Recomputing footprints based on geometry

Recomputing footprints by geometry redefines a footprint for each raster dataset by considering the warping applied to the pixels as they are georeferenced. For rasters that are georeferenced with no rotation, this process is equivalent to determining the envelope and can be used to reset the extents. This feature is very helpful, especially when you have raster datasets with complex georeferencing, as it can accurately determine the edges and therefore eliminate slivers that may appear along their edges in undulating terrain. It should also be run on raster datasets if their georeferencing has been changed.

Recomputing footprints by geometry is calculated at the raster level by transforming a set of points along the edge of the raster dataset from the raster coordinate system into the ground coordinate system through the different transformations and projections that may be applied. The vertices of the footprint polygon are projected into the image service spatial reference system. This operation is based only on the geometry of the pixels. Processes that affect the radiometry of the service have no effect on the results.

The Recompute Footprint By Geometry dialog box has two tabs: General and Advanced. The following image type options are provided on the General tab. The option you choose in the General Tab updates parameters in the Advanced tab that are used by this process.

Using the Advanced tab, you can view or set the following parameters:

步骤:
  1. Open an existing image service definition or use one that is already open in ArcMap.
  2. Right-click the Footprint layer in the table of contents and click Recompute Footprint > By Geometry.

    The Recompute Footprint By Geometry dialog box is displayed with default values for each of the parameters.

  3. Click the Image type drop-down arrow and click one of the options.
  4. Optionally, click the Advanced tab and make changes to the parameters.
  5. Click OK.

7/10/2012