PDS_VERSION_ID       = PDS3                                                   
RECORD_TYPE          = STREAM                                                 
OBJECT               = TEXT                                                   
  NOTE               = "PDSREAD.TXT file for GEM Data Set Collection Volume"  
  PUBLICATION_DATE   = 1995-12-31                                             
END_OBJECT                                                                    
END                                                                           
                                                                              
***** File PDSREAD.TXT                                                        
                                                                              
PDSREAD was created at the Small Bodies Node (SBN) of the Planetary Data      
System (PDS) to read PDS image and data files. For complete explanations      
regarding the use of any of these programs, check the headers of the program  
source files, which end in '.pro'.                                            
                                                                              
HISTORY: These programs were announced for original test release at the       
November, 1994 meeting of the Planetary Data System, and have been included   
on this CD-ROM for use with any PDS image or table files on this disc or      
elsewhere.  A complete listing of the programs follows:                       
                                                                              
btabvect.pro            -retrieves vectors from PDS binary tables             
headpds.pro             -retrieves the PDS label from a file                  
imagepds.pro            -retrieves image data from PDS image files            
pdspar.pro              -retrieves specified data from PDS labels             
readpds.pro             -calls imagepds, tascpds, and tbinpds, returns data   
str2num.pro             -converts character string to numerical form          
tascpds.pro             -retrieves data from PDS ascii table files            
tbinpds.pro             -retrieves data from PDS binary table files           
                                                                              
NOTE: Additional programs not written at SBN are required to properly access  
binary table data. They are 'conv_vax_unix.pro' and 'ieee_to_host.pro', and   
may be found in NASA/Goddard's IDL Astronomy Users Library ( anonymous ftp    
at idlastro.gsfc.nasa.gov /pub/astron.tar.Z )                                 
                                                                              
COMPATIBILITY WARNINGS: These programs have only been tested on IDL version   
3.6.1 for SunOS and Solaris 2.4, they may not work as well on other           
systems/versions.                                                             
                                                                              
PDS objects supported by these programs                                       
                                                                              
Major Objects:                                                                
                                                                              
IMAGE                                                                         
TABLE                                                                         
INDEX_TABLE                                                                   
GAZETTEER_TABLE                                                               
PALETTE                                                                       
SERIES                                                                        
SPECTRUM                                                                      
TEXT                                                                          
                                                                              
Sub-objects:                                                                  
COLUMN                                                                        
                                                                              
PDS objects not supported by these programs                                   
                                                                              
ARRAY                                                                         
BIT_COLUMN                                                                    
BIT_ELEMENT                                                                   
CATALOG                                                                       
CONTAINER                                                                     
ELEMENT                                                                       
HISTOGRAM                                                                     
HISTORY                                                                       
IMAGE_MAP_PROJECTION                                                          
QUBE                                                                          
SPICE_Kernal                                                                  
                                                                              
PDS objects not needed by these programs                                      
                                                                              
COLLECTION                                                                    
DATA_PRODUCT                                                                  
DATA_SUPPLIER                                                                 
DIRECTORY                                                                     
DOCUMENT                                                                      
FILE                                                                          
HEADER                                                                        
VOLUME                                                                        
                                                                              
============================================================================  
Quick guide for new IDL users:                                                
        To use these functions to view a pds image;                           
1) copy these functions to a directory of your choice,                        
2) make sure you are in a 'windows' type environment (eg; x-windows,          
        MS-Windows,open-windows,etc ) before proceeding,                      
3) at the prompt type:                                                        
                        idl                                                   
        on a unix system, this should bring up a prompt like this : IDL>      
4) at the 'IDL>' prompt, type IDL commands as you would DOS or UNIX           
commands, example:                                                            
                        tvscl, readpds(imgfile)                               
        this should bring up a window with a display of the image inside.     
5) to exit 'IDL' type :                                                       
                        exit                                                  
        this will return you to the normal prompt, and close any idl          
        image windows still open at the time.                                 
============================================================================  
                                                                              
LICENSING INFORMATION:                                                        
IDL is the property of Research Systems, Inc., Copyright 1989-1994            
All rights reserved.  Unauthorized reproduction prohibited.                   
The University of Maryland is licensed to use IDL.