GINI Format for AWIPS Satellite Data
GINI Overview
The GINI product is broken down into two subsections:
1. Product Definition Block
The product definition block is a 512 byte block which describes the image data.
| Octet/Byte | Description |
|---|---|
| 01 | Source - 1=NESDIS |
| 02 | Creating entity |
| 03 | Sector identifier |
| 04 | Physical element |
| 05-06 | Number of logical records (scan lines) |
| 07-08 | Size of logical record (pixels per scan line) |
| 09 | Valid Time - Year of century |
| 10 | Month |
| 11 | Day |
| 12 | Hour |
| 13 | Minute |
| 14 | Seconds |
| 15 | Hundredths of seconds |
| 16 | Map projection indicator |
| 17-41 | Projection Definition (see below) |
| 42 | Image resolution |
| 43 | Data compression indicator (1=compressed, 0=no compression) |
| 44 | Version of PDB |
| 45-46 | Size of PDB in bytes |
| 47 | Navigation/Calibration indicator (0=nav/cal not included, 1=nav/cal included, 2=nav only, 3=cal only) |
| 48-512 | Reserved |
2. Projection Definition
This section describes the parameters needed to define the projection of the image.
2.1 Projection Definition for Polar Stereographic and Lambert Conformal Images
| Octet | CONTENT & MEANING |
|---|---|
| 16 |
Projection indicator (3=Lambert
Conformal, 5=Polar Stereographic) |
| 17-18 | Nx - Number of points along x-axis |
| 19-20 | Ny - Number of points along y-axis |
| 21-23 | La1 - Latitude of first grid point |
| 24-26 | Lo1 - Longitude of first grid point |
| 27 | Reserved - currently 0 |
| 28-30 | Lov - The orientation of the grid; i.e., the east longitude value of the meridian which is parallel to the y-axis (or columns of the grid) along which latitude increases as the y-coordinate increases. (Note: The orientation longitude may, or may not, appear within a particular grid.) |
| 31-33 | Dx - the X-direction increment (see note 2) |
| 34-36 | Dy - the Y-direction increment (see note 2) |
| 37 | Projection center flag (see note 5) |
| 38 | Scanning mode |
| 39-41 | Latin - The latitude at which the Lambert Conformal projection is tangent to the earth. Set to 0 for stereographic projections. |
Notes:
- Latitude and longitude are in 10-4 (ten-thousandths)
- Increments are in units of tenths of meters, at the tangent latitude (60 degree for stereographic) circle nearest to the pole in the projection plane.
- Latitude values are limited to the range 0 - 900,000. Bit 1 is set to 1 to indicate south latitude.
- Longitude values are limited to the range 0 - 3,600,000. Bit one is set to 1 to indicate west longitude.
- Projection Center Flag -
Bit 1 set to 0 if the North pole is on the projection plane.
Bit 1 set to 1 if the South pole is on the projection plane.
2.4 Grid Definition for Mercator Grids
| Octet | CONTENT & MEANING |
|---|---|
| 16 |
Projection indicator (1=Mercator) |
| 17-18 | Nx - Number of points along a latitude circle |
| 19-20 | Ny - Number of points along a longitude meridian |
| 21-23 | La1 - Latitude of first grid point |
| 24-26 | Lo1 - Longitude of first grid point |
| 27 | Resolution flag Bit 1 = 0 - Direction increments not given, 1 - Direction increments given |
| 28-30 | La2 - latitude of last grid point |
| 31-33 | Lo2 - longitude of last grid point |
| 34-35 | Di - the longitudinal direction increment (see note 2) |
| 36-37 | Dj - the latitudinal direction increment (see note 2) |
| 38 | Scanning mode |
| 39-41 | Latin - The latitude(s) at which the Mercator projection cylinder intersects the earth. |
Notes:
- Latitude and longitude are in 10-4 (ten-thousandths)
- Set to 0
- Latitude values are limited to the range 0 - 900,000. Bit 1 is set to 1 to indicate south latitude.
- Longitude values are limited to the range 0 - 3,600,000. Bit one is set to 1 to indicate west longitude.
- The latitude and longitude of the last grid point should always be given.
3. Image Data Section
This section contains the binary image data. All image values/pixels are 8 bit values organized by scanline. The scan mode determines the order in which each value is placed in the IDS.
A.Creating Entity
| Value | Contents |
|---|---|
| 07 | DMSP |
| 08 | GMS |
| 09 | Meteosat |
| 10 | GOES-7 |
| 11 | GOES-8 |
| 12 | GOES-9 |
| 13 | GOES-10 |
| 14 | GOES-11 |
| 15 | GOES-12 |
B. Sector Identifier
| Value | |
|---|---|
| 0 | Northern hemisphere composite |
| 1 | Eastern CONUS |
| 2 | Western CONUS |
| 3 | Alaska regional |
| 4 | Alaska national |
| 5 | Hawaii regional |
| 6 | Hawaii national |
| 7 | Puerto Rico regional |
| 8 | Puerto Rico national |
| 9 | Supernational composite |
C. Physical Element
| Value | |
|---|---|
| 1 | Visible |
| 2 | 3.9 micron IR |
| 3 | 6.7 micron IR (water vapor) |
| 4 | 11 micron IR (traditional IR) |
| 5 | 12 micron IR |
| 6 | Derived #1 |
| 7 | Derived #2 |
| 8 | Derived #3 |
| 9 | Derived #4 |
D. Scanning Mode Flag
| BIT | VALUE | MEANING |
|---|---|---|
| 1 | 0 | Points scan in +i direction |
| 1 | Points scan in -i direction | |
| 2 | 0 | Points scan in -j direction |
| 1 | Points scan in +j direction | |
| 3 | 0 | Adjacent points in i direction are consecutive (FORTRAN: (I,J)) |
| 1 | Adjacent points in j direction are consecutive (FORTRAN: (J,I)) |
Note: i direction is defined as west to east along a parallel of latitude, or left to right along an x axis. j direction is defined as south to north along a meridian of longitude, or bottom to top along a y axis.