# HFA -- Erdas Imagine .img

GDAL supports Erdas Imagine .img format for read access and write. The current implementation ignores pyramid levels, and metadata but does capture palettes, and georeferencing. It supports the erdas band types u8, s8, u16, s16, u32, s32, f32, f64, c64 and c128.

Compressed and missing tiles in Erdas files should be handled properly on read. Files between 2GB and 4GB in size should work on Windows NT, and may work on some Unix platforms.

Metadata reading and writing is supported at the dataset level, and for bands, but this is GDAL specific metadata - not metadata in an Imagine recognised form. The metadata is stored in a table called GDAL_MetaData with each column being a metadata item. The title is the key and the row 1 value is the value.

## Creation Issues

Erdas Imagine files can be created with any GDAL defined band type, including the complex types. Created files may have any number of bands. Pseudo-Color tables will be written if using the GDALDriver::CreateCopy() methodology. Most projections should be supported though translation of unusual datums (other than WGS84, WGS72, NAD83, and NAD27) may be problematic.

Creation Options:

- There are no creation options for Erdas Imagine files at this time.

Erdas Imagine supports external creation of overviews (with gdaladdo for instance).

See Also:

- Implemented as `gdal/frmts/hfa/hfadataset.cpp`.

- More information, and other tools are available on the Imagine (.img) Reader page.

- Erdas.com