IVM File Names This documents some of the file naming conventions that are used to keep IVM files straight. The concern here is mostly with raw datafiles saved on tape or DvD by the IVM instrument computer. There is some discussion of other files that occur during or as a result of the IVM magnetogram reduction. ----------------------------------------------------------------- IVM files have the generic form: Ippp(_CC)YYMMDD.HHmm(ss)(.raw) with ppp file type identifier CC century YY year MM month DD day hh hour mm minute ss second The time elements identify the start time of the first image in the file. ------------------------------------------------------------------ The file type identifiers are: 1) Dark image files IDKR combined Data and Geometry camera images IDK0 Data camera IDK1 Geometry camera The IDKR files are never split. IDKR files began on 20-Apr-1999. The IDK0,1 files were kept separate until 24-Sep-1998. The second (ss) was added to all IDK0,1 files. The IDKR files all have OBLK headers; the IDK0,1 files all have IBLK headers. 2) Flat image files IFSR combined Data and Geometry camera images IFS0 split Data camera images IFS1 split Geometry camera images IFA0 "averaged" Data camera images IFA1 "averaged" Geometry camera images IFSR files began on 20-Apr-1999. Beginning on 10-Oct-2000 they include not only the spectral scan but also images for spurious modulation that are not currently used. The IFS0,1 files were saved for the interval 26-Jan-1998 to 16-Apr-1998. But they were named IFA0,1().raw. The true IFA0,1 files were also saved. And the order of the images in the IFA0,1 files was (pointing,wavelength), whereas the IFS0,1 files from 1999 on are (wavelength,pointing). The IFA0,1 files were generated as the average of the multiple pointings as a common wavelength until 24-Sep-1998 and saved. They are generated as the median of the multiple pointings beginning 20-Apr-1999 from the IFSR files during processing. The IFS and IFA files had IBLK headers until 24-Sep-1998; they have OBLK headers after that date. 3) Cal image files ICAR combined Data and Geometry camera images ICA0 split Data camera images The Geometry images are not recorded, so the split is used for verifying byte order. Only the ICAR files have ever been saved. The ICA files all have OBLK headers. 4) Magnetogram images IMGR combined Data and Geometry camera images IMG0 split Data camera images IMG1 split Geometry camera images Only IMGR have ever been saved. All others are generated in the reduction process. These include: IMG0 split Data camera images IMG1 split Geometry camera images IMGM FITS format magnetogram reduction results IMGA " " " " " from average of several original magnetogram scans The IMGA prefix is not standard. A problem is that all files are named by start time, so some distinction must be made or the latest reduction result will just overwrite the existing one. But if the magnetogram scans are paired before reduction, then the filename is IMGM(...)_pr. So there is not even consistency. Several other issues should be resolved. Quicklook grams are spatially binned and should be labeled uniquely. Files that are averages of reduced grams should be treated differently from those that are reductions of the averages of Stokes spectra as intended here. At some time a standard for files with the vector ambiguity solution and current maps might be useful. --------------------------------------------------------------------------- To summarize the optional elements in parentheses, they depend on time as follows: 1) The century (_CC) is added to all filenames with dates from 28-Oct-1999 onward. 2) The second (ss) was added to the names of dark and flat files for all dates until and including 24-Sep-1998. 3) The (.raw) suffix was added to the names of IFS0,1 (but named IFA0,1) files for the interval 26-Jan-1998 to 24-Sep-1998. ---------------------------------------------------------------------------- Prior to the magnetogram reduction, some procedures produce modified files that are distinguished by suffixes appended to the IMGR filenames. _dpa Data patched - individual bad images replaced by copies of good ones (IVM_DATA_PATCH) _hpa Header patched - incorrect values in a raw header are fixed (IVM_HEAD_PATCH) _pr Paired gram - Used to get multiple spectral scans in a single file for reduction (IVM_GRAM_PAIR) --------------------------------------------------------------------------- The IVM magnetogram reduction procedures, RIVMCAL and RIVM, generate a series of intermediate files. They are distinguished by the various suffixes that are sequentially appended to the split file names. IFA0,1 files: _sw Byte order swapped _inv Inverted flat images ICA0 files: _instr Instrumental matrix derived from the Cal sequence IMG0 files: _df Dark subtracted and flat divided _re Registered for rigid spatial shifts _ic Extinction and spurious modulation corrected _pl Parasitic light corrected _sc Scattered light corrected _ds Differential stretching and seeing corrected _av Averaged over multiple spectral scans _st Instrumental Stokes parameters computed from modulation images _ca Calibrated for instrument matrix polarization response _unb Stokes spectra bias corrected IMG1 files: _wa Warped to get image geometry matched to the Data camera frame of reference --------------------------------------------------------------------------- Barry LaBonte Last modified: Wed Jul 23 09:01:02 HST 2003