GeoExpress can create raster mosaics in the MrSID format, the JPEG 2000 format, and the NITF format. GeoExpress can create LiDAR mosaics in the MrSID Generation 4 and LAZ formats.
If you create a mosaic from existing MrSID images or JPEG 2000 images, GeoExpress does not deduct data from the data cartridge. Additionally, if you create a mosaic from NITF files that contain JPEG 2000 images, GeoExpress does not deduct data from the data cartridge. For more information on output formats, see Supported Output Formats.
Use the MrSID file format to create flat mosaics and composite mosaics. A flat mosaic is a single image that you create from multiple input images. A composite mosaic is a group of images that display as a single image.
When you create a flat mosaic, GeoExpress creates a single image from the input tiles. Because a flat mosaic is a single image, it displays more quickly than a composite mosaic. You can perform any image manipulation operation on a flat mosaic that you can perform on a single image.
When you create a composite mosaic, GeoExpress creates a MrSID file that contains multiple input tiles. You can only create composite mosaics out of input tiles in the MrSID format. To create a composite mosaic out of images in other formats, first convert the input images to the MrSID format, then create a mosaic out of the MrSID files.
Because a composite mosaic is a container for existing files, you can create a composite mosaic without running an encoding operation. Use composite mosaics when you want to create mosaics quickly, for example, when you want to create mosaics from large input tiles.
A composite mosaic in the MrSID Generation 4 (MG4) format can only contain MG4 input tiles. A composite mosaic in the MrSID Generation 3 (MG3) format can contain MG3 and MG2 input tiles.
An MG4 composite mosaic contains an overview image for viewing at low resolutions. As a result, MG4 composite mosaics display more quickly than MG3 composite mosaics. However, MG4 composite mosaics may take slightly longer to create.
When you create mosaics in the JPEG 2000 format, GeoExpress runs an encoding operation that creates a single image from the input tiles. JPEG 2000 mosaics are equivalent to flat MrSID mosaics.
Use the NITF file format to create mosaics with single or multiple image segments. An image segment is an image in a NITF file. When you create a mosaic in the NITF file format, you can combine the input tiles into a single image or you can add each image to the NITF file separately. If you add images to the NITF file separately, the mosaic is called a multiple image segment mosaic. If you combine the input images into a single image, the mosaic is called a single image segment mosaic. A mosaic made up of a single image segment is equivalent to a flat MrSID mosaic. A mosaic with multiple image segments is similar to a composite mosaic in that it preserves the information from each input tile. However, multiple image segment mosaics require an encoding operation unlike composite mosaics, therefore they take longer to create.