Files containing GOES map outlines and navigation information  
(latitude and longitude) are stored in this directory.
The time-stamp that is encoded in each file name is the time of the  
raw GVAR file that the navigation was generated from.
Since the GOES satellite is geostationary, the map and navigation  
files should in general be valid for many months.



1. The postscript files (those with the "ps" suffix) are high  
resolution vector map images.
There are up to 3 files of this type:

1 - Files ending with "countries.ps" are country borders.
2 - Files ending with "coasts.ps" are shorelines.
3 - Files ending with "states.ps" are United States state boundaries.

For sectors that do not show any parts of the US, the state file will  
not be present.

The state and country boundaries are plotted from shapefiles  
distributed with IDL, while the coastlines are from GSHHS (http:// 
www.soest.hawaii.edu/wessel/gshhs/gshhs.html)

The postscript files containing "I01" match the visible image files  
in size, while those containing "I04" match the infrared image files.




2. The TIFF files have been generated from the postscript files using  
the ghostscript "gs" program (http://pages.cs.wisc.edu/~ghost/).

The command used is:

gs -sDEVICE=tiff24nc -dGraphicsAlphaBits=4 -dSAFER -dBATCH -dNOPAUSE - 
q -sOutputFile=xxx.map xxx.ps

After the TIFF raster image files have been created, they are  
internally LZW-compressed, as are the GOES ".tif" images.




3. The navigation files (those ending with "nav.gz") contain latitude/ 
longitude data for each pixel in the GOES images.

The files have been compressed with "gzip" (http://www.gzip.org/).
The files are binary format, and are either 4-byte float or 2-byte  
integer.
Two versions of each are provided; the ones labeled with an "M" are  
in MSBF byte order, and those labeled with "L" are in LSBF byte order.


The 2-byte integer files start with 2 4-byte integer values giving  
the pixel and line (x,y) size of the file.
The 4-byte float files have no header giving the array size, they  
simply have the lat/long data.
People using the float navigation files can find the x and y  
dimensions from the matching visible or infrared channel maps or images.

The data part of the files consists of lat/long value-pairs start in  
the upper left-hand (northwest) corner of each image, and proceed to  
the right (east).



The 2-byte integer files have succeeding pairs of elements are 2-byte  
integer values of latitude and longitude multiplied 100 and truncated  
(e.g. 75.324 E is "-7532").
The 4-byte float files have succeeding pairs of elements are 4-byte  
float values of latitude and longitude.