Creating a mosaic dataset

This topic applies to ArcEditor and ArcInfo only.

When you create a new mosaic dataset, an empty schema is defined in the geodatabase with some default properties to which you can add raster data.

To create the mosaic dataset, you can right-click the geodatabase in ArcCatalog or the Catalog window and select New > Mosaic Dataset. This will open the Create Mosaic Dataset tool. Or you can directly access and open the Create Mosaic Dataset tool from the Search window or ArcToolbox window.

When you create a new mosaic dataset, it is created in a geodatabase, so you must have write access to that geodatabase and an ArcEditor or ArcInfo license. You also need to specify a name and a spatial reference. The spatial reference does not need to match the raster data you are adding; however, it will be used to create any of the additional components, such as the boundary and footprints. It will also be the default spatial reference of the mosaic dataset when it is accessed, therefore, any raster datasets in a different spatial reference will be reprojected but only when they are used to create the mosaicked image.


If the spatial reference systems of the data and the mosaic dataset or user are based on different spheroids you may need to specify a specific geographic transformation. You can specify the transformation in two location. When adding imagery to the mosaic dataset that has a different datum than the mosaic dataset, set the Geographic Transformation on the Environment Settings dialog box. If you know the user or application will be using a different datum than the source imagery or mosaic dataset, open the mosaic dataset properties (via ArcCatalog or the Catalog window) and click the Defaults tab, then set the Geographic Coordinate System Transformation property.

You can also define the number of bands that will be output from the mosaic dataset and the output pixel type, but it's not necessary to define these options. By default, this information will be derived from the first raster added or altered as functions are defined that require the defaults to be defined. If you're mixing the types of raster data used in the mosaic dataset, it is recommended that you define these values. For example, if using raster data from single-band orthophotos and multiband satellite images, and you want to see them both, you need to specify three bands or more, otherwise it will default to the properties of the first image added (which may be your single-band orthophoto).

Use the Add Rasters To Mosaic Dataset tool to add raster data to the mosaic dataset.

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