Software and Data Mosaic datasets resolve many traditional raster management issues By Colin Childs, Esri Education Services Mosaic dataset Source images Sources, mosaic methods, and functions are used when creating a mosaic dataset. On-the-fly processing generates mosaicked images on demand. Mosaicked images Catalog ArcGIS 10 introduces a powerful and exciting new geodatabase data model for managing raster data that reduces processing time; maintains information from overlapping imagery; and easily handles large, disparate datasets. The mosaic dataset allows you to catalog collections of raster and image data as well as define and refine the metadata and processing applied to this data. These collections can range in size from a few rasters to collections that are large both in terms of total file size and in the number of raster datasets participating in the mosaic. Mosaic datasets can be directly accessed by users of ArcGIS Desktop or served as an image service to many users. Mosaic datasets are accessed as dynamically mosaicked images that can be controlled and refined by the end user, making all information content in the imagery accessible. www.esri.com Dynamic Mosaicking The mosaic dataset references the original pixels and stores detailed properties, metadata, and processing information about the imagery and references the original pixels. It can be stored in any geodatabase (file or ArcSDE) and is part of core ArcGIS 10 software. Although mosaic datasets can be accessed and viewed in ArcGIS with any license level, an ArcEditor or ArcInfo license is required to create or edit them. Serving mosaic datasets with ArcGIS Server requires the Image extension license. Creating and managing a mosaic dataset follows a simple workflow that uses geoprocessing tools for creation and management and ArcMap for interactive editing and display. In addition, geoprocessing models and Python may be used to automate and manage mosaic datasets. Raster data is added directly to a mosaic dataset, and the properties are stored in the geodatabase. By specifying a raster type, data can be directly incorporated from sensors or files that include detailed properties such as spatial reference metadata, acquisition dates, and sensor type as well as defined optional details for additional processing such as orthorectification. Note that raster datasets in a mosaic dataset can remain in their native format on disk or may be loaded into the geodatabase (if required). Continued on page 8 ArcUser Summer 2010 7