Image Navigation Record
This header is one of the most interesting things you can get. It is used to map a specific pixel to a coordinate (latitude / longitude) in the image (and vice-versa). This header is not mandatory on any of the images, and some satellite relays doesn't include it. For example Himawari 8 relays over GOES-16 doesn't include Navigation Record. Open Satellite Project uses this header to generate Map Overlays and to define the coordinate of the center of the image (useful for non full disk scans).
| Name | Type | Description |
|---|---|---|
| Projection Name | string ( 32 ) | The name of the Image Projection |
| Column Scaling Factor | uint32_t | The Scaling Factor for each column |
| Line Scaling Factor | uint32_t | The Scaling Factor for each line |
| Column Offset | uint32_t | The Offset for Columns |
| Line Offset | uint32_t | The Offset for Lines |
Table 7 - Image Navigation Record Fields
For calculation of the Lat/Lon Coordinates a mathematical model described in CGMS 03 - LRIT/HRIT Global Specification (page 20) should be used. A pratical implementation can be found on Open Satellite Project GeoTools Class.