Adding tiled raster types

Often, there are large datasets consisting of raster data that has been premosaicked and cut into many regularly sized, tiled files. Examples of tiled raster datasets include USGS scanned topographic maps, USGS digital orthophoto quadrangles (DOQs), and caches created by some imagery providers. These types of raster datasets can be handled in ArcGIS Image Server using one record per tile; however, this can result in image service definitions with a very large number of records, which can be slow to compile and manage. The tiled raster enables large numbers of rasters to be referenced by a single record in the source table. Tiled rasters can substantially speed up the addition and simplify the management of such datasets.

Tiled rasters are raster datasets that have been clipped to a grid, such as map sheets. To add raster data using a tiled raster, the imagery must be structured into a grid of images where each raster dataset is contained within only one tile. The tiles can be butt joined or overlap. Partial tiles that do not cover the full extent are also allowed. It is assumed that the pixels are aligned. For example, the location of each pixel can be defined by an equation, such as X = BaseX + NX * PixelSizeX, Y = BaseY + NY * PixelSizeY. When adding a tiled raster type, a data structure is created that defines the relationship of each raster dataset to a grid.

When using tiled rasters, only one set of metadata can be defined for the group of tiled raster datasets, and processes cannot be applied to the individual images.

You can add raster datasets as tiled rasters from within the Georeferenced Imagery or Elevation raster types folders when choosing the raster type upon adding the data. The tiled raster types exist within the Select Raster Types dialog box folders. For example, the tiled raster type for TIFF files is contained in the Georeferenced Imagery > Tiled Raster subfolder. The format of these raster datasets can be any of the standard formats that ArcGIS Image Server supports.

When choosing the tiled raster, a dialog box appears so you can choose the folder location of the data, then a dialog box containing the General and Enhancement tabs. The General tab will list parameters specific to that particular raster type and will include the following parameters:

• Spatial reference—Spatial reference of the raster datasets. If undefined, the spatial reference will be obtained from the first raster dataset. If the spatial reference of the raster dataset is undefined, it will be assumed to be the same as that of the image service definition.
• Upper-left X—X-coordinate of the center of the upper left pixel of the most upper left tile. This parameter can be left blank.
• Upper-left Y—Y-coordinate of the center of the upper left pixel of the most upper left tile. This parameter can be left blank.
• Tile spacing X—Spacing in ground units between the tiles, in the x-dimension. This parameter can be left blank.
• Tile spacing Y—Spacing in ground units between the tiles, in the y-dimension. This parameter can be left blank.
• Pixel size X—Pixel size in ground units for all the pixels, in the x-dimension. This parameter can be left blank.
• Pixel size Y—Pixel size in ground units for all the pixels, in the y-dimension. This parameter can be left blank.
• Tiles are of the same size—Optionally, check if the tiles are the same dimension.

If any of the values above are left blank, the software will attempt to determine them. If they are known, it is advantageous to define them.

If there is a missing tile, it will not automatically be removed from the footprint. In other words, there will not be a hole in the footprint polygon where the tile is missing. It is assumed that all the tiles are present. When viewing the image service, the missing area will be represented by the background color defined in the image service definition properties. You can manually edit the footprint, using the editing tools in ArcMap, to clip out the missing tile area within the footprint polygon. Be sure to recalculate the boundary after altering the footprint.

The Enhancement tab contains the parameters commonly found on the Enhancement tab for all raster types.

Learn about the Enhancement tab