This directory is devoted to illustrating filtering and muting to"clean up" some real data contaminated with ground roll.  Theseactivities are derived from exercises from John Scales's "Theory ofSeismic Imaging", Samizdat Press, available from this ftp site.  Seethat text for full explanations and extensions.  If you are new to SU,start by reading "The SU User's Manual" and/or running the SortTutorial.The data set used in this demo (and in the demo in ../Sufilter) isshotgather #25 from the Oz Yilmaz collection.  These gathers are allavailable by anonymous ftp:ftp ftp.cwp.mines.edudirectory is pub/data/oz.migration.notesfiles are oz25.F and oz25.HATTENTION: If you are on a "big endian" machine (e.g., IBM RS6000,SUN,etc.)  you must run MakeDataBig before running the main demo tomake the data set, data.su.  Similarly, run MakeDataLittle to makethis data set on a "little endian" machine (e.g., DEC, PC's).Demo Files----------XLook: #1. Look at data using par file to supply all parameters #2. Set header fields with sushw and plot using sugain and thesuggested tpow in oz25.H #3,4 Use xmovie option "perc" to clip large data near shot pointXFilter1:The idea is to high pass (low cut) filter the data to get rid of the groundroll.  Use suspecfx to get an idea of the ground roll frequency.XFilter2:Show results of some low pass filters.XMute:Show experiments with sumute to mute the direct arrivalsXGain:Show experiments with sugain to display gain the deep part of the section.-----The PostScript files have the analogous names PSLook, etc. and produce.eps filesFor an example of systematic filter testing, see the Filtertest script in the	CWPROOT/src/su/examples subdirectory.