From spencer Tue Oct 12 10:29:32 1993 From spencer Tue Oct 12 10:29:32 1993 Return-Path: Date: Tue, 12 Oct 93 10:29:16 MST From: spencer (John R. Spencer) To: spencer@sunkng Subject: Galilean Satellite Maps Content-Length: 2890 X-Lines: 62 Status: RO Greetings: I got this message from Alfred McEwen, and I'm passing it along, for anyone apart from the Galileo teams who is interested in digital maps of the Galilean satellites. To read PICS format files on a UNIX system, you need to know that everything is packaged in "blocks" of 512 bytes each, with (sometimes) a termination character at the end of each block so the actual block is 513 bytes in size. Lines are padded to fill an integral number of blocks, so lines are multiples of 512 or 513 bytes long. There is also an initial header which is an integral number of blocks long. I've used this information plus trial and error to read PIC files, but if you know a better way let me know! John. Dear Galileo satellite planners, Global digital maps of the Galilean satellites are available via VMS COPY or UNIX ftp, for use in GLL sequence planning. The files are located in IFLAG2::WORK9:[ANONYMOUS]. (If IFLAG2 not recognized, try ASTROG::IFLAG2::). The files are available in PICS format (.PIC) and in unlabelled fixed-length-record format (.FX). All files are 8-bit (byte). They are: CALLISTO.PIC, CALLISTO.FX Digitized airbrush map, Simple Cylindrical, 1/16 deg/pixel, 2880 lines x 5760 samps, lat -90 to 90, long -180 to 180, positive longitude west. GANYMEDE.PIC, GANYMEDE.FX Digitized airbrush map, Simple Cylindrical, 1/16 deg/pixel, 2880 lines x 5760 samps, lat -90 to 90, long -180 to 180, positive longitude west. EUROPA.PIC, EUROPA.FX Digitized airbrush map, Simple Cylindrical, 1/16 deg/pixel, 2880 lines x 5760 samps, lat -90 to 90, long -180 to 180, positive longitude west. IOBASE.PIC, IOBASE.FX Digital mosaic, Simple Cylindrical, 1/10 deg/pixel, 1800 lines x 3600 samps, lat -90 to 90, long -180 to 180, positive longitude west. To ftp files, type "ftp iflag2.wr.usgs.gov"; at the prompt type "anonymous"; and when it asks for identification, respond with your internet address. You will be in WORK9:[ANONYMOUS] directory. Enter "type image", then send files using ftp send, put, or mput. The Callisto, Ganymede, and Europa maps can be trusted within about 5 degrees lat-lon, and the Io mosaic is accurate to within 1 degree. I realize that 5 degrees far exceeds the size of many targetted high-res mosaics, but we will not have funding until FY95-6 to produce more accurate Callisto, Ganymede, or Europa base maps. The maps are accurate to about 1 degree in most places. The highest resolution coverages of each moon are not portrayed at full resolution, but are shown on published (paper) maps. If you need any such maps, contact Kathy Hoyt (ASTROG::KHOYT by email, or fax to 602-556-7090) and ask her for "one set of all published USGS maps of ______" (Galilean satellite). If you especially desire flat rather than folded maps, please specify (but they may not be available). Cheers, Alfred