# PHOTOMOD Raster File

PRF or MegaTIFF is an internal format of PHOTOMOD software for storing large images.

This format was developed to store images larger than 4 GB. As a basis for storing data used TIFF or JPEG2000 format. Raster is split into fragments (tiles) such that each fragment does not exceeded a predefined size (e.g., less than 1 GB). An overview file also added to process raster data on a small scales.

PRF files has two variations: 'prf' for imagery data and 'x-dem' for elevation data. Files can be georeferenced, but projection information can be stored only in external files (*.prj).

Image format has the following structure:

- the header XML file 'image_name.prf'/'image_name.x-dem'
- folder 'image_name' with raster subtiles
- files *.tif/*.jp2/*.demtif inside folder 'image_name', containing raster fragments and the overview image

The driver support the data type among Byte, UInt16, UInt32, Float32 or Float64.

## See Also

- Racurs company home page
- PHOTOMOD Lite home page