Defining or adding derived tiles

步骤：

1. Click the New Rectangle , New Polygon , New Circle , or New Ellipse tool on the Draw toolbar.
2. Draw a polygon over the area in the service where you want to generate derived raster tiles.

   提示:

   • If you have more than one polygon graphic in the display view, use the Select tool to choose the polygon graphic from which you want to generate the derived raster tiles.
   • You can use the Select tool to select more than one polygon graphic by holding the SHIFT key while clicking to select a graphic.

3. Click the Image Service drop-down menu on the Image Service Definition Editor toolbar and click Advanced > Optimize > Derived Tiles > Define.

   The Derived Tiles Options dialog box appears.

4. The following fields on the dialog box need to be filled in:

   Pixel Size	Pixel size used to create the derived tiles.
   Optimum Number of Rows	Optimum number of rows in the derived tile. The larger the value, the bigger the file and the more likely that it will need to be regenerated if any lower image changes. More files are created if the value is small.
   Optimum Number of Cols	Optimum number of columns in the derived tile. The larger the value, the bigger the file and the more likely that it will need to be regenerated if any lower image changes. More files are created if the value is small.
   Derived Images Output Folder	Folder to which the derived tiles are output. If undefined, these images will be placed in a folder with the same name as the service definition folder but with the extension .DerivedImages.
   Sampling Method	Sampling method to be used to create service overviews.
   Format	Format to be used to create external overviews. 注： The JPEG 2000 format cannot be used to write files that are 32- or 64-bit.
   Compression Method	Method of compression to be used to create external overviews.
   Compression Quality	Compression quality to be used to create external overviews.
   Tile Size	Tile size that has to be used (for TIFF) to create external overviews.

5. Click OK.

   The derived tiles, covering the defined area, are created and added to the service definition.

6. Click the Service Table button on the Image Service Definition Editor toolbar. You can view the details of the derived tiles in the bottommost rows of the table.

To create the derived tiles, you need to build the image service definition by checking the Generate derived images option on the Build Options dialog box.