IMERG GeoTIFF + Worldfile Documentation
NASA produces a GIS translation of IMERG for various accumulation periods that maintains the 0.1-degree resolution and global coverage of the original HDF5 data product. In April 2019, Version 6 of IMERG was released in both the HDF5 and the GIS formats. Version 6 is the first version to cover the approximately 20-year period from June 2000 to the present. This long-duration archive will be a boon to scientific research and will provide an expanded training set for realtime applications such as disaster monitoring.
The purpose of this document is to describe the Geographic Information System (GIS) translation of the IMERG data product, hereafter referred to as "IMERG GIS." IMERG GIS is essentially a data file containing two-byte integer data stored as a Georeferenced Tagged Image File Format (GeoTIFF) file. A GeoTIFF file contain geographic metadata, but PPS also stores the same the geographic metadata in a separate Environmental Systems Research Institute (ESRI) WorldFile, a human readable text file. The WorldFile is for the use of GIS applications that are unable to read the geographic metadata that is stored inside of a GeoTIFF file