USDA ARS

IPW Image Headers

In addition to the pixel data, an IPW image file also contains information about the attributes of the pixel data as well as the image itself. This ancilliary information is stored in the image's headers. As their name implies, headers are stored at the beginning of the image file, i.e., the top or "head" of the file.

Basic Image Header

There are several types of headers. Each IPW image has a basic image (BI) header which describes the dimensions of the image:

The BI header also contains basic information about each band in the image: The BI header for an IPW image is created using the IPW command mkbih.

Optional Header Types

Besides the BI header, there are several types of optional headers which are listed in the table below. Each optional header in an IPW image is associated with a particular band in the image. Like the BI header, each type of optional header has a corresponding IPW command for creating that type of header.

Header type Description IPW command
LQ linear quantization parameters for pixel data mklqh
GEO geographic information for an image mkgeoh
WIN coordinates of a window (subregion) of an image mkwinh
CR range information for classes of pixel data mkcrh
SUN sun position information mksunh
SAT satellite parameters mksath


IPW documentation / Last revised 20 May 2009 / IPW web site