Applying the NDVI process

This is a workflow you can use to apply the NDVI process to a Landsat scene. You can easily adapt this to any raster dataset with red and near-infrared bands.

步骤：

1. Create a new image service definition using the defaults—three bands, unsigned 8-bit integer pixel type, 8 bits, RGB—and specify the spatial reference system specific to your dataset.
2. Add the raster data by clicking the Image Service drop-down menu on the Image Service Definition Editor toolbar, clicking Advanced > Add Raster Dataset, then clicking and adding the Landsat scenes using the Landsat-7 Level 1G raster type in the Georeferenced Imagery folder. Specify the Band-3 in the Input for Band 1 box and Band-4 for Input for Band 2; the inputs for the other bands do not matter, since they are not being used. Also uncheck Pan-sharpening, leave Sharpen Method as None, and set Stretch Method on the Enhancement tab to None.
3. Add the NDVI process to the service by opening the Image Service Properties dialog box and clicking the Service Processes node from the list on the left. This displays the interface for adding processes to the service. Add the NDVI process to the selected list and open it using the Edit button . Type 1 in the Red band text box and 2 in the Near-infrared band text box, because when adding the Landsat data to the image service, you defined band 1 as red (3) and band 2 as NIR (4). Next, specify an offset of 50 and leave the scale as 1. The result of this process is a single-band NDVI computation. The next process will enable visualization of this output as an RGB image.
4. Add Colormap to the selected process list and open it using the Edit button . Specify a predefined color table source file.

   You have completed the required process chain and can now close the Image Service Propertiesdialog box.

5. Build the image service definition with the Compute Output Properties options checked, as the output image properties may have changed from an image of two or more bands to a one-band image.
6. Preview the image service.
7. Compile the image service definition.