How raster data is stored and managed

A mosaic dataset is a collection of raster datasets (images) stored as a catalog and viewed or accessed as a single mosaicked image or individual images (rasters). These collections can be extremely large in both total file size and number of datasets. The raster datasets in a mosaic dataset can remain in their native format on disk or exist in the geodatabase. The metadata can be managed within the raster's record as well as attributes in the attribute table. Storing metadata as attributes enables parameters such as sensor orientation data to be managed more easily and allows fast queries to enable selections.

Individual rasters and metadata comprise mosaic datasets.

The data in a mosaic dataset does not have to be adjoining or overlapping but can exist as unconnected, discontinuous datasets. For example, you can have images that completely cover an area, or you can have many strips of images that may not join together to form a continuous image (such as along pipelines).Continuous data coverageDiscontinuous data coverage

The data can even be completely or partially overlapping but captured over different dates. The mosaic dataset is an ideal dataset for storing temporal data. You can query the mosaic dataset for the images you need based on time or date and use a mosaic method to display the mosaicked image according to a time or date attribute.

Mosaic datasets are not limited to one particular type of raster data. You can add raster data from different sensor systems in different projections, resolutions, pixel depths, and numbers of bands. Overviews (like pyramids) can be generated for the entire data collection. This allows for faster viewing of the data and allows you to quickly serve these datasets. There are also many additional properties for viewing, including setting a mosaicking method, that make these datasets unique and functional in many situations. You can also query a mosaic dataset based on your spatial and nonspatial query constraints. The results of that query could be a set of images that you can process one by one, or it could be a dynamically generated mosaicked image.

In addition to raster data, you can store and manage lidar data in a mosaic dataset in the same way as raster datasets and even together with raster datasets. The lidar data can be stored in the file system as LAS files or LAS datasets, or in a geodatabase as a terrain dataset.

Mosaic dataset are dependent on the version of ArcGIS on which they were built, and are compatible across the ArcGIS platform for a particular release cycle. In general, mosaic datasets created with older versions of ArcGIS can be read and handled with newer versions of ArcGIS. However, a mosaic dataset created with a newer version of ArcGIS may not be backwards compatible with older versions. See the table below for mosaic dataset compatibility:

Learn more about the mosaic dataset