Possible design of an editable plaintext table containing WCS information

Here follows a draft schematic for the contents of the FITS header:

TableName: DEI_WCS

TableTypes: CCDPOS AMPPOS CTYPE CRPIX CRVAL CDELT PC CUNIT \
RADECSYS EQUINOX MJD_WCS DOMAIN PROJP

ROW: 1 1 { RA---TAN DEC--TAN } { 1. 1. } { 180. 45. } { 0.0001 0.0001 } \
{ 1. 0. 0. 1. } { deg deg } FK5 2000.0 { } FITS_PIX { }

ROW: 1 1 { RA---TAN DEC--TAN } { 1. 1. } { 180. 45. } { 0.0001 0.0001 } \
{ 1. 0. 0. 1. } { deg deg } GAPPT { } 50283.00 FITS_PIX { }

ROW: 1 1 { RA---SIN DEC--SIN } { 1. 1. } { 180. 45. } { 0.0001 0.0001 } \
{ 1. 0. 0. 1. } { deg deg } FK4 1950.0 { } FITS_PIX { }

ROW: 2 2 { GLON-TAN GLAT-TAN } { 1. 1. } { 180. 45. } { 0.0001 0.0001 } \
{ 0.86 0.5 -0.5 0.86 } { deg deg } { } { } { } FITS_PIX { }

ROW: 2 2 { ELON-TAN ELAT-TAN } { 1. 1. } { 180. 45. } { 0.0001 0.0001 } \
{ 0.86 0.5 -0.5 0.86 } { deg deg } { } {1997.} { } FITS_PIX { }

ROW: Guide 2 { DEIMASKX DEIMASKY } { 1. 1. } { .045 .31 } { 0.001 0.001 } \
{ 1. 0. 0. 1. } { m m } SLITMASK { } { } CCD_PIX { }

ROW: Guide 2 { DEWARFPX DEWARFPY } { 1. 1. } { .010 .008 } \
{ 0.000015 0.000015 } { 1. 0. 0. 1. } { m m } DEWAR_FP { } { } CCD_PIX { }

ROW: 8 2 { DEWARFPX DEWARFPY } { 1. 1. } { 180. 45. } { 0.00001 0.00001 } \
{ 1. 0. 0. 1. } { m m } DEWAR_FP { } { } CCD_PIX { }

ROW: { } { } { DEWARFPX DEWARFPY } { 0. 0. } { 180. 45. } { 8000. 8000. } \
{ 1. 0. 0. 1. } { m m } DEWAR_FP { } { } SLITMASK { }

ROW: { } { } { RA---TAN DEC--TAN } { 0. 0. } { 180. 45. } { 0.25 0.25 } \
{ 1. 0. 0. 1. } { deg deg } FK5 2000.0 { } SLITMASK { }

ROW: { } { } { DEIMASKX DEIMASKY } { 180. 45. } { 0. 0. } { 4. 4. } \
{ 1. 0. 0. 1. } { m m } FK5 2000.0 { } RA--DEC- { }

Take special note of the PROJPn keyword here. In all other cases the dimensionality of the inputs can be determined from the keyword database. This is not so for PROJPn.