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:
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 |