Many of the options available to you in GeoExpress vary depending on the output format that you select. Additionally, the options available depend on whether the file is a raster file or a LiDAR point cloud file.
GeoExpress supports the following output formats:
The MrSID format is a proprietary format developed by LizardTech that supports lossy and lossless compression. There are several generations of the MrSID file format. Additionally, for the latest generation, MrSID Generation 4 (MG4), there is a version that supports raster and a version that supports LiDAR.
The raster version of MG4 supports multispectral data, per-band compression, custom metadata, and advanced image manipulation features. The format is widely supported across GIS software packages. The LiDAR version of MG4 stores compressed point clouds in an accessible format meant to address some of the problems with storing and accessing large LiDAR point clouds.
For both raster and LiDAR data, if you're not sure which file format to select, you may want to select MrSID Generation 4.
The JPEG 2000 format is an open standard that provides superior compression compared to the original JPEG format.The JPEG 2000 (Part I) format uses the original JPEG 2000 specification which is more widely supported. The JPEG 2000 (GMLJP2) format includes support for geographic markup language (GML). Use the JPEG 2000 (GMLJP2) format when you need to create JPEG 2000 files that contain coordinate reference systems (CRS), topology, and other geographic features.
For a comparison of MrSID and JPEG 2000 files, see Comparison of Compressed Output Formats.
The NITF format is a container that can include an image, image metadata, and other graphics. GeoExpress supports creating NITF files that contain raw or JPEG 2000 images.The NITF format is the standard for various departments of the United States government. Use the NITF format when your organization requires NITF metadata.
The GeoTIFF format embeds georeferencing metadata into TIFF images. In GeoExpress, you can only create GeoTIFF files from MrSID input files, and you can only create uncompressed GeoTIFF files. Use the GeoTIFF format when you might need to view your image in an image viewer that does not support GIS. Any image viewer that can read TIFF files will display GeoTIFF images. If the viewer does not support the georeferencing metadata, the metadata is ignored. GeoTIFF is generally an uncompressed file format.
The LAS format is one of the most commonly used LiDAR file formats, and can be read in virtually any application that support LiDAR point clouds. LAS is a public, uncompressed file format maintained by the American Society for Photogrammetry and Remote Sensing (ASPRS). GeoExpress can write LAS 1.0 through 1.4 files.
When you create a LAS file from another LAS file, GeoExpress uses the same version of LAS. For example, if the input file is a LAS 1.1 file, GeoExpress creates another LAS 1.1 file. If you write a LAS file from MrSID or from another format, the version of LAS that GeoExpress uses depends on the contents of the file. If the file contains features unique to a specific version of LAS, GeoExpress uses that particular version.
The LAZ format is a compressed format for LiDAR point clouds. LAZ is an open-source file format developed by Martin Isenberg at RapidLasso.
GeoExpress does not support LAZ output from a LAS 1.4 file that includes records 6–10.
Binary Point File (BPF) serves as a lightweight, quick, binary file format for the storage of unorganized point cloud data. It is commonly used in Geiger Mode LiDAR imagery.