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Diffstat (limited to 'ast/stcschan-demo2.c')
| -rw-r--r-- | ast/stcschan-demo2.c | 263 |
1 files changed, 0 insertions, 263 deletions
diff --git a/ast/stcschan-demo2.c b/ast/stcschan-demo2.c deleted file mode 100644 index 1967e0b..0000000 --- a/ast/stcschan-demo2.c +++ /dev/null @@ -1,263 +0,0 @@ -/* Name: - stcschan-demo2.c - - Purpose: - A demonstration of the facilities provided by the AST library - for reading STC metadata encoded using the STC-S linear string - format. - - Description: - This program reads a set of FITS-WCS headers from a text file, and - writes an STC-S description of the region covered by the FITS - file to standard output. - - Notes: - - The simple approach used in this demonstration will report an - error if the FITS headers describe a WCS in which some pixels have - invalid WCS axis values (such as most all sky maps, for instance). - - Usage: - % stcschan-demo2 <header-file> - - <header-file>: The path to a text file containing a set of FITS-WCS - headers. - - Example: - % stcschan-demo2 m31.head - - To compile and link: - Assuming your starlink distribution is in "/star": - - % gcc -o stcschan-demo2 stcschan-demo2.c -L/star/lib \ - -I/star/include `ast_link` - -*/ - -/* Include system headers. */ -#include <stdio.h> -#include <string.h> - -/* Include the AST library header. */ -#include "ast.h" - -/* Maximum number of axes in an STC-S AstroCoordSystem. */ -#define MAX_AXES 5 - -/* Maximum allowed length for a single line of text from the disk file. */ -#define MAX_LINE_LEN 100 - -/* Prototype for the function that reads text from the disk file. */ -const char *source( void ); - - - -int main( int argc, char **argv ){ - -/* Local variables: */ - AstBox *pixbox; - AstFitsChan *fchan; - AstFrame *pixfrm; - AstFrame *wcsfrm; - AstFrameSet *frameset; - AstKeyMap *warnings; - AstMapping *pix2wcs; - AstObject *object; - AstRegion *wcsbox; - AstStcsChan *schan; - FILE *fd; - char key[ 15 ]; - char keyword[ 9 ]; - const char *message; - double p1[ MAX_AXES ]; - double p2[ MAX_AXES ]; - int axis; - int iwarn; - int naxis; - int status; - -/* Initialised the returned system status to indicate success. */ - status = 0; - -/* Check a file was specified on the command line, and attempt to open it - for read access. */ - if( argc < 2 ) { - printf( "Usage: stcschan-demo2 <header-file>\n" ); - status = 1; - } else { - fd = fopen( argv[ 1 ], "r" ); - if( !fd ) { - printf("Failed to open input file '%s'.\n", argv[ 1 ] ); - status = 1; - } - } - -/* If a disk file was opened successfully... */ - if( !status ) { - -/* Start an AST object context. This means we do not need to annull - each AST Object individually. Instead, all Objects created within - this context will be annulled automatically by the corresponding - invocation of astEnd. */ - astBegin; - -/* Create a FitsChan. This is the object that converts external FITS - headers into corresponding AST Objects. Tell it to use the "source" - function for obtaining lines of text from the disk file. */ - fchan = astFitsChan( source, NULL, " " ); - -/* Associate the descriptor for the input disk file with the StcsChan. - This makes it available to the "source" function. Since this - application is single threaded, we could instead have made "fd" a - global variable, but the ChannelData facility is used here to illustrate - how to pass data to a source or sink function safely in a multi-threaded - application. */ - astPutChannelData( fchan, fd ); - -/* Attempt to read the FITS heades and convert them into an AST FrameSet. */ - object = astRead( fchan ); - -/* The astRead function is a generic function and so returns a generic - AstObject pointer. Check an Object was created successfully. */ - if( !object ) { - printf( "Failed to read an AST Object from file '%s'.\n", - argv[ 1 ] ); - status = 1; - -/* Now check that the object read is actually an AST FrameSet, rather than - some other class of AST Object. */ - } else if( !astIsAFrameSet( object ) ) { - printf( "Expected a FrameSet but read a %s from file '%s'.\n", - astGetC( object, "Class" ), argv[ 1 ] ); - status = 1; - -/* We now know we have a FrameSet so it is safe to use the pointer - returned by astRead as a FrameSet pointer. Do the cast now to avoid - repeated casting in future. */ - } else { - frameset = (AstFrameSet *) object; - -/* Get a pointer to the Frame that describes the attributes of the FITS - world coordinate system. This is the current Frame in the FrameSet - read from the FITS headers. */ - wcsfrm = astGetFrame( frameset, AST__CURRENT ); - -/* Get a pointer to the Frame that describes the attributes of the FITS - pixel coordinate system. This is the base Frame in the FrameSet - read from the FITS headers. */ - pixfrm = astGetFrame( frameset, AST__BASE ); - -/* Get the Mapping that transforms pixel positions into WCS positions. - The is the Mapping from base to current Frame in the FrameSet read - from the FITS headers. */ - pix2wcs = astGetMapping( frameset, AST__BASE, AST__CURRENT ); - -/* Get the number of axes in ther pixel Frame. */ - naxis = astGetI( pixfrm, "Naxes" ); - -/* For each pixel axis, form the name of the corresponding NAXISi - keyword. */ - for( axis = 0; axis < naxis; axis++ ) { - sprintf( keyword, "NAXIS%d", axis + 1 ); - -/* Store the pixel coordinate on the current axis at the lower left corner - of the first pixel. */ - p1[ axis ] = 0.5; - -/* Get the NAXISi value for the current axis from the FITS header, and - store it in array "p2". Report an error if NAXISi is not found. */ - if( !astGetFitsF( fchan, keyword, p2 + axis ) ){ - printf("Keyword '%s' not found in header\n", keyword ); - status = 1; - break; - -/* If it is found, modify "p2" so that it holds the pixel coordinate on - the current axis at the upper right corner of the last pixel. */ - } else { - p2[ axis ] += 0.5; - } - } - } - -/* If all has gone well, create an AST Region (a Box) describing the - rectangular region of pixel coordinates covered by the pixel array. */ - if( !status ) { - pixbox = astBox( pixfrm, 1, p1, p2, NULL, " " ); - -/* Map this box into the FITS world coordinate system. The Mapping is - specified by "pix2wcs", and the attributes of the resulting axes is - described by "wcsfrm". */ - wcsbox = astMapRegion( pixbox, pix2wcs, wcsfrm ); - -/* Create an StcsChan. This is the object that converts (either way) - between external STC-S descriptions and their corresponding AST Objects. - Tell it to use the "source" function for obtaining lines of text from - the disk file. Also tell it to store all warnings generated by the - conversion for later use. Other attributes of the StcsChan class retain - their default values. */ - schan = astStcsChan( NULL, NULL, "ReportLevel=3" ); - -/* Attempt to write out the Region describing the pixel array (in WCS) - as an STC-S description. Report an error if this fails. */ - if( ! astWrite( schan, wcsbox ) && astOK ) { - printf( "Failed to convert the Region into an STC-S " - "description.\n" ); - } - } - -/* We asked the StcsChan to record any warnings that were generated - whilst converting the AST Region into a corresponding STC-S description. - We now see if any such warnings were generated by the earlier call to - astWrite. */ - warnings = astWarnings( schan ); - -/* If any warnings were generated, and if no other error has occurred so - far, display the warnings. */ - if( warnings && !status && astOK ) { - printf( "\nThe following warnings were issued:\n" ); - -/* The warnings are stored in an AST KeyMap (a sort of hashmap). Each - warning message is associated with a key of the form "Warning_1", - "Warning_2", etc. Loop round successive keys, obtaining a value for - each key from the warnings KeyMap, and displaying it. */ - iwarn = 1; - while( astOK ) { - sprintf( key, "Warning_%d", iwarn++ ); - if( astMapGet0C( warnings, key, &message ) ) { - printf( "\n- %s\n", message ); - } else { - break; - } - } - } - -/* End the AST Object context. All Objects created since the - corresponding invocation of astbegin will be annulled automatically. */ - astEnd; - -/* Close the disk file. */ - (void) fclose( fd ); - } - -/* If an error occurred in the AST library, set the retiurns system - status non-zero. */ - if( !astOK ) status = 1; - return status; -} - - - - - -/* This is a function that reads a line of text from the disk file and - returns it to the AST library. It is called from within the astRead - function. */ -const char *source( void ){ - static char buffer[ MAX_LINE_LEN + 2 ]; - FILE *fd = astChannelData; - return fgets( buffer, MAX_LINE_LEN + 2, fd ); -} - - - - - |