About importing or loading raster data

Whether you create a new geodatabase or are working with an existing one, you will most likely need to import (load) some data. Importing data allows you to take existing data and make it available for use within a geodatabase.

There are three raster storage mechanisms in a geodatabase:

• Raster datasets—You can store many raster datasets in a geodatabase, or mosaic all your rasters into a single raster dataset. Importing rasters to a raster dataset will add the raster dataset into an empty raster dataset or mosaic it with a raster dataset that is already present.
• Raster catalogs—You can store the rasters within the catalog (managed) or store a link to the source rasters that you can store elsewhere (unmanaged). Importing a raster dataset into a raster catalog will add the raster dataset to the raster catalog as a new raster catalog item, or you can choose to mosaic it into an existing raster catalog item.
• Mosaic datasets—These are designed to manage the access to your raster data collections. When you add raster data to a mosaic dataset, the raster data is not stored within the mosaic dataset, but a link to the source raster is stored. Additionally you can add functions to perform on-the-fly processing.

Raster data can be imported into a geodatabase in several ways: by using Import raster datasets (geodatabase context menu), the Copy Raster tool (geoprocessing tools), or Load Data (ArcCatalog dataset context menu).