Click OK. The Registration Parameters dialog appears.
  7. Select the warping and resampling methods and change the output dimensions, if desired. The triangulation method is recommended to produce the most accurate results. Note, however, that it will be much slower than polynomial warping.
  8. Select output to File or Memory.
  9. Click OK.