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The datasets for EIS Data Compression (DC) factor investigation are chosen as follows:

1. search EIS study database(info) to find out which study has adotped a specific compression scheme such as DPCM, JPEG95, etc. For example, study 29, 30, 31, 32, 91, 92, 142, 255, 258 have ever used JPEG90 compression scheme.

Note:

i. study 29-32 are designed specially for all of compression schemes test, however, only study 29, 30 have generated useful fits files. Also the selection of compression scheme was done in eis_mk_study tool, rather than eis_mk_raster, thus there was no scheme inofrmation in the fits header. In this case one needs to find out manually the scheme for each fits file generated by study 29,30.

ii. Some studies use multiple rasters (eg. study 142), for conevenince of MDP data packet calculation the investigation here only focuses on single-raster study.

iii. check the txt files study_summary.txt(info) for more information about studies and their compression scheme selection.

2. knowing details (eg. ID) of rasters which using a specific compression scheme, one can extract oringinal data volume for these rasters (through EIS planning database), and the corresponding fits files (through EIS science database), then work out the data set for the investigation. Check here datasets_list.txt(info) to find out datesets used in this case.

Note:

i. the datasets chosen here are out from EIS eclipse season

ii. in the 'plot' figures shown below, data points towards right imply themself coming from more recently observations.

Scheme Total QS AR CH 1" 2" 40" 266"
DPCM 2.19(2.38)2.192.192.542.462.192.18
JPEG98 2.462.223.152.85(avg)2.312.28(2.32)
JPEG95 3.643.26 6.126.38(6.54)3.26
JPEG92 3.316.65(avg)2.746.53(avg)2.743.63
JPEG90 3.824.343.734.67(avg) 3.843.78
JPEG85 4.824.514.913.9(avg) 4.51
JPEG75 6.2 18.88(avg) 6.27.52
JPEG65 19.94(avg) 25.97(avg) 7.33(avg)
JPEG50 20.9817.72 17.72